medwireNews: A nationwide study of Swedish breast cancer patients has demonstrated that receipt of fertility preservation (FP) significantly improves reproductive outcomes compared with the absence of such care.
“[A]lthough successful pregnancy after [breast cancer] is possible both in women with and without FP, FP is associated with significantly higher rates of post-[breast cancer] live births and use of ART [assisted reproductive technology] treatments, without any deleterious association with all-cause survival,” the investigators report in JAMA Oncology.
Kenny Rodriguez-Wallberg (Karolinska Instituet, Stockholm, Sweden) and colleagues collated information for 425 women who received FP between 1994 and 2017, such as controlled ovarian stimulation to allow cryopreservation of oocytes or embryos, and 850 women matched by age, county, and calendar period who did not.
The researchers note that use of FP was associated with younger age (mean 32.1 vs 33.3 years) and being nulliparous (71.1 vs 20.1%), as well as a diagnosis of estrogen-positive breast cancer (68.0 vs 60.6%) and receipt of chemotherapy (93.9 vs 87.7%).
At least one live birth after breast cancer diagnosis was reported for 22.8% of the FP cohort and 8.7% of controls over an average 4.6–4.8 years of follow-up, giving a significant hazard ratio (HR) of 2.3 in favor of FP use, after considering breast cancer-related and sociodemographic confounding factors.
The cumulative 5-year rates of live birth in the FP and control cohorts were 19.4% and 8.6%, respectively, rising to 40.7% and 15.8% after 10 years, the team reports, with FP recipients significantly more likely to have had more than one live birth (37.3 vs 17.7%).
Over an average 4.9 years of follow-up, women who received FP were 4.8 times more likely to have used ART than controls, after adjusting for confounding factors.
In addition, overall survival analysis indicate that the all-cause mortality rate was significantly lower for women who did versus did not receive FP, with an adjusted HR of 0.4.
The cumulative 5-year rates of death after an average 5.8 years of follow-up were 5.3% with FP care versus 13.8% without FP care, with 10-year rates of 11.1% and 23.2%, respectively.
However, the researchers acknowledge that the study is limited by lack of data on disease-free or disease-specific survival endpoints.
They recommend further research is required to rule out a “plausible” FP selection bias contribution to survival outcomes, where “women who prefer to undergo FP treatments could appreciate their disease as transitory with good chances of survival, whereas other women, more affected by the disease, could have chosen to skip additional medical procedures.”
Nevertheless, Rodriguez-Wallberg et al conclude: “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.”
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JAMA Oncol; doi:10.1001/jamaoncol.2020.5957