INCIDENCE AND PATHOLOGY
Ovarian cancer remains a leading cause of cancer deaths in American women, ranking behind lung, breast, colon, and pancreatic cancers. The ovary is responsible for the hormone and egg production. Between menarche (11–13 years) and menopause (45–55 years), the ovary is responsible for follicle maturation associated with egg maturation, ovulation, and cyclical sex steroid hormone production. These complex biologic functions are linked to stromal and germ cells within the ovary. These cells can be broadly grouped into stromal cells and ovarian germ cells and the enveloping epithelial cells. Malignancies arising in each group include multiple histological variants with unique neoplastic behaviors. Epithelial tumors are the most common histological variant of ovarian neoplasms; they may be benign (50%), frankly malignant (33%), or of borderline malignancy of low malignant potential (16%). In adnexal masses detected by imaging or physical examination, age influences risk of malignancy; tumors in younger women are more likely benign. In the malignant group, the most common tumors are epithelial. In the group of the ovarian epithelial, malignancies are the serous tumors (60–70%); mucinous tumors (10%), endometrioid (10–15%), and clear cell (10–15%), tumors. The distribution of histologic types varies in different parts of the world. Less common stromal tumors arise from the ancillary, supportive cells such as steroid hormone-producing cells and likewise have different phenotypes and clinical presentations. Most stromal tumors do not produce estrogen, but ectopic hormone production can be seen in certain subtypes. Tumors arising in the ovarian germ cell lineage are generally similar in biology and behavior to testicular tumors in males, although their intraperitoneal location alters some metastatic behaviors (Chap. 84). Ovarian tissue may also host metastatic tumors arising from breast, colon, gastric, and pancreatic primaries. Bilateral ovarian masses from metastatic mucin-secreting gastrointestinal cancers are termed Krukenberg tumors. A survey of other potential primaries is commonly required during the diagnostic workup of ovarian masses.
OVARIAN CANCER OF EPITHELIAL ORIGIN
An American woman has ~1 in 72 lifetime risk (1.6%) of developing ovarian cancer, with the majority of affected women developing epithelial tumors. In 2017, 22,440 cases of ovarian cancer with 14,195 deaths are expected in the United States. Sporadic (not familial) epithelial tumors of the ovary have a peak incidence in women in their fifties and sixties, although age at presentation ranges from the third decade to the eighties and nineties. Ovarian cancer risk has been linked to an interactive mixture of epidemiologic, environmental, and genetic factors. Nulliparity, obesity, diet, infertility treatments, and possibly hormone replacement therapy have all been linked to an increase in risk. Protective factors include the use of oral contraceptives, multiparity, tubal ligation, aspirin use, and breast-feeding. Other epidemiologic factors such as the use of perineal talcum agents remain controversial. The mechanisms underlying the various protective factors are largely unknown, but theories include suppression of ovulation, modulation ...