ASRM 2011 Updates

In addition to the magical wonders of Disney, Orlando welcomed reproductive endocrinologists from around the world this October to attend the annual meeting of The American Society for Reproductive Medicine (ASRM).  Several members of Pacific Fertility Center were among the participants. 

Preimplantation Genetic Screening (PGS)

PGS was again a hot topic of discussion.  Multiple presentations showcased the recent technological advances in this field.  The ability to perform comprehensive chromosome analysis using microarray technology instead of the first generation method of FISH (fluorescent in situ hydridization), which could only test a selected number of chromosomes at a time, has increased the accuracy and the detection rate of embryonic aneuploidy (abnormal number of chromosomes).  Laboratory advances such as biopsy of the trophectoderm (the outer cell layer of a day 5 embryo) and vitrification (a method of rapid cooling of embryos that minimizes ice crystal formation) have further improved success.  As the result of the above-mentioned technical breakthroughs, we have seen a measurable increase in the pregnancy rate and a decrease in the miscarriage rate from IVF using PGS.  Additionally, two respected groups independently presented data supporting the use of PGS as a successful embryo selection tool to promote elective single embryo transfer (the process of transferring one embryo at a time into the uterus to reduce the risks of multiple gestation).  The pregnancy rates from a single PGS-selected euploid embryo were 58% and 60.7% compared to 42% and 40.7%, respectively, from a morphologically comparable but non-PGS-selected embryo.  Moreover, the miscarriage rates decreased to 6% and 6.3% from 12% and 12.5%, respectively.  The risk of multiple gestation was essentially eliminated (1-2% monozygotic twining).

We were excited to note the parallels between the data presented and our own work at PFC.  Several years ago, we made the commitment towards decreasing our multiple pregnancy rates by adopting a policy of encouraging elective single embryo transfer in qualified patients.  We have found that 24-chromosome aneuploidy screening (via informatics-based single nucleotide polymorphism microarray technology by Gene Security Network) of trophectoderm biopsy has significantly enhanced our ability to select the embryo with the best implantation potential.  Our improved vitrification program has also allowed us to reassure our patients that their unused embryos can be safely stored for future use, thus removing the pressure to transfer more embryos at one setting.  We are very proud of our success so far in achieving our goal as we are currently the number one ranked program in the nation of the fewest number of embryos transferred in donor cycles (1.4 embryos per fresh cycle) while maintaining a high pregnancy rate of 57% (of all programs with more than 20 donor cycles per year, 2009 SART).  For more details on our experience with single embryo transfer and its pregnancy rates, please read “What are my chances of having a baby from a single IVF cycle” by our embryologist, Erin Fischer, and laboratory director, Dr. Joe Conaghan, in this issue of Fertility Flash.

Fertility Preservation

Another interesting topic that deserves attention is fertility preservation using oocyte cryopreservation. Two centers with extensive experience in this area shared their outcome data from both methods of cryopreservation, slow freeze and vitrification.  A center in Atlanta vitrified over 2000 oocytes from donors with an average age of 26 years.  Of the 1772 oocytes rewarmed, 88% survived, 75% fertilized, and 51% resulted in viable cleavage stage (day 3) embryos.  Live birth rate per cryopreserved oocyte was 11%.  The other presentation by a group in New York reported their experience of rewarming 536 cryopreserved oocytes using both slow freeze and vitrification from non-donors with an average age of 32 years.  The overall live birth rate per rewarmed oocyte was 5.5%.  Study is ongoing to compare the efficacies of slow freeze and vitrification.     

PFC’s own data with vitrification of oocytes is comparable to, if not better than, the results presented at our national meeting by various groups across the US.  A 5-10% live birth rate per oocyte in women under the age of 35 years translates to a respectable chance of having a baby in the future from one to two treatment cycles in the present (10-20 oocytes can be expected to be cryopreserved per cycle).   As we further perfect our own techniques of vitrification, we will be increasingly more confident in our ability to offer young women with a viable option for future family planning in addition to embryo freezing and donor gametes.  Future research is needed to achieve the same type of success rates in older women.   

Participating at ASRM is always an educational experience.  We enjoyed sharing our own clinical and research endeavors with our colleagues across the US and all over the world.  Our position as the nation’s leader in many of the most cutting-edge technologies in our field is a validation of our commitment to excellence and to provide our patients with the highest quality care available.

