Second primary ovarian cancer among women diagnosed previously with cancer.

This study assessed the risk of second primary ovarian cancer among United States women diagnosed previously with invasive cancer. We analyzed data from cancer registries participating in the Surveillance, Epidemiology, and End Results program for women diagnosed with invasive cancer between 1973 and 1996. We calculated the risk [observed (O)/expected numbers (E)] of second primary ovarian cancer by cancer site and age at diagnosis of first primary cancer (<50 years and > or =50 years), race (all, white, and black), and years since first cancer (0-4, 5-9, 10-14, and 15-24 years). Statistical tests and 95% confidence intervals (CI) assumed a Poisson distribution. A significantly increased risk of ovarian cancer was found for women who were aged <50 years at diagnosis with melanoma (O/E = 3.5, 95% CI = 2.1-5.5) or 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 = 11.9, 95% CI = 7.3-18.4), colon (O/E = 17.9, 95% CI = 11.1-27.3), or ovary (O/E = 4.9, 95% CI = 2.7-8.2). No increased risk was found for women aged > or =50 years. Ovarian cancer risk remained elevated after these first primary cancers 5-9 years after diagnosis; for breast and colon cancer, risk remained elevated 15-24 years after diagnosis. Women > or =50 years at diagnosis with melanoma or cancer of the cervix, corpus uteri, ovary, rectum, or lung and bronchus were at a decreased risk for second primary ovarian cancer. Ovarian cancer risk is higher than expected for women who were diagnosed with certain types of cancer at <50 years of age.