POSITIVE Study Findings Shift Conversations on Pregnancy in ER+ Breast Cancer

Jamie Carroll, APRN, CNP, MSN

Data from a short-term follow-up of the POSITIVE (NCT02308085) trial suggests that pausing adjuvant endocrine therapy may be safe for women with hormone receptor–positive breast cancer who wish to pursue pregnancy, according to Jamie Carroll, APRN, CNP, MSN.

Although a long-term follow-up is ongoing, data presented at the 2022 San Antonio Breast Cancer Symposium showed that at a median follow-up of 41 months, among 497 patients, 74% of women had at least 1 pregnancy—with 70% of the pregnancies occurring within 2 years. Birth defects were low at 2%. Additionally, 64% of women had at least 1 live birth. The 3-year breast cancer recurrence rate among patients who halted therapy was 8.9% (95% CI, 6.3%-11.6%).

“Patients who had 18 months to 30 months of adjuvant endocrine therapy, stopped their endocrine therapy, had a 3-month washout, and then were allowed up to 2 years to attempt pregnancy, conceive, deliver, and breastfeed—which included the 3-month washout,” Jamie Carroll, APRN, CNP, MSN, said. “Then, if no pregnancy was achieved by a year, they recommended fertility assessment.”

In an interview with Oncology Nursing News®, Carroll, a nurse practitioner at Mayo Clinic in Rochester, Minnesota, highlighted her interpretation of the trial findings and how this new data will translate to her clinical practice.

Moving forward, Carroll shared that she is interested in learning whether these results will apply to women who wish to pause therapy multiple times to have more than one child.

“One questions that I have is [whether] we will recommend that they take it for another 18 months and [attempt to] achieve another pregnancy,” Carroll noted. “My outstanding question is: is there safety in pausing it once again?”

Oncology Nursing News®: Please describe the POSITIVE study.

Carroll: POSITIVE was a pregnancy outcome and safety [study] of interrupting therapy for women with endocrine responsive breast cancer because patients that have estrogen receptor [ER]–positive breast cancer and are of childbearing age want to know if they can interrupt their endocrine therapy to achieve pregnancy. This was a prospective single-arm study to address that question—is it safe from a breast cancer perspective and will [pregnancy] increase their risk of breast cancer relapse?

The study was looking at only women with ER–positive breast cancer, they were premenopausal [younger than] 42 years of age, and they had to have gotten 18 months of adjuvant endocrine therapy, no more than 30 months of endocrine therapy. [Investigators] did allow prior neoadjuvant or adjuvant chemotherapy plus or minus fertility preservation and [patients] couldn’t have had any clinical evidence of recurrence. The primary end point was breast cancer free interval from time of enrollment.

Approximately 43% were in their upper 30s, 75% had no number of births ahead of breast cancer diagnosis, and then almost all were stage I or II breast cancer, stage III was only 6% of patients. They had varying endocrine therapy with or without ovarian function suppression, [selective estrogen receptor modulator] SERM or aromatase inhibitor. Approximately 62% had prior chemotherapy and approximately half and half had mastectomy vs lumpectomy. The outcomes are showing that pausing the endocrine therapy does not impact short-term disease outcomes.

Is pausing therapy something you point women who are receiving adjuvant therapy to and how might you talk about those conversations?

I have this conversation frequently with patients because I have many premenopausal women who have ER-positive breast cancer. I had this conversation today with a 20-something year old woman who is getting her last cycle of neoadjuvant chemotherapy and is already asking, “Can I look at getting pregnant in the future?”

It's a common discussion that we have and it’s helpful to know that the POSITIVE trial did not see that disrupting endocrine therapy impacted disease outcomes. That’s helpful for patients and providers to know that they’re not seeing an increase in recurrence when endocrine therapy is paused to achieve pregnancy.

Reference

Partridge A, Niman SM, Ruggeri M, et al. Pregnancy outcome and safety of interrupting therapy for women with endocrine responsIVE breast cancer: primary results from the POSITIVE trial (IBCSG 48-14 / BIG 8-13). Presented at 2022 San Antonio Breast Cancer Symposium; December 6-10, 2022; San Antonio, TX.