Empowering a woman’s choice using fertility preservation

Protecting and preserving fertility is a new way of empowering reproductive choice. The fertility of youth is no longer a limited resource, constrained by age.  Women can now pursue their reproductive lives at their own pace, rather than according to the obligations of biology.  Reproductive choice means having children when you want them, rather than when you must have them.

Fertility preservation, specifically egg freezing, is changing the way we think about building families.  Through fertility preservation, eggs can be stored and saved for use a later. 

The potential of fertility preservation replaces the tick of the biological clock

The tick-tock of the biological clock influenced reproductive choice in the last decades.  The sacrifice of delaying family while assembling a career, home, and relationship worked in an economic sense.  It did not, however, fit well with the designs of biology. 

Eggs work best at a young age, when there are more of them, and they are more vital. The best pregnancy rates occur in women ages 18-30.  With declining egg numbers and egg quality, pregnancy rates are lower in older age groups, while miscarriage rates and chromosome defects become more common.

Biology wastes eggs

The limit of egg quantity and quality is a consequence of our biology. From mid-gestation through menopause, there is a continuous stream of egg follicles that grow to a certain stage and then are lost.  This pool of eggs is never replenished. Each woman is born with a set number of eggs (over a million), and by puberty perhaps 300,000 remain. Ovulation will happen only 500 times in a woman’s reproductive years. and will result in a child less than 1% of the time.  From start (gestation) to finish (menopause), 1 in a million eggs results in a child.  This constant and dynamic process of decline continues through the reproductive years, uninterrupted by birth control pills, pregnancy or ovulation.

Fertility preservation provides the potential for protection against future infertility

Fertility preservation is a relatively simple process.  The first step is for a woman to see her fertility doctor for an ultrasound and physical exam.  On ultrasound the ovaries are measured and the number of follicles determined.  A treatment calendar with a schedule of injectable fertility drugs is initiated.

Using fertility medications for approximately ten days, multiple eggs begin to mature in the ovaries.  Under sedation, the eggs are retrieved, a process that takes about 10-15 minutes.  The eggs are then cryopreserved and placed in frozen storage.

At a later time, the eggs can be thawed, inseminated with sperm (ICSI is recommended), and the embryo(s) created transferred back into the uterus to develop into a pregnancy.

Technology of Fertility Preservation is improving

We are continuing to optimize the outcomes of oocyte cryopreservation.  In a series of women under age 30 where eggs were cryopreserved, egg survival was 88%.  Over half of the eggs fertilized, and two thirds of transfers resulted in pregnancy.  As of January 2011 Pacific Fertility Center has 8 delivered babies from cryopreserved eggs.

The limits of biology continue to constrain outcomes of those eggs that survive.  Not all eggs have the capacity to produce a viable embryo.  This variable is very age dependent.  In a healthy woman under the age of 30, approximately one third of her eggs(33%) are capable of producing a viable embryo.  In women over the age 40, this ratio changes to one in twenty (5%).

Fertility Preservation:  reproductive choice

The message is this:  Fertility is optimal in your youth.  If you have not started your family, you should consider freezing your eggs for use in the future.

-Philip Chenette, M.D.

Advances in research & development bring a deeper understanding of infertility:

Modern fertility science is changing treatment, enabling better pregnancy rates.  A healthy child for every person suffering from fertility problems remains Pacific Fertility Center’s goal.  Through a better understanding of the egg and embryo we are  closer to delivering on that promise of one healthy baby at a time.

The problem of the aging egg:

The aging egg remains a very basic problem in fertility.  As a woman ages, her eggs do not work as well, resulting in embryos that do not develop or implant.  Mistakes in early cell division, chromosomes, and development become common.  With an aging egg, pregnancy rates are lower and miscarriage risk higher.

Finding that healthy egg can be a problem.  For a twenty year old, roughly 1 in 3 of her eggs will be healthy.  For a woman over forty, less than 1 in 20.  This continues to be a real and ongoing challenge for our patients.

One way to work around this problem is to increase the number of eggs.  Starting with more eggs gives a better chance of finding at least one that is healthy.  Once we have a batch of eggs, the problem emerges of trying to choose the best out of the group.  Which egg is most likely to achieve pregnancy?

Research of early egg and embryo development:

We are excited to share that we are currently working with a privately held medical technology company, along with several other centers in the Bay Area, on a new investigational imaging device in the early stages of development.  We can now observe, using a video microscope, the early stages of embryo development.

