No Increased Risks for Pregnancy and Fetal Outcomes
Although women using ART had slightly higher miscarriage rates (11.3% versus 8.8%) and lower rates of induced abortion (0.9% versus 8.3%) than women with spontaneous conceptions, the analysis revealed no statistically significant differences in the frequency of pregnancy complications, delivery complications, or congenital abnormalities between those who received ART and those who conceived naturally.
Dr. Lambertini explained that variations in baseline characteristics, such as age, may have contributed to differences in miscarriage rates.
“Patients in the ART group tended to be older at the time of conception, with a median age of 37.1 years, compared with 34.3 years in the spontaneous pregnancy group,” he said, during his presentation. Women in the ART group also more frequently had hormone receptor–positive breast cancer (43.4% versus 30.8%) and longer median time from diagnosis to conception (4.2 versus 3.3 years).
No Adverse Effects on Breast Cancer Prognosis
At a median follow-up of 5.2 years from conception, there was no detrimental effect of ART on disease-free survival for carriers of pathogenic BRCA1/2 variants who were treated for breast cancer. The ART group showed 13 (13.1%) recurrence events, compared with 118 (27.1%) recurrences in the spontaneous pregnancy group (adjusted hazard ratio, 0.72; 95% CI, 0.38-1.33; P = .147).
“The risk of cancer recurrence was comparable between those using and not using ART to become pregnant after their breast cancer diagnosis and treatment, and the small number of recurrence events in the ART group mostly involved locoregional recurrences,” Dr. Lambertini noted during his talk.
Moreover, breast cancer–specific survival and overall survival appeared to be similar between the two groups, although the small number of deaths precluded the conduction of formal analysis.
“These survival data suggest that utilizing ART does not appear to negatively impact the prognosis or course of the underlying breast cancer,” Dr. Lambertini said during the discussion.
Clinical Implications and Future Work
According to Dr. Lambertini, these results are incredibly valuable for clinicians counseling young breast cancer survivors with pathogenic BRCA1/2 mutations who wish to have biological children.
“Given the interest of patients in having their own family and for some of them in avoiding the transmission of the BRCA1/2 pathogenic variants, our results are critical in improving the oncofertility counseling of young women with breast cancer,” said Dr. Lambertini during his presentation. “We can reassure patients that pursuing ART does not appear to worsen their cancer prognosis or compromise pregnancy outcomes compared to spontaneous conceptions.”
During her discussion session, Dr. Tsang echoed the clinical implications of these findings, emphasizing that, by incorporating this evidence into clinical practice, healthcare providers can better support patients in making informed choices regarding fertility preservation and family planning after cancer treatment.
“Though this study is [retrospective] with a relatively small number, these real-world findings make a major contribution to our limited evidence base on ART safety for cancer survivors carrying BRCA1/2 mutations,” she said.
She cautioned, however, that there remain several unanswered questions and uncertainties. “We need prospective data with a larger sample size to confirm the safety of ART in this population, as well as studies to assess whether different types of ART have different safety profiles.”
Dr. Lambertini concluded his talk by saying, “While waiting for prospective studies to confirm our results, fertility preservation at diagnosis of early breast cancer should be offered to all women interested in future fertility, including BRCA carriers.”
Dr. Lambertini reported financial relationships with Roche, AstraZeneca, Lilly, Novartis, Pfizer, Exact Sciences, MSD, Seagen, Gilead, Pierre Fabre, and Menarini (consulting or advisory roles); Takeda, Roche, Lilly, Novartis, Pfizer, AstraZeneca, Sandoz, Ipsen, Libbs, Knight, Dalichi Sankyo, Gilead, Menarini (honoraria); Gilead, Daiichi Sankyo, and Roche (travel support); and Gilead (research funding to the institution). Dr. Tsang reported financial relationships with AstraZeneca, Amgen, Daichi Sankyo, Eisai, Gilead, Lilly, Lucence, Novartis, Pfizer, and Veracyte (honoraria); De Novo (consulting or advisory roles); and Pfizer (grant panel reviewer).