ABSTRACT
OBJECTIVES: Differences in the clinical characteristics of ovarian tumors of low malignant potential (LMP) and ovarian cancer have suggested divergences in tumor biology. The aim of this population-based study was to compare the risk of a second primary breast cancer after a history of either an LMP tumor or an epithelial ovarian cancer. METHODS: Breast cancers were evaluated among 3297 women with a history of LMP tumors, and 45,986 women with a history of epithelial ovarian cancer, within the Surveillance, Epidemiology, and End Results (SEER) Program. The expected incidence of breast cancer was then determined as a function of year, age, race, and geographic location, and combined with the observed incidence to derive the standardized incidence ratio (SIR). RESULTS: Forty-one (1.2%) patients with an LMP history were diagnosed with breast cancer, where 56.8 cases were expected, for an SIR of 0.72 [95% confidence interval (CI) 0.52-0.98]. Similarly, 734 patients (1.6%) with a history of ovarian cancer were diagnosed with breast cancer, where 809 were expected, for an SIR of 0.91 (95% CI 0.84-0.98). Overall, LMP patients were younger and had a shorter time between diagnoses. LMP patients also had a significantly lower relative risk of developing second primary breast cancers. CONCLUSION: Patients with a history of having either an LMP tumor or an epithelial ovarian cancer have a less than expected risk of subsequent breast cancer. Patients with LMP tumors are at lower risk than patients with a history of ovarian cancer for the development of these second malignancies.