Knowledge of the way an embryo develops, the early cell division, when and how, promises to improve selection of embryos.  Over a several year period at Stanford Institute for Stem Cell Biology & Regenerative Medicine, Dr. Renee Pera, in collaboration with Stanford colleagues, Dr. Barry Behr (Associate Professor and IVF Lab Director), Dr. Thomas Baer (Executive Director of the Stanford Photonics Research Center), and post-doctoral fellows Dr. Connie Wong and Dr. Kevin Loewke, conducted ground-breaking research into early human embryo development.  Looking at embryos in their first few days of development, the team identified an elegant set of imaging parameters by day 2 that accurately identified embryos that develop to the blastocyst stage.

Through the use of precision imaging technology coupled with novel measurements, embryologists may be able to choose the best embryos more accurately and consistently.  Published last year in Nature Biotechnology, Time magazine named the discovery one of the 10 medical breakthroughs of 2010.

Dr. Renee Reijo Pera, Ph.D.

Dr. Renee Reijo Pera, a leader of the team that published this study, understands these problems, working with them in a research lab for the last twenty years.  She is now bringing that knowledge to clinical medicine.

Dr. Pera received her PhD from Cornell University, and later worked in David Page’s lab at the Whitehead Institute.  While working with Dr. Page, she discovered a gene on the Y chromosome that was involved in male fertility called the DAZ (Deleted in AZospermia) gene.  As it turns out, the gene accounts for a significant proportion of male infertility and tests for this gene are now routine for men with low sperm counts.

Now, as Director of Stanford University’s Center for Human Embryonic Stem Cell Research and Education, Dr. Pera’s focus is on understanding issues related to human reproductive failure.  The questions she and her team are addressing encompass issues such as Egg formation and development, as well as what triggers cell division and formation of a healthy embryo

Fertility care will change based on Dr. Pera’s research on early development of eggs and embryos.  This work has vast implications for the future of treatment and prevention of infertility.  In her exploration, she is finding new ways of thinking about old fertility problems.  Dr. Pera’s work will strongly influence medicine and clinical realm for years to come.

At Pacific Fertility Center we are committed to bringing advanced science to the clinic.  We are finding major changes in our understanding of early egg and embryo development and anticipate continuing to lead the way in bringing these advances to help our patients have one healthy baby at a time.

-Philip Chenette, M.D.

Since March of 2007, PFC has been vitrifying embryos.  We have now completed over 600 warming cycles, utilizing those embryos.  Vitrification is proving to be a very reliable technology to preserve any unused embryos that remain after a fresh transfer. We continue to adjust our technique and thus increase the successful results of vitrification.  Last year, we introduced a modification to the procedure that allows us to remove the fluid from the cavity in a blastocyst before we begin vitrifying.  As with any freezing procedure, cell water must be substantially removed and replaced with cryoprotectants to avoid ice formation in the cells.  Five and 6 day old embryos, or blastocysts, can have a large fluid filled cavity that slows dehydration and passage of cryoprotectant into the cells.  Since vitrification is an ultra-rapid freezing procedure, any delays caused by the fluid in the cavity may affect the ability of the embryo to survive the procedure.  By making a small breach between two of the outer cells in the embryo, we are now allowing the cavity to collapse prior to beginning the vitrification procedure.  This artificial collapsing has further enhanced results.  We are seeing implantation rates with warmed embryos that are very similar to those achieved with fresh embryos.

Overall, from 636 warming cycles, we have achieved 284 clinical pregnancies (45%) in all age groups combined.  In younger patients (maternal age under 35), there were 103 successful clinical pregnancies from 190 transfers (54%) with an average of just 1.7 embryos transferred.  This pregnancy rate drops to 42% (41/97) in 36-37-year-old patients with an average transfer of 1.8 embryos.  In the 38-40 age group there were 31 pregnancies achieved successful from 79 transfers (39%). For patients over age 40, 8 of the 23 transfers were successful (35%).  In the donated oocytes group, 101 pregnancies resulted from 247 transfers (41% with an average of 1.7 embryos transferred).  For patients that had their embryos artificially collapsed, the results were better.  However, since this is a new technique, the number of cycles is small.

Overall, we are very pleased with the outcomes achieved with vitrified embryos.  We are optimistic that results will continue to improve.  The table above shows results for all cycles completed since the beginning of the vitrification program.  As our experience grows, so do our success rates.  Reviewing cycles of patients that had embryos warmed and transferred from just this year (Jan-Oct 2010), we see that the outcomes are exceptionally good, particularly  for patients whose embryos  were collapsed prior to vitrification.

