|The following article is part of conference coverage from the 17th St. Gallen International Breast Cancer Symposium, which is being held virtually from March 7-21, 2021. The team at Cancer Therapy Advisor will be reporting on the latest research conducted by leading experts in breast cancer. Check back for more from the 17th St. Gallen International Breast Cancer Symposium.|
Young breast cancer survivors were found to be at increased risk for infertility and premature menopause relative to patients without cancer independent of chemotherapy, according to research presented at the 17th St. Gallen International Breast Cancer Conference 2021.
Moira Rushton, MD, from the University of Ottawa in Canada, and colleagues conducted a retrospective, population-based, matched-cohort study of women aged 15 to 39 who were diagnosed with early-stage (I-III) breast cancer from 1995 to 2014. The patients were categorized into 2 groups based on whether they had received cytotoxic chemotherapy and were then matched with 5 noncancer control groups by year of birth and census subdivision.
Outcomes were recorded more than 12 months after breast cancer diagnosis and included infertility, pregnancy, and premature menopause, which was defined as menopause before age 40.
The analysis included 3903 patients with breast cancer and 19,515 noncancer patients. A total of 850 patients were in the no-chemotherapy group, 3053 were in the chemotherapy group, and 19,515 were in the control group. The median age at breast surgery was 36 years (interquartile range, 33-38); 60.3% of individuals in the control group were nulliparous compared with 47.3% of patients with breast cancer who received chemotherapy and 59.9% of those who did not.
Compared with patients without cancer, women with breast cancer had a higher risk of infertility diagnosis and premature menopause, as well as a lower probability of pregnancy. Patients with breast cancer who were treated with or without chemotherapy had an increased risk of infertility, premature menopause, and early menopause.
Among women with breast cancer and no chemotherapy, the relative risk (RR) was 1.80 for infertility, 0.90 for pregnancy, and 2.12 for premature menopause, compared with women in the control group. Patients with breast cancer and chemotherapy had a RR of 1.81 for infertility, 0.85 for pregnancy, and 6.25 for premature menopause, compared with women in the control group.
In addition, age at diagnosis was protective against infertility and premature menopause, and prior parity was associated with a lower risk of infertility compared with nulliparous women but had no effect on pregnancy.
“Our results demonstrate that all young breast cancer survivors face an increased risk of infertility and premature menopause relative to noncancer patients independently of chemotherapy,” the researchers commented. “Breast cancer survivors treated with chemotherapy have a significantly lower chance of pregnancy compared to noncancer patients. These results emphasize the importance of pre-treatment fertility counseling for young women diagnosed with breast cancer.”
The investigators noted that their findings have limitations because they could not obtain data regarding estrogen and progesterone receptors and HER2 status, as well as receipt of endocrine therapy in the cohort. They advise that further research is needed to “distill the risks associated with modern treatment approaches and in breast cancer subtypes.”
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Rushton M, Pudwell J, We S, et al. Reproductive outcomes in young breast cancer survivors treated (15-39) in Ontario, Canada: a population-based study. Presented at: 17th St Gallen International Breast Cancer Conference 2021; March 17-20, 2021. Abstract P152.