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EPITHELIAL OVARIAN CANCER
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Ovarian cancer is the second most common cancer of the female genital tract, with approximately 21,290 cases expected in the United States in 2015 (1). Epithelial tumors comprise 90% of ovarian cancers, and the most common histologic subtype is high-grade serous carcinoma, followed by endometrioid, clear cell, and mucinous tumors. Ovarian cancer remains the number one cause of death due to gynecologic cancers in the United States, accounting for 14,180 deaths this year. Among women, ovarian cancer is the fifth most common cancer-related cause of death in the United States (1). The lifetime risk of a woman in the United States developing ovarian cancer is approximately 1 in 70 (1.37%). Ovarian cancer is also more common among white women compared to African American or Asian American women in the United States, although the differences are narrowing. In most parts of Europe and North America, the incidence of ovarian cancer was constant during the decades prior to the 1990s. However, among white women, ovarian cancer incidence rates are reported to have declined from 2001 to 2010 by 2.2% per year (2).
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This cancer is predominantly a cancer of the perimenopausal and the postmenopausal period, with 80% to 90% of cases occurring after the age of 40. The incidence is higher in older women, and the median age at diagnosis is 63 years.
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Ovarian cancer accounts for 5.5% of the deaths from cancer that occur in women between 60 and 79 years of age (1). Prognosis among women with ovarian cancer is dependent on the stage of disease at the time of diagnosis. Five-year survival rates among women with localized, regional, and distant disease at the time of diagnosis are 92%, 72%, and 27%, respectively (1). Relative survival rates for ovarian cancer have improved substantially over the last decade by an average of 2% per year, and modern 5-year survival estimates are between 45% and 50% (3). Survival among white women with ovarian cancer in the United States is reportedly better than survival among black women, and the improvement noted was not observed in black women (1,4).
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The etiology and the tissue of origin of ovarian cancer are not fully understood. Over the past decade, there has been an increased appreciation that epithelial ovarian cancers (EOCs) represent a heterogeneous group of malignancies. Some of this heterogeneity is related to distinct pathophysiology associated with the development of different histologic subtypes. For example, the majority of high-grade serous ovarian cancers are now believed to arise from fallopian tube fimbria rather than ovarian surface epithelium. This fallopian tube hypothesis originated from observations in women undergoing risk-reducing (prophylactic) salpingo-oophorectomy due to hereditary breast-ovarian cancer syndromes. Approximately 5% to 10% of these women are diagnosed with an ...