At PFC we are continuing to vitrify all embryos by day 5 or 6 after oocyte retrieval if they are good or reasonable quality blastocysts.  We now routinely collapse any blastocyst with an expanding cavity.  These procedures have worked well.  Consequently, it has become necessary to reduce the number of embryos being transferred to avoid generating too many multiple pregnancies.  Our goal is to achieve a healthy singleton pregnancy in all patients; vitrification has allowed us to reduce the incidence of multiples by transferring just a single embryo most of the time.  For our 2009 fresh cycles, in patients under 35, 40% of the time we transferred just one embryo, and in patients using donor oocytes 60% of the transfers were a single embryo.  Vitrification has proved to be so successful that many patients have elected for a fresh single embryo transfer; virtually eliminating their risk of twins and knowing that their frozen embryos will be available should they be needed.

Every year, several Pacific Fertility Center professionals participate in ASRM’s national meeting. They evaluate the research and share their findings with PFC and Fertility Flash.

Among those attending the conference from PFC were Dr. Philip Chenette and Dr. Isabelle Ryan and Peggy Orlin, MFT. Their reviews cover the following topics: Update #1: Ovarian Stimulation Techniques, Update #2: PGD and Aneuploidy Screening Techniques, Update #3: Egg Freezing, Update #4: Acupuncture, and Update #5: Men and ART.

ASRM Update #3: Egg Freezing

Oocyte cryopreservation is the storage of the female gamete, the egg, prior to fertilization. Preservation of fertility for single women that must undergo cancer therapy or surgery, or that must delay or choose to delay childbearing, and donated oocyte banking are all applications of oocyte cryopreservation. The need for this technology is clear, but reports of success with oocyte cryopreservation have been limited.

Highly successful oocyte cryopreservation is now attainable. New studies are showing pregnancy rates with oocyte cryopreservation that are equal to traditional IVF techniques.

The key to this technology is oocyte vitrification – an ultrarapid cryopreservation technique. Researchers from Atlanta described their experience with vitrification. Out of 11 patients with transfers, nine conceived, with an implantation rate of 65%.

Pregnancies after oocyte cryopreservation have developed normally. An Italian study of 105 children born after oocyte cryopreservation showed no problems. A Chicago study of the genetics of oocytes, embryos, and children born after oocyte cryopreservation was reassuring. No increase rates of aneuploidy or malformations were reported, and normal development was found in post-natal follow-up.

These results are similar to those we have previously reported from our own research at Pacific Fertility Center (see December 2007 Fertility Flash). Oocytes are now cryopreserved with high success rates. Oocyte cryopreservation technology has matured, and we look forward to providing these techniques for our patients.

Philip Chenette, MD

Question: I am 35 years old and single, but am still hoping to find my life partner. I am getting a little concerned as my gynecologist has asked me about my plans for having children. She mentioned that I might want to consider freezing my eggs for future pregnancies. Is this something I should do?

Answer: Vitrification is a very new process for preserving unfertilized eggs. As noted in this month’s lead article, PFC has successfully been vitrifying oocytes from proven egg donors. Our first birth from this process occurred in October. Three additional pregnancies from this trial are ongoing. PFC undertook this vitrification trial in order to develop expertise with the technology of oocyte vitrification. For this reason, our study population was confined to donor eggs from healthy donors in their mid-twenties who had successfully completed conventional egg donation.

Why do we want to freeze eggs? For the many single young women diagnosed with cancer and facing fertility-threatening chemotherapy, egg vitrification will provide a fertility preservation option. This group of women has a compelling reason to consider undertaking the procedures and costs involved with in vitro fertilization. The potential threat to their ability to have their own biological children in the future may justify the unknowns that are involved with preserving their eggs in this manner. These unknowns include whether their eggs will survive the vitrification process and whether egg vitrification will ultimately prove to be as safe as conventional in vitro fertilization and embryo cryopreservation. The answers to these questions may not be answered until the patient’s eggs are warmed, fertilized and implanted, which may be years later.

We recognize that a much broader spectrum of the population will look upon oocyte vitrification as a way for women to preserve their fertility. Single women, such as you, who have not yet met their life partner, may be particularly interested in this option. In addition, it may also become an option for women in their 30’s who wish or need to delay their childbearing.

Many questions remain unanswered. Will eggs from women in their 30’s do as well as eggs from proven egg donors in their 20’s? Logic suggests older eggs will not do as well, but will the differences be significant? How many eggs would a woman need to preserve in order to have a reasonable chance for one or two children in the future? How many IVF cycles will that take? Is it safe to rely on these preserved eggs? Would having preserved eggs change a woman’s approach to reproductive planning in her life?

