SAN ANTONIO — who pause endocrine therapy to conceive, according to new data from the POSITIVE trial.
“We believe these data are of vital importance for the oncofertility counseling of young breast cancer patients,” Hatem A. Azim Jr., MD, PhD, adjunct professor, School of Medicine and Breast Cancer Center, Monterrey Institute of Technology, Mexico, said in a presentation at the San Antonio Breast Cancer Symposium.
As reported previously by this news organization, the primary results of the POSITIVE trial showed that interrupting endocrine therapy to allow pregnancy does not increase the risk of recurrence at 41 months follow-up.
Yet, there is concern that use of fertility preservation or assisted reproductive technology methods — especially those that entail the use of hormones — could have harmful effects on patients with HR-positive breast cancers, Dr. Azim explained.
To investigate, Dr. Azim and colleagues did a secondary analysis of outcomes from the POSITIVE trial, focusing on resumption of menstruation and use of fertility preservation and assisted reproductive technologies.
Among 516 women evaluated for the menstruation analysis, two thirds were aged 35 and older and a little more than half (53%) reported amenorrhea at enrollment, “which is not surprising,” Dr. Azim said.
“What is encouraging,” he said, is that 85% of women recovered menses within 6 months and 94% within 12 months of pausing endocrine therapy.
Among 497 evaluable participants who paused endocrine therapy to attempt pregnancy, 368 (74%) became pregnant.
Looking at time to pregnancy, there was a clear association between younger age at enrollment and shorter time to pregnancy. The cumulative incidence of pregnancy at 12 months was 64% in women younger than age 35 years, 54% in those aged 35-39, and 38% in those age 40-42. In a multivariable model, age < 35 was the only factor independently associated with a shorter time to pregnancy.
No Harmful Impact on Breast Cancer Outcomes
Turning to fertility preservation and use of assisted reproductive technologies, roughly half of the women (51%) underwent some form of fertility preservation at breast cancer diagnosis and before trial enrollment, most commonly ovarian stimulation for embryo or oocyte cryopreservation.
After enrollment, 43% of women underwent some form of assisted reproductive technology to attempt pregnancy, most commonly ovarian stimulation for in vitro fertilization (IVF) and cryopreserved embryo transfer.
In the multivariable model, cryopreserved embryo transfer was the only assisted reproductive technology significantly associated with a greater chance of becoming pregnant, more than doubling patients’ odds (odds ratio, 2.4).
“This means that at breast cancer diagnosis, we should consider cryopreservation of embryos for future use if desired,” Dr. Azim said.
Again, age mattered. Women younger than 35 undergoing assisted reproductive technologies had a 50% higher chance of becoming pregnant compared with peers aged 35-39, and an 84% higher chance than women aged 40-42.
Importantly, there was no apparent short-term detrimental impact of fertility preservation and/or assisted reproductive technologies on breast cancer outcomes, Dr. Azim reported. At 3 years, the breast cancer-free interval was almost identical between women who underwent ovarian stimulation for cryopreservation and those who did not (9.7% vs 8.7%).
“POSITIVE showed positive results that emphasize the importance of active oncofertility counseling with the patient starting at diagnosis,” said Hee Jeong Kim, MD, PhD, professor, Division of Breast Surgery, Asan Medical Center, Seoul, Republic of Korea, and discussant for the study.
“These data are reassuring for our young patients with a diagnosis of breast cancer and shows that assisted reproductive technology is an option and is probably safe to do with the caveat that it needs longer follow-up,” added SABCS codirector Carlos Arteaga, MD, director, Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, Dallas.
Dr. Azim has no relevant disclosures. Dr. Arteaga is a scientific adviser to Novartis, Lilly, Merck, AstraZeneca, Daiichi Sankyo, OrigiMed, Immunomedics, PUMA Biotechnology, TAIHO Oncology, Sanofi, and the Susan G. Komen Foundation. He has received grant support from Pfizer, Lilly, and Takeda. Dr. Kim reports no relevant financial relationships.
A version of this article appeared on Medscape.com.