Decreasing Trends of Secondary Primary Colorectal Cancer among Women with Uterine Cancer: A Population-Based Analysis

The current study examined trends, characteristics, and outcomes of women with uterine cancer who had secondary colorectal cancer. This is a retrospective study utilizing the Surveillance, Epidemiology, and End Results Program between 1973-2013. Among uterine cancer (n = 246,272) and colorectal cancer (n = 421,312) cohorts, women with both diagnoses were identified, and clinico-pathological factors and survival were extracted and analyzed. There were 6862 women with both cancer diagnoses, representing 2.8% of the uterine cancer cohort and 1.6% of the colorectal cancer cohort. Among 123,940 women with uterine cancer survivors, the number with postcedent colorectal cancer decreased from 5.3% to 0.7% between 1981-2008 (relative risk reduction 87.0% p < 0.001). Similarly, of 141,801 women with colorectal cancer survivors, the number with postcedent uterine cancer decreased from 1.7% to 0.5% between 1973-2008 (relative risk reduction 71.6%, p < 0.001). In the uterine cancer cohort, women with antecedent/synchronous colorectal cancer had more high-grade tumors and advanced-stage disease resulting in poorer survival, whereas those who had postcedent colorectal cancer had more low-grade tumors and early-stage disease resulting in superior survival compared to those without secondary colorectal cancer (all, p < 0.05). In conclusion, the development of postcedent colorectal cancer following uterine cancer has decreased in recent years in the United States.