These are not trivial issues. They are important, life-changing concerns. For these reasons, we are not encouraging single women to prematurely jump on the egg vitrification bandwagon. Stay tuned. This area is changing rapidly.

Dr. Carolyn Givens

In late October of this year, our first patient who underwent embryo transfer with embryos created from vitrified and warmed donor oocytes has successfully delivered. The baby was born at term and appears to be perfectly healthy.

Three other pregnancies are ongoing and are expected to deliver in 2008. We congratulate our new parents and the parents-to-be who have participated in this ground breaking program.

PFC has ended enrollment of patients into this program, but expects to continue research efforts with respect to oocyte vitrification.

While it has been possible to preserve sperm for many years (the famed Dutch microscopist Anton von Leeuwenhoek allegedly cooled and then recovered sperm using snow and ice in the 17th century), reliable methods for oocyte preservation have been elusive.

We previously discussed some of the problems with oocyte freezing (see Fertility Flash, January 2005, Volume 3, Issue 1), and now report our success in overcoming some of the obstacles.

Traditionally, preservation of sperm and embryos has been achieved with the use of a technique called slow freezing. This process incubates the sperm or embryos in low concentrations of cryoprotectants (antifreeze) to draw water out of the cells. After this incubation, they are cooled very slowly to sub zero temperatures. Typically this slow freezing technology just works for cells that exist individually (such as sperm), or together in small numbers (embryos), as the water must be extracted from every cell. Tissues, which are made up of many hundreds of thousands of cells, cannot be dehydrated successfully and therefore cannot be frozen intact. Cells in the tissue can burst when the water remaining in the cells expands as it turns to ice. For example, it is not possible to freeze a whole ovary, but some success has been achieved with ovaries that were cut into tiny pieces.

Frustrated by the lack of progress with slow freezing, scientists have more recently moved towards a technology called vitrification for oocyte preservation. Vitrification, which was described in detail in September’s Fertility Flash (Volume 5, Issue 8 ) works by using higher concentrations of cryoprotectants and much faster cooling rates. Cells are typically cooled in tiny straws (see article heading). This process allows us to achieve cooling rates of several thousand degrees per minute.

When vitrification straws and cryoprotectants were first approved by the FDA for human embryos, PFC began the process of adapting the technology to oocytes. Our embryologists attended training courses and became proficient with the technology by practicing on mouse and hamster oocytes and embryos. Even though we have been handling oocytes and embryos for many years, this technology provided many new challenges, mainly due to the tiny size of the straws and the speed at which the cells had to be cooled. Once we became proficient with the procedure, we began to freeze high quality oocytes from donors who had proven fertility. In this way, we knew that if the procedure did not work, it would be the vitrification technology and not the oocytes that were to blame. In addition, we satisfied ourselves that the technology was safe by looking at the exhaustive work by Dr. Gary Smith at the University of Michigan, which showed that vitrified/warmed oocytes were both physically and genetically normal and that the resulting pregnancies and babies were healthy.

We recruited five oocyte donors and vitrified all of their oocytes immediately after their oocyte retrieval procedures. We then offered the oocytes to individuals who were on our waiting list to accept donated embryos. Typically, these individuals were unable to get pregnant with their own oocytes or financially unable to proceed to an egg donor cycle. The availability of the vitrified oocytes was a great alternative to accepting donated embryos as it allowed couples to choose their own sperm source. Furthermore, the immediate availability of vitrified oocytes was an attractive alternative to what may be a very long wait for donated embryos.

Pacific Fertility Center had immediate success with the first recipient. We had vitrified 16 oocytes from the first donor, and for the first recipient we warmed only 7 of these. Four hours later we injected a single sperm into each of the 6 oocytes that appeared alive and healthy (1 oocyte had not come through the process successfully). The next morning, 3 of the oocytes fertilized normally. After 2 more days, we had 3 nice embryos for transfer. The positive pregnancy test 11 days later, and a singleton pregnancy confirmed by ultrasound at 7 weeks were great rewards for our efforts and thrilling news for the recipient. Our second recipient used a different donor and although her pregnancy started out well, she miscarried in the first trimester. Our disappointment over this loss was compounded when we discovered the oocytes from 2 of the donors did not survive well when warmed. In these particular donors, we recovered high numbers of oocytes (each had close to 40) and for unknown reasons their oocytes were overly sensitive to vitrification. The next three donor cycles proceeded well and resulted in pregnancies. These 3 pregnancies are all ongoing at the time of writing. We will update readers with their outcomes at a future date.

