Is there an association between endometriosis and subsequent breast cancer? A retrospective cohort study from Germany.

PURPOSE: Given the relatively high incidence of both endometriosis and breast cancer, investigating the potential connection between these gynecological diseases is of substantial clinical significance. However, there is no clear consensus in the literature on the extent to which the risk of breast cancer is increased in patients with endometriosis. Therefore, we conducted a large-scale observational study investigating the association between endometriosis and breast cancer risk. METHODS: This study included women aged ≥ 18 years with an initial endometriosis diagnosis from one of 315 office-based gynecologists in Germany between January 2005 and December 2021. Non-endometriosis patients were matched 1:1 to patients with endometriosis based on age, index year, average yearly consultation frequency, and predefined co-diagnoses within 12 months before or on the index date, including obesity and benign breast disorders. The association between endometriosis and the 10-year incidence of breast cancer was studied using Kaplan-Meier curves and log-rank tests. Finally, a univariable Cox regression analysis was conducted to assess the association between endometriosis and breast cancer. RESULTS: Over a follow-up period of up to 10 years, no significant difference was observed between the endometriosis (2.4%) and the matched non-endometriosis group (2.5%) with regard to breast cancer diagnoses. Furthermore, the regression analysis revealed no significant association between endometriosis and subsequent breast cancer. CONCLUSION: In summary, our comprehensive 10-year study involving a substantial sample of women indicates that endometriosis is not significantly associated with an increased risk of subsequent breast cancer.

Germany Endometriosis Pattern Changes; Prevalence and Therapy over 2010 and 2019 Years: A Retrospective Cross-Sectional Study.

Background: The aim of this study was to investigate whether the prevalence and the therapy patterns of endometriosis differ in 2010 and 2019. Materials and Methods: This retrospective cross-sectional study was based on the data from the IQVIA Disease Analyzer database and included women with at least one visit to one of the 136 private gynecologist practices in Germany in 2010 or 2019. The prevalence of endometriosis as well as prevalence of each endometriosis therapy such as Dienogest, other Progestins than Dienogest, and Gonadotropin-Releasing Hormones, was calculated in both years. Results: The present study included 346,249 women documented in 2010 and 343,486 women documented in 2019. The prevalence of endometriosis increased from 0.53% in 2010 to 0.66% in 2019 (P<0.001). The proportion of endometriosis patients treated with Dienogest increased significantly between 2010 and 2019 (18.1 vs. 35.0%). The proportion of women prescribed other Progestins than Dienogest has not significantly changed between 2010 and 2019 (8.4 vs. 8.3%). Gonadotropin-releasing hormones were prescribed only rarely in both 2010 and 2019, with a significant decrease in prescriptions between these two years (3.7 vs. 2.0%). Conclusion: There were significant changes in the prevalence and medical therapeutic patterns of endometriosis in 2010 versus 2019 reflecting changes in therapy guidelines and possibly in diagnostic methods.