Breastfeeding may lower ovarian cancer risk ‘beyond’ pregnancy alone
Click Here to Manage Email Alerts
Healio spoke with Naoko Sasamoto, MD, MPH, from the Obstetrics and Gynecology Epidemiology Center, Brigham and Women’s Hospital, Harvard Medical School, about her JAMA Oncology study that suggested breastfeeding as a potentially modifiable factor that may decrease risk for ovarian cancer independent of pregnancy alone – and what this means for clinicians.
Healio: Before this study, what did the research say about the link between breastfeeding and ovarian cancer risk?
Sasamoto: Ovarian cancer is rare; however, most cases are diagnosed at a late stage when 5-year survival is less than 50%. Consequently, identifying factors that influence ovarian cancer risk is key to improving the impact of this disease. Prior studies suggested that breastfeeding may decrease ovarian cancer risk, but their findings were inconsistent.
Healio: What are the associations between breastfeeding and epithelial ovarian cancer risk overall and by histotype?
Sasamoto: We conducted the largest study to date to examine the association between breastfeeding and ovarian cancer risk using data from the international Ovarian Cancer Association Consortium. Our study showed that ever having breastfed was associated with a 24% reduced risk for invasive epithelial ovarian cancer overall. Among invasive tumors, ever having breastfed was associated with a 25% reduced risk for high-grade serous, 27% reduced risk for endometrioid, and 22% reduced risk for clear cell tumors.
Healio: What new information did this study yield?
Sasamoto: Our study showed that ever having breastfed was associated with a 24% reduced risk for ovarian cancer, including the high-grade serous type that is the most common and deadly subtype. Importantly, this benefit extends beyond any benefit of pregnancy alone. Interestingly, average duration of breastfeeding of less than 3 months was associated with significant reduction in risk, suggesting that even a short duration of breastfeeding may be beneficial in reducing ovarian cancer risk.
Healio: What were the limitations of the study?
Sasamoto: Our results show that breastfeeding is associated with reduced ovarian cancer risk, but do not provide data on the underlying biologic mechanisms. There are several hypotheses on how breastfeeding might lead to lower risk for ovarian cancer, but the exact biological mechanisms of how breastfeeding may impact ovarian cancer risk is not well understood. What our results do tell us is that the reduction in ovarian cancer risk extends beyond any benefit of pregnancy alone and that even a short duration of breastfeeding, as little as 1 to 3 months, can help reduce ovarian cancer risk.
Healio: How might future research overcome these limitations?
Sasamoto: Our next research steps are to examine this association using prospective studies and to further investigate, both in observational as well as in experimental studies, the underlying biological mechanism.
Healio: What is the take-home message for clinicians treating patients with ovarian cancer?
Sasamoto: Our study showed that ever having breastfed was associated with a reduced risk for ovarian cancer, including the high-grade serous type that is the most common and deadly subtype. Importantly, this benefit extends beyond any benefit of pregnancy alone. Interestingly, our results also suggested that even a short duration of breastfeeding may be beneficial in reducing ovarian cancer risk. While replication of our findings is necessary, we believe our findings add to the list of health benefits of breastfeeding.
References:
Babic A, et al. JAMA Oncol. 2020;doi:10.1001/jamaoncol.2020.0421.
Collapse
Click Here to Manage Email Alerts