Epithelial Tumors of the Ovary

Abstract

Worldwide, ovarian cancer is the seventh most common cancer in women and the eighth most common cause of cancer death. There are about 239,000 new cases and 152,000 deaths annually (American Cancer Society 2015). In the Western hemisphere, ovarian cancer accounts for 4% of cancer in women and is the most frequent cause of death due to gynecological cancer. In American women, ovarian cancer represents 3% of all new cancers (SEER 2017). It ranks 11th in incidence and 5th in mortality and accounts for 5% of cancer deaths. It is estimated that in the USA in 2017, there are 22,440 new ovarian cancer cases and 14,080 deaths, making it the most lethal gynecologic malignancy (Siegel et al. 2017). Approximately 1.3% of American women will develop ovarian cancer in their lifetime, or 12 new cases per 100,000. In general, the disease is more common in industrialized countries where parity is lower, but there are notable exceptions such as Japan which has a low parity and low rate of ovarian cancer. The lifetime risk varies widely from 0.45% in Japan to 1.7% in Sweden. Annual incidence rates of ovarian cancer are lower in developing countries as compared to developed countries, averaging 5.0 and 9.1 per 100,000, respectively. Similarly, mortality rates average 3.1 and 5.0 per 100,000, respectively (American Cancer Society 2015). Denmark and other Scandinavian countries have among the highest annual incidence rates at greater than 16 per 100,000 women. Interestingly, as compared to all other common cancers, ovarian cancer varies the least in age-standardized incidence rates across registry populations worldwide (Bray et al. 2015). In the USA, incidence and mortality rates have been declining by 1.9% and 2.2% per year, respectively, from 2004 to 2013 (SEER 2017). Over longer periods, the incidence has been relatively stable worldwide from the 1970s to the 2000s. There have been, however, small but significant increases in Eastern and Southern Europe and Asia and decreases in Northern Europe and North America (Coburn et al. 2017). In addition, the incidence of ovarian carcinoma appears to have decreased as peritoneal and tubal carcinomas have increased, reflecting a recent change in classification. Migration studies have shown that ovarian cancer rates approach those of the place of immigration rather than the place of emigration, suggesting a significant environmental component to ovarian cancer risk.