Ovarian Cancer (Epithelial)

Synonyms/Description

Ovarian carcinoma or adenocarcinoma

Etiology

Ovarian cancer is the second most common (endometrial is number one) genital tract malignancy (1% to 2% lifetime risk) and the most deadly (overall 5-year survival of 45%). Familial predisposition accounts for 5% to 10% of women who develop ovarian cancer and is typically associated with BRCA1 and BRCA2 gene mutations. Ovarian cancer is more prevalent with increasing age, usually occurring in postmenopausal women. Most cancers are of the epithelial type, the most common of these being serous cystadenocarcinoma (greater than 50%); the cell type comprising this tumor is very similar to that found in the fallopian tubes. Endometrioid adenocarcinoma (15% to 20% of epithelial ovarian cancers) and clear cell tumors of the ovary (6% of epithelial tumors) are associated with pelvic endometriosis and tend to occur in younger women. Mucinous adenocarcinoma (5% to 10% of epithelial tumors) is a mucin-producing tumor and resembles the intestinal or endocervical cell types. Other rarer cell types include carcinosarcoma (epithelial and mesenchymal mixed tumor), transitional cell, squamous cell carcinoma, and Brenner tumors (see related sections elsewhere in the book).

Traditionally, ovarian cancer was thought to arise de novo from the surface epithelium (mesothelium) of the ovary. However, there is recent evidence that the most common ovarian cancer originates from the fallopian tube. This precursor lesion, called serous intraepithelial tubal carcinoma (STIC), is very similar to high-grade ovarian serous carcinoma. The current theory is that most of these tumors arise from a STIC in the fimbriated end of the fallopian tube then spread to the ovary.

Even when the ovaries have been removed, a patient can still develop primary peritoneal carcinoma. This entity, known as serous surface papillary carcinoma of extra-ovarian origin, is considered a very aggressive cancer.