Fertility preservation (FP) significantly increases the rate of live birth after breast cancer treatment without adversely affecting overall survival, suggest findings from a nationwide study published in JAMA Oncology.
“These results indicate generally reassuring long-term reproductive outcomes in women diagnosed with [breast cancer] during their reproductive years but also highlight the importance of FP counseling in this population”, say Kenny Rodriguez-Wallberg, from Karolinska Instituet in Stockholm, Sweden, and co-authors.
The team writes that “successful pregnancy after [breast cancer] was possible” for patients who did and did not undergo FP but the likelihood of live birth increased with use of cryopreservation of oocytes and embryos after controlled ovarian stimulation.
The Swedish cohort included 425 breast cancer patients who underwent FP between 1994 and 2017 and an age-, county- and calendar-matched group of 850 women with breast cancer who did not receive FP care.
Women who underwent FP were younger than those who did not (mean 32.1 vs 33.3 years) and less likely to have ever been pregnant before their breast cancer diagnosis (71.1 vs 20.1% nulliparous). The FP group was also more likely to have oestrogen-positive breast cancer (68.0 vs 60.6%) and to be given chemotherapy (93.9 vs 87.7%).
Overall, 22.8% of the women who received FP had at least one live birth after breast cancer diagnosis over an average 4.6 years of follow-up, as did 8.7% of those patients who did not undergo FP, over an average of 4.8 years.
This resulted in a significantly higher live birth rate after breast cancer in the FP group, with a hazard ratio (HR) of 2.3 versus the no FP group, after adjusting for a raft of breast cancer and sociodemographic factors.
Specifically, the 5- and 10-year cumulative rates of live birth after breast cancer were 19.4% and 40.7%, respectively, in the FP cohort, versus 8.6% and 15.8% among the control group.
And FP was associated with a higher rate of women having more than one live birth (37.3 vs 17.7%).
Kenny Rodriguez-Wallberg et el also found that, after a median 4.9 years of follow-up, assisted reproductive technology was more commonly used by the FP group after breast cancer, with an adjusted HR of 4.8.
Moreover, the rate of all-cause mortality was significantly lower in the FP group than the controls, with an adjusted HR of 0.4.
After a median 5.8 years of follow-up, the cumulative 5- and 10-year rates of death in the FP cohort were 5.3% and 13.8%, respectively, compared with corresponding rates of 11.1% and 23.2% in the control group.
The researchers admit that disease-specific and disease-free survival were not investigated in the study and that there could have been a “selection bias”, where women who chose to undergo FP may have been more likely to have a good prognosis than those who did not.
“Whether the proposed healthy FP effect indeed exists, and whether FP is associated with disease-free survival, should be further investigated in large studies of FP safety in the setting of [breast cancer] in young women”, they recommend.
Marklund A, Lundberg FE, Eloranta S, et al. Reproductive outcomes after breast cancer in women with vs without fertility preservation. JAMA Oncol; Advance online publication 19 November 2020. doi:10.1001/jamaoncol.2020.5957.