Although we were warming relatively small numbers of oocytes (typically 6 or 7), we began to have more embryos than could be safely transferred to recipients. Our first pregnancy had been achieved after transferring 3 embryos. It is more typical, however, to transfer only 1 or 2 embryos when donor oocytes are used. Even when using only 2 embryos, multiple pregnancy rates were unacceptably high. Understandably, few patients are willing to risk a decreased chance of conceiving by transferring only a single embryo. In order to avoid high multiple pregnancy rates in a typical IVF cycle, embryos are usually cultured for 5 days to determine which embryos in a cohort have the best chance of establishing a pregnancy. However, if a patient has only a few embryos, the benefits of extended culture are less, and the transfer is typically done after only 3 days growth. With our recipients of the vitrified oocytes, we began by doing 3-day transfers. Once high success rates were evident, we elected to implement day-5 transfers, in an effort to decrease high order multiples. The last 2 pregnancies both resulted from day-5 transfers of 2 embryos each, and they are both twin gestations.

In summary, we have had 7 out of 10 embryos implant after transfer (excluding the 2 failed donors with the high oocyte numbers). This implantation rate (70%) is comparable to the implantation rates that our patients have when using fresh embryos from donor oocytes.

We are moving forward cautiously with our oocyte vitrification program and hope to use the remaining oocytes soon. While these results are encouraging and have brought great joy to a small number of our patients, there are more issues to resolve before we declare complete success. The 70% success rate was obtained with the use of the highest quality oocytes from young donors who were known to be fertile and healthy. We have already seen that some oocytes are less tolerant of the procedure, as evidenced by the results from the 2 donors with high oocyte numbers. We also fully anticipate that the results for older women using their own oocytes will be worse, as they are for these same patients using a fresh IVF cycle. In fact, at this time, we do not have any idea if the oocytes from women in their 30’s will be able to tolerate vitrification.

Going forward, we will offer oocyte vitrification unconditionally to women with cancer who are likely to be left sterile by their treatment. For these women, and for others who elect to vitrify oocytes for social reasons, we will exercise great caution in our estimates of future pregnancy potential with the warmed oocytes. Until we have more data with oocytes from a variety of women, we will have no way of telling if there is any hope from anything other than donor oocytes. That data will accumulate more slowly because women who elect to preserve oocytes are not likely to be using them for some time. For now, until there is more data, we continue to believe that embryo freezing has the greatest potential for those wishing to preserve future fertility. However, for those who are single and in their late 30’s, we will be reluctant to recommend oocyte vitrification as a reliable fertility preservation method. Hopefully, they will find Mr. Right before we have objective data.

Joe Conaghan, PhD, HCLD

Introduction

Sara (a hypothetical patient) found a breast lump. 36 years of age, she was a single active professional, otherwise healthy, careful about her diet, and carefully evaluating her options after a diagnosis of breast cancer. Along with the discussion on surgery, chemotherapy, and radiation therapy came the question “Were you planning to have children?”

A diagnosis of cancer presents many decisions that must be made quickly. Confirming the diagnosis and planning therapy will be the primary concerns, but the implications of therapy on long-term quality of life must be assessed. One of the primary issues facing women with a diagnosis of cancer is future fertility.

Candidates

Cancer treatment can interfere with future fertility. Toxicity varies by treatment. Cyclophosphamide, an alkylating agent used in many chemotherapy regimens, is highly toxic to sperm and eggs; methotrexate and 5-flouro-uracil (5FU) are not. Medications used for longer time intervals create a higher risk of fertility problems than shorter time intervals; effects on women in older age groups are more severe than younger. Radiation therapy, in high doses, can have effects on eggs and sperm. Surgery and anesthesia are not known to have direct effects.

It is difficult to give specific fertility risks for chemotherapeutic regimens, since studies are not yet definitive. Among the more toxic treatments are stem cell transplantation for leukemia in which total body irradiation and cyclophosphamide are used, beam radiation to a field that includes the ovaries, and extended chemotherapy of up to 6 cycles using cyclophosphamide in combination with other agents. After conventional chemotherapy for breast cancer for women under 40, the chance of infertility is roughly 50%, in older women the risk is over 80%.

