Of all the gynecologic cancers, ovarian malignancies represent the greatest clinical challenge because they have a high mortality. Epithelial cancers are the most common ovarian malignancy, and over two-thirds of patients have advanced disease at diagnosis. Ovarian cancer represents a major surgical challenge, and optimal therapy includes surgical debulking followed by platinum-based combination chemotherapy. It has the highest fatality-to-case ratio of all the gynecologic malignancies. There are nearly 22,000 new cases annually in the United States, and 15,460 women can be expected to succumb to their illness (1). Ovarian cancer is the seventh most common cancer in women in the United States, accounting for 3% of all malignancies and 6% of deaths from cancer in women and almost one-third of invasive malignancies of the female genital organs. Ovarian cancer is the fifth most common cause of death from malignancy in women. A woman’s risk at birth of having ovarian cancer at some point in her lifetime is 1% to 1.5% and that of dying from ovarian cancer is almost 0.5% (2).
Approximately 90% of ovarian cancers are derived from the coelomic epithelium or mesothelium (2). The cells are a product of the primitive mesoderm, which can undergo metaplasia. A classification of the histologic types of epithelial tumors of the ovary is presented in Table 37.1. Neoplastic transformation can occur when the cells are genetically predisposed to oncogenesis or exposed to an oncogenic agent or both (3).
Table 37.1 Epithelial Ovarian Tumors
I. Serous Endosalpingeal
A. Benign
B. Borderline
C. Malignant
II.
Mucinous Intestinal, Endocervical
A.
B.
C.
III.
A.
B.
C.
IV.
A.
B.
C.
V. Brenner Transitional
A. Benign
B. Borderline (proliferating)
C. Malignant
VI.
A.
B.
C.
VII. Undifferentiated May be anaplastic
VIII. Unclassified
From Seroy SF, Scully RE, Sobin LH. International histological classification of tumours no. 9. Histological typing of ovarian tumors. Geneva, Switzerland: World Health Organization, 1973, with permission.
pattern that resembles epithelium in the lower genital tract (3). For example, serous tumors have an appearance similar to that of the glandular epithelial lining of the fallopian tube, endometrioid tumors resemble proliferative endometrium, and clear cell tumors resemble secretory or gestational endometrium. Mucinous tumors may contain cells that resemble endocervical glands, but more commonly these cells resemble the gastrointestinal epithelium. Transitional (Brenner) tumors are so named because of a resemblance to the epithelium in Walthard rests and bladder urothelium.