Mucinous Ovarian Carcinoma

Ovarian cancer (OC) is the seventh most commonly diagnosed cancer among women in the world and the tenth most common in China. Epithelial OC is the most predominant pathologic subtype, with five major histotypes that differ in origination, pathogenesis, molecular alterations, risk factors, and prognosis. Genetic susceptibility is manifested by rare inherited mutations with high to moderate penetrance. Genome-wide association studies have additionally identified 29 common susceptibility alleles for OC, including 14 subtype-specific alleles. Several reproductive and hormonal factors may lower risk, including parity, oral contraceptive use, and lactation, while others such as older age at menopause and hormone replacement therapy confer increased risks. These associations differ by histotype, especially for mucinous OC, likely reflecting differences in etiology. Endometrioid and clear cell OC share a similar, unique pattern of associations with increased risks among women with endometriosis and decreased risks associated with tubal ligation. OC risks associated with other gynecological conditions and procedures, such as hysterectomy, pelvic inflammatory disease, and polycystic ovarian syndrome, are less clear. Other possible risk factors include environmental and lifestyle factors such as asbestos and talc powder exposures, and cigarette smoking. The epidemiology provides clues on etiology, primary prevention, early detection, and possibly even therapeutic strategies.

Advances over the past decade suggest a need to reassess the distribution of ovarian surface epithelial tumors. A series of 220 consecutive invasive ovarian carcinomas, including carcinosarcomas and peritoneal carcinomas, was reviewed. Notable findings include: 7% of tumors were carcinosarcomas; 22% of cases of peritoneal serous carcinomatosis were of peritoneal origin; <3% of cases were mucinous carcinomas; and only one malignant Brenner tumor (0.5%) and no pure transitional cell carcinomas were identified. If peritoneal carcinomas, carcinosarcomas, and mixed carcinomas with a serous component are combined with serous carcinomas, this group accounts for 78% of all cases and 87% of advanced stage cases, suggesting a greater uniformity to epithelial ovarian cancer than previously appreciated.

The understanding of ovarian cancer pathogenesis has recently shifted to recognize distinct changes in how ovarian cancer histotypes are defined. Using the 2014 World Health Organization (WHO) diagnostic guidelines, we classified ovarian cancer histotypes in Surveillance, Epidemiology, and End Results (SEER) cancer registry data and examined survival patterns by histotype and disease stage.