Treatment options

What are the options for fertility in patients diagnosed with cancer? The best choices are available to those that have not yet initiated treatment and involve cryopreservation. During treatment, the risk of problems rises, and after treatment, there may not be adequate recovery of fertility to achieve pregnancy.

Cryopreservation allows cells to be stored with great stability for long periods of time. The record time from sperm cryopreservation to pregnancy is 28 years; there probably is no real limit to the time that cells can be stored. To store cells requires technology that reduces the formation of ice crystals, which disrupt cells, and prevents the rapid rise in salt concentration that occurs as water freezes. Cryopreservatives and management of temperature changes (slow freeze or vitrification) are used to reduce the risk of these problems.

Male

The option for fertility preservation in men is straightforward, cryopreservation of sperm. Sperm is obtained by masturbation and frozen in multiple vials in liquid nitrogen. 2-3 sperm samples can be obtained per week, with 2-4 vials stored per ejaculate; two weeks worth of donations could yield 8-24 vials of sperm. Costs vary widely, but would range from $1500-$3000 for processing and 3 years of storage.

Testicular sperm extraction is an option for individuals with azoospermia. Testicular tissue cryopreservation remains a theory that has not yet produced a human pregnancy. It has been proposed as an option for preservation of fertility in children, but has yet to be proven in clinical practice.

Female

Women have the option of cryopreservation of oocytes or embryos. For women without a partner, oocyte cryopreservation holds promise as a means to preserve fertility potential without committing to a specific sperm source or partner. For women with a partner or sperm donor, embryo cryopreservation is a proven technology.

To create cryopreserved oocytes, Follicle Stimulating Hormone (FSH) is administered over a ten day time period to stimulate ovarian follicles. The oocytes are retrieved under sedation with a needle guided by ultrasound and then stored in liquid nitrogen.

Newer techniques of oocyte vitrification secure good pregnancy rates for those with good oocyte quality. Traditional oocyte cryopreservation is performed using a slow freeze technique, but more rapid vitrification procedures optimize results. The trick with cryopreservation is to lower the temperature while avoiding ice crystals that disrupt cell membranes and proteins. Vitrification, an ultrarapid freezing process utilizing a minimal fluid volume, reduces the risk of these problems and optimizes cell quality.

For those women with a partner, or that are willing to commit to a specific sperm donor, embryo cryopreservation is an excellent option. After stimulation and retrieval, oocytes are inseminated and cultured in an incubator for 1-5 days, followed by cryopreservation. The embryos can be thawed and transferred at a later date, after clearance from the oncologist. Embryo cryopreservation is the best established of the fertility preservation techniques, with years of experience in its applications. Good pregnancy rates can be anticipated.

Ovarian tissue cryopreservation, the cryopreservation of whole pieces of the ovary, as opposed to cells, remains experimental. Complex tissues are more difficult to cryopreserve than cells, though rare success has been reported.

Cancer recurrence

Is there risk to the use of fertility drugs in patients with cancer? It does not appear in studies to date that breast or ovarian cancer risk is affected by use of fertility drugs. Studies indicating an increased risk are balanced by other studies indicating a reduction in risk. Studies to date have been limited, and treatment decisions still must be individualized.

Does pregnancy increase the risk of cancer recurrence? In theory, certain types of cancer could be aggravated by the hormones of pregnancy, but studies have not confirmed an overall risk. Certain types of cancer are less common in women that have delivered a pregnancy. Treatment decisions must be individualized, as future studies gather more information.

Pregnancy

Certain cancer treatments create organ toxicity that must be evaluated in considering patients for pregnancy. Heart output is limited in patients that have received doxorubicin. Uterine irradiation is associated with miscarriage and pre-term labor.

Children

Children born after fertility preservation procedures do not carry any increased risk for birth defects. There are hereditary syndromes that can be associated with cancer that could be transmitted to children, but there does not appear to be any other increased risk for cancer or genetic disease in children of cancer survivors.

Patients contemplating conception must consider life span expectations as part of their decision on whether to conceive. Such considerations are not, however, a reason to withhold treatment, and are ultimately the individual and family should decide.

Philip E. Chenette, MD

Resources:

www.fertilehope.org Fertile Hope

www.livestrong.org Lance Armstrong Foundation

www.cryobank.com California Cryobank

www.PacificFertilityCenter.com Pacific Fertility Center

Many patients receiving medical care for infertility will use cryopreserved (frozen) sperm, oocytes and/or embryos at some time during their treatment. Here in the PFC laboratory, we routinely cryopreserve sperm and embryos. We also receive specimens from sperm banks nearly every day. All of these specimens are stored on-site in our secure tanks with continuous monitoring. All specimens are stored in liquid nitrogen at -196ºC. Movement in or out of the tanks only happens when specimens are transferred post freezing or retrieved for thawing or shipping. We store sperm and embryos for our patients for an annual fee as long as we are able to maintain yearly contact with them and the annual storage agreement is renewed.

