Dr Graff on the Impact of Endocrine Therapy Interruption on Conception in Breast Cancer Survivors

Stephanie L. Graff, MD, director, breast oncology, Lifespan Cancer Institute, assistant professor of medicine, Warren Alpert Medical School, co-leader, Breast Cancer Translational Research Disease Group, Brown University’s Legorreta Cancer Center, discusses discusses the advantages of interrupting endocrine therapy in premenopausal patients with endocrine-responsive breast cancer who are seeking to conceive, based on findings from the phase 3 POSITIVE trial (NCT02308085).

The POSITIVE trial assessed the feasibility and safety of temporarily suspending endocrine therapy for up to 2 years in breast cancer survivors who are seeking to conceive, Graff begins. The study focused on patients under the age of 42 who were premenopausal at the time of their breast cancer diagnosis and had previously received at least 18 months of endocrine therapy to treat their early-stage, hormone receptor (HR)-positive breast cancer, she details. Additionally, 62% of patients had undergone prior chemotherapy, and the median age in the overall population was 37 years. Although the trial enrolled participants with stage I, II, or stage III breast cancer, only 1% of patients enrolled had stage III disease. Consequently, it is difficult to determine whether results from this study are truly applicable to this population, Graff notes.

Patients on the study received a 3-month washout period from their initial medications, Graff continues, and if pregnancy had not been achieved within 1 year, participants were encouraged to seek fertility consultations, she says.

Results from the POSITIVE trial revealed that patients who underwent an interruption in endocrine therapy treatment achieved breast cancer-free and distant relapse-free intervals that were comparable to historical cohorts from the phase 3 SOFT and TEXT trials (NCT00066690; NCT00066703), Graff reports. Furthermore, 74% of patients were able to have 1 pregnancy. Of the 86% of patients who became pregnant, 64% of all women had at least 1 live birth. Importantly, a relatively low rate of pregnancy complications was reported when considering patients' age and prior history of childbirth, Graff emphasizes.

Overall, findings from the POSITIVE trial suggest that it is safe and appropriate to consider interrupting endocrine therapy interruption after 2 years for breast cancer survivors wishing to pursue another pregnancy, Graff concludes.