Cancer
The Prospective Association between Endometriosis and Colorectal Cancer in the Sister Study Isabella Caruso* Isabella Caruso Katie O’Brien Katherine Reeves
Background: Endometriosis is a painful and chronic inflammatory disease characterized by the growth of endometrial-like tissue outside of the uterus. Individuals with endometriosis are more likely to have coexisting chronic conditions, including cancer, autoimmune diseases, asthma diseases, and cardiovascular diseases. Inflammation may be an important component of both colorectal cancer progression and the pathogenesis of endometriosis. However, the association between endometriosis and colorectal cancer remains inconclusive.
Methods: We evaluated the association between endometriosis and colorectal cancer among 50,357 participants enrolled in the Sister Study. The Sister Study is a long-term prospective cohort study that enrolled women aged 35 to 74 in the United States, including Puerto Rico, between the years 2003 and 2009, whose sisters were diagnosed with breast cancer. Data were gathered through self-reporting at baseline and subsequent follow-up questionnaires. Cox proportional hazards analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between endometriosis and colorectal cancer.
Results: Overall, 7,740 participants in the study had a baseline diagnosis of endometriosis and 1,247 participants were diagnosed during follow-up. In addition, 339 participants had an incident diagnosis of colorectal cancer. In the age-adjusted model, we did not observe associations between endometriosis and colorectal cancer (adjusted HR 0.96 95% CI 0.81-1.14).
Conclusions: This study will substantially contribute to the current literature on endometriosis by incorporating a large prospective analysis with several important covariates to address potential confounding. The age-adjusted results do not provide support for a relationship between endometriosis and colorectal cancer. More research is needed to fully understand the root cause of endometriosis and how it may contribute to increased inflammation in the body.