Results from a new investigation support the safety of fertility preservation in women with breast cancer.
The cohort study concluded that fertility preservation – with or without hormonal stimulation – was not associated with increased risk of relapse or disease-specific mortality in these women. The investigators said the findings may ultimately change health care practice for the benefit of women with breast cancer who wish to preserve their fertility.
Reporting in JAMA Oncology, the team of Swedish clinicians behind the research explained that although breast cancer is the most common indication for fertility preservation in women of reproductive age, there is a lack of data assessing the association between the use of hormonal stimulation for fertility preservation and potential deterioration in breast cancer prognosis.
“The aim of this cohort study was to investigate the long-term safety of fertility preservation with and without hormonal stimulation in a large Swedish nationwide cohort of young women with breast cancer by comparing disease-specific mortality and relapse rates in women who had undergone fertility preservation at the time of their breast cancer diagnosis with women who had not,” the authors wrote.
The nationwide study comprised 1275 women (mean age 32.9 years), all of whom had been diagnosed with breast cancer between 1994 and 2017. Of these, 425 women had undergone fertility preservation. These individuals were compared with 850 breast cancer patients (matched by age, period of diagnosis, and region) who had not undergone fertility preservation. The researchers also assessed relapse-free survival in a sub-cohort of 241 women with complete data who underwent fertility preservation and 482 women who did not. The study’s primary outcome was disease-specific mortality; its secondary endpoint was any event of death due to breast cancer or relapse (local, regional, or systemic recurrence).
According to primary author Anna Marklund, MD, PhD, of the Karolinska Institute in Solna, Sweden, death due to breast cancer occurred in 17 women who underwent hormonal fertility preservation, 7 who underwent non-hormonal fertility preservation, and 80 who were unexposed to fertility preservation. The 10-year breast cancer-specific survival rate was 88% in the group that underwent hormonal fertility preservation, 90% in the group that underwent non-hormonal fertility preservation, and 81% in the unexposed group. The 10-year relapse-free survival rate were 82%, 80%, and 73%, respectively, in these three groups.
After adjusting for a number of potential confounding variables, disease-specific mortality was found to be statistically similar in women who underwent hormonal fertility preservation (adjusted HR=0.59; 95% CI, 0.32-1.09), those who underwent non-hormonal fertility preservation (adjusted HR=0.51; 95% CI, 0.20-1.29), and women who were not exposed to fertility preservation (reference).
Similarly, in the sub cohort of 723 patients with detailed relapse data available, the adjusted rate of disease-specific mortality and relapse were also found to be similar among women who underwent hormonal fertility preservation (adjusted HR=0.81; 95% CI, 0.49-1.37), those who underwent non-hormonal fertility preservation (adjusted HR=0.75; 95% CI, 0.35-1.62), and those were not exposed to fertility preservation (reference).
These findings, the investigators concluded, help demonstrate the safety of fertility preservation procedures in women with breast cancer.
“Women diagnosed with breast during their reproductive years should be referred, when interested, for fertility counseling and provided with the available information on safety of the procedures that are offered,” the authors wrote.
Future research on the subject, they added, should ideally include even longer follow-up.
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