Second primary ovarian cancer among women with cancer

PURPOSE: Some studies suggest women with certain types of cancers are at increased risk for ovarian cancer. This study assessed the risk of second primary ovarian cancer among U.S. women who have cancer by anatomic site, age, race, and time since diagnosis of the first primary cancer. METHODS: We analyzed data from SEER cancer registries for women diagnosed with invasive cancer between 1973 and 1996. Person-years were accumulated from 2 months after initial cancer diagnosis to date of ovarian cancer diagnosis, death, loss to follow-up, or end of follow-up, December 31, 1996. The expected number of cases was obtained by multiplying 5-year age and calendar year interval specific ovarian cancer rates by the accumulated person-years at risk. We calculated the risk (observed [O]/expected numbers [E]) of second primary ovarian cancer by cancer site and age (<50 years, greater-or-equal, slanted50 years), race (all, white, black), and time since first cancer (0–4, 5–9, 10–14, 15–24 years). Statistical tests and 95% confidence intervals (CI) were based on the assumption of a Poisson distribution. RESULTS: A significant increased risk of ovarian cancer was found for women aged <50 years at time of diagnosis with melanoma (O/E = 3.5, 95% CI = 2.1–5.5) and cancer of the breast (O/E = 6.0, 95% CI = 4.9–7.2), cervix (O/E = 4.2, 95% CI = 2.6–6.3), corpus uteri (O/E = 11.91, 95% CI = 7.3–18.4), colon (O/E = 17.9, 95% CI = 11.1–27.3), and ovary (O/E = 4.9, 95% CI = 2.7–8.2); no increased risk was found for women aged greater-or-equal, slanted50 years. Ovarian cancer risk remained elevated following all of these first primary cancers 5–9 years after diagnosis; for women with breast and colon cancer, risk remained elevated 15–24 years after diagnosis. A significant increased risk was found for all of these cancers among white women <50 years at diagnosis; risk was increased among black women <50 years with cancer of the breast, cervix, and colon. CONCLUSIONS: We found an ovarian cancer risk higher than expected for women with certain types of cancer; however, the risk was limited to women <50 years of age.