Epithelial Ovarian Cancer and Low Malignant Potential (LMP) Tumors Associated With a Lower Incidence of Second Primary Breast Cancer

Abstract

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.

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).

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.

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.