The shipping of tissues that are frozen and stored at such a low temperature is not easily accomplished. The liquid nitrogen in which they are stored is not toxic in any way, but it is extremely dangerous and can cause serious injury and even death if not handled properly.

In attempting to transport tissues that are normally stored in liquid nitrogen, we have to use a device that will keep the tissues in their same deep frozen state. This is accomplished using a “Dewar” which resembles a large thermos. A Dewar is a vacuum insulated container, mostly filled with an absorbent lining that soaks up liquid nitrogen. The Dewar is “charged” prior to use by filling it with liquid nitrogen over successive days until it will absorb no more. Once saturated, the excess liquid is poured off and the Dewar is then ready for use. Specimens are loaded into the hollow core and they are maintained in their frozen state by the cold nitrogen vapor evaporating from the surrounding absorbent layer. The Dewar holds an appropriate temperature for as long as nitrogen remains inside. Loss of nitrogen by evaporation happens continuously. Typically a fully charged Dewar maintains temperature for between 7 and 30 days depending on its size, how often it is opened and how well it was charged before use. With any Dewar however, loss of refrigeration occurs after a certain period of time, unless more nitrogen is added. In addition, dropping the Dewar or otherwise damaging it in any way can crack the container and this will result in instant failure of the vacuum seal with subsequent loss of nitrogen and thawing of the contents.

When we receive a shipment of sperm from a bank, there is always a risk that the Dewar was damaged or that there was a shipping delay that was longer than the life of the liquid nitrogen in the tank. If the specimens have thawed, typically the sperm bank will replace them at no cost. However, their liability is limited to replacing the sperm, and if you just lost the last 3 vials of your favorite donor, you’ll have to choose a new donor.

Shipping of embryos is a much more risky proposition. Embryos can’t be replaced in the same way that a sperm sample can be replaced, if they can be replaced at all. The major shipping companies such as FEDEX, UPS and DHL will not knowingly accept embryos for transport and therefore would not have any liability for loss. At PFC we discourage shipment of embryos due to the risks involved. We will not ship embryos from our laboratory on your behalf, however you can come and collect your embryos in person and ship them yourself. We will ask you to sign papers releasing us of any liability once the embryos leave our office. We cannot accept any liability for embryos that are being shipped in from elsewhere; it is a practice that we discourage.

If you absolutely must ship embryos, we suggest that you contact a company that has the expertise and the experience to make this type of shipment as safe as possible. Locally, we recommend “Swift Stork Courier” (www.swiftstork.com) who will arrange collection and delivery of the embryos and ensure appropriate and safe handling during transport. For long distance shipments, we put patients in contact with “Kynisi Courier Systems” (email: kosta@kynisi.com), a company based in the UK that specializes in shipping embryos. If you want to send your embryos from

San Francisco to Detroit, or Dublin or Dubai, Kynisi is the only company we know that can get embryos on airplanes without being x-rayed in security. They also get advance clearance to make sure that embryos don’t get delayed in customs as they cross international borders. Kynisi can also arrange for an embryologist to travel with your embryos, and they can organize for the embryos to travel in the passenger cabin of the aircraft, as opposed to being thrown in the luggage compartment with the other cargo. This is important, as a Dewar left lying on its side will lose nitrogen more rapidly than when upright. Kynisi’s services aren’t inexpensive, but considering that the embryos are priceless, there really isn’t a good alternative.

For those patients considering moving their frozen tissues to a facility that offers long-term storage at reasonable costs, we recommend “ReproTech” (www.reprot.com) in Reno, NV. ReproTech is experienced and knowledgeable, and gives great customer service. They too can arrange safe movement of your tissue from us to them, and back again with minimal inconvenience. They often take the extra precaution with embryos by splitting them into 2 groups that are then shipped separately. ReproTech shares the PFC philosophy of thinking of embryos as irreplaceable, and they take every known precaution to ensure a safe and efficient shipment. However, despite the good work of ReproTech, Kynisis and others, I recommend that you do not ship your embryos. The risks are too great.

Joe Conaghan, PhD