Epidemiology of low-grade serous ovarian cancer

OBJECTIVE: The objective of the study was to determine whether the epidemiology of low-grade ovarian serous cancers is distinct from that of high-grade ovarian serous cancers. STUDY DESIGN: The National Cancer Institute's Surveillance Epidemiology and End Results ( SEER) program reports incidence, and survival, data from representative population based cancer registries. The SEER data are analyzed to compare the descriptive epidemiologies of low-and high-grade lesions. RESULTS: Mean survival ( 99 vs 57 months) and age (55.5 vs 62.6 years) trends in annual incidence rate (-3.8% vs 1.4%), rate ratio of advanced to early disease (1.9 vs 10.2), rate ratio of post-to premenopausal incidence (5.0 vs 13.0). and difference in average age between advanced and early stage (none vs 2.5 years) are significantly different for patients with low-grade, compared with high-grade, disease. CONCLUSION: Epidemiology of low-grade tumors appears sufficiently different from that of high-grade lesions to support the concept that low-grade ovarian serous cancers constitute a distinct clinical, and perhaps biologic, entity.