Wednesday, May 31, 2023 CCTG MAC18 study ( Alliance A221405/ BIG 8-13 POSITIVE ) an valuation of the temporary interruption of adjuvant endocrine therapy for pregnancy in young breast cancer survivors in POSITIVE, a single-arm trial results have been published in the New England Journal of Medicine. Partridge AH, Niman SM, Ruggeri M, Peccatori FA, Azim HA, Colleoni M, Saura C, Shimizu C, Sætersdal AB, Kroep JR, Mailliez A, Warner E, Borges VF, Amant F, Gombos A, Kataoka A, Rousset-Jablonski C, Borstnar S, Takei J, Lee JE, Walshe JM, Ruíz-Borrego M, Moore HCF, Saunders C, Bjelic-Radisic V, Susnjar S, Cardoso F, Smith KL, Ferreiro T, Ribi K, Ruddy K, Kammler R, El-Abed S, Viale G, Piccart M, Korde LA, Goldhirsch A, Gelber RD, Pagani O. Interrupting Endocrine Therapy to Attempt Pregnancy after Breast Cancer. N Engl J Med 388: 1645-56, 2023. https://www.nejm.org/doi/full/10.1056/NEJMoa2212856?query=featured_home Among select women with previous hormone receptor–positive early breast cancer, temporary interruption of endocrine therapy to attempt pregnancy did not confer a greater short-term risk of breast cancer events, including distant recurrence, than that in the external control cohort. Further follow-up is critical to inform longer-term safety. (Funded by ETOP IBCSG Partners Foundation and others; POSITIVE ClinicalTrials.gov number, NCT02308085. opens in new tab.) Eligible women <42 years with stage I-III disease, received 18-30 months of prior adjuvant endocrine therapy and desired pregnancy. The primary endpoint was breast-cancer-free interval (BCFI, time from enrollment to first breast cancer event). The primary analysis planned 1600 patient-years follow-up, with >46 BCFI events as safety threshold. To supplement the primary analysis, BCFI and distant-recurrence outcomes were compared to an external control from the SOFT/TEXT trials using Bootstrapped Matching Method. Of 518 women enrolled, the median age was 37 years. Median time from diagnosis to enrollment was 29 months, 93.4% had stage I-II disease. Of 497 women followed for pregnancy status, 368 (74.0%) had at least one pregnancy, 317 (63.8%) at least one live birth (365 babies born). At 1638 patient-years (med ian follow-up, 41months), 44 participants experienced a BCFI event, not exceeding the safety threshold. Results suggest that for select young women with early hormone-receptor-positive breast cancer, temporary interruption of endocrine therapy to attempt pregnancy does not confer greater short-term risk of recurrence than a modern control group. Further follow-up data will be critical to inform longer-term safety. .
