Risk of Subsequent Ovarian Cancer after Ovarian Conservation in Young Women with Stage i Endometrioid Endometrial Cancer

OBJECTIVE: To examine the cumulative incidence of subsequent ovarian cancer among young women with stage I endometrioid endometrial cancer who had ovarian conservation at surgical treatment. METHODS: This retrospective study examined the Surveillance, Epidemiology, and End Results Program to identify women aged younger than 50 years who underwent hysterectomy with ovarian conservation for stage I endometrioid endometrial cancer between 1983 and 2013. Time-dependent risk of ovarian cancer diagnosed during the follow-up after endometrial cancer diagnosis was examined. RESULTS: Among 1,322 women in the study cohort, 16 women developed subsequent ovarian cancer with 5- A nd 10-year cumulative incidences of 1.0% and 1.3%, respectively. Median time to develop subsequent ovarian cancer was 2.4 years, and the majority of subsequent ovarian cancer was diagnosed within the first 3 years from the diagnosis of endometrial cancer (68.8%). The majority of subsequent ovarian cancer was endometrioid type (81.3%) and stage I disease (75.0%). With a median follow-up time of 11.6 years, there were no ovarian cancer deaths. Younger age at endometrial cancer diagnosis was significantly associated with increased risk of subsequent ovarian cancer (10-year cumulative incidences: Age younger than 40 compared with 40-49 years, 2.6% compared with 0.4%, hazard ratio 5.00, 95% confidence interval [CI] 1.60-15.7, P=.002). CONCLUSION: Young women with stage I endometrioid endometrial cancer have an approximately 1% risk of developing subsequent ovarian cancer after ovarian conservation at the time of hysterectomy that was associated with favorable tumor factors resulting in good ovarian cancer-specific survival. Our results endorse the importance of genetic testing and close follow-up when counseling about this procedure, especially for those who are younger than 40 years.