Q3. How successful are the approved fertility preservation options in obtaining oocytes for future utilization by ART?
A: We have decades of experience with embryo cryopreservation and proven success rates that patients can check on the SART.org website for individual clinics. For oocyte cryopreservation, models are used to provide calculation estimates because the technique is less established.12 Although success rates are approaching those with fresh oocytes, they are still not equal.13 OTC followed by orthotopic tissue transplantation has the least outcomes data (approximately 200 reported livebirths to date with a 25% live birth rate per recipient worldwide10 since the first success was reported in 2000.2,14
With our robotic surgical approach to orthotopic and heterotopic ovarian tissue transplantation and the utility of neovascularizing agents, we have found that ovarian graft longevity is extended. Oocytes/embryos can be obtained and has resulted in one to two livebirths in all our recipients to date.10 Unfortunately, if any of the critical steps are not up to standards (freezing, thawing, or transplantation), success rates can dramatically decline. Therefore, providers and patients should seek centers with experience in all three stages of this procedure to maximize outcomes.
Q4. Are there concerns of increasing recurrence/mortality with fertility preservation given hormonal exposure?
A: Yes, this concern exists, at least in theory for estrogen-sensitive cancers, most commonly breast cancer. We developed ovarian stimulation protocols supplemented with anti-estrogen treatments (tamoxifen, an estrogen-receptor antagonist, and letrozole, an aromatase inhibitor) that appear equally effective and reduce estrogen exposure in any susceptible cancer.15,16 Even in estrogen receptor–negative tumors, high estrogen exposure may activate non–estrogen receptor–dependent pathways. In addition, even those tumors that are practically deemed estrogen receptor negative may still contain a small percentage of estrogen receptors, which may become active at high estrogen levels.
Therefore, when we approach women with estrogen-sensitive cancers, e.g., breast and endometrial, we do not alter our approach based on receptor status. One exception occurs in women with BRCA mutations, especially the BRCA1, as they have 25% lower serum anti-müllerian hormone (AMH) levels,8,17 yield fewer oocytes in response to ovarian stimulation,18,19 and have lower fertilization rates and embryo numbers20 compared with those without the mutations.
Q5. Are all reproductive centers capable of offering fertility preservation? If not, how does a patient find a center?
A: All IVF clinics offer embryo and, presumably, oocyte cryopreservation. Pregnancy outcomes vary based on the center’s experience. Globally, major differences exist in the availability and competency of OTC along with the subsequent transplantation approach. A limited number of centers have competency in all aspects of OTC, i.e., cryopreservation, thawing, and transplantation. In general, fertility preservation patients have a multitude of medical issues that necessitate management expertise and the bandwidth to coordinate with cancer health professionals. The reproductive centers offering fertility preservation should be prepared to respond immediately and accommodate patients about to undergo gonadotoxic treatment.
Q6. How should a patient be counseled before proceeding with fertility preservation?
A: The candidate should be counseled on the likelihood of damage from gonadotoxic therapy and all fertility preservation options, on the basis of the urgency of treatment and the woman’s long-term goals. For example, the desire for a large family may compel a patient to undergo multiple cycles of ovarian stimulation or a combination of oocyte/embryo cryopreservation with OTC. In patients who are undergoing embryo cryopreservation, I recommend preimplantation genetic testing for aneuploidies, although there are limitations to its application. Other novel pieces of information we are using in counseling are baseline AMH levels and BRCA mutation status for women with breast cancer. In an 8-year-long NIH-funded prospective longitudinal study we found that women with both baseline AMH < 2 ng/mL and BRCA mutations are at significantly higher risk of losing their ovarian reserve and developing amenorrhea.21 Because the oocytes of women with BRCA mutations are deficient in DNA repair as we have previously shown,19 they are more liable to death upon exposure to DNA-damaging cancer drugs such as cyclophosphamide and doxorubicin.22