After a prophylactic oophorectomy, a small percentage of women may develop a primary peritoneal carcinoma, similar in appearance to ovarian cancer. The prognostic information presented below deals only with epithelial carcinomas. Stromal and germ cell tumors are relatively uncommon and comprise less than 10% of cases. (Refer to the PDQ summaries on Ovarian Germ Cell Tumor Treatment and Ovarian Low Malignant Potential Tumor Treatment for more information.)
Ovarian cancer usually spreads via local shedding into the peritoneal cavity followed by implantation on the peritoneum and via local invasion of bowel and bladder. The incidence of positive nodes at primary surgery has been reported to be as much as 24% in patients with stage I disease, 50% in patients with stage II disease, 74% in patients with stage III disease, and 73% in patients with stage IV disease. In this study, the pelvic nodes were involved as often as the para-aortic nodes. Tumor cells may also block diaphragmatic lymphatics. The resulting impairment of lymphatic drainage of the peritoneum is thought to play a role in development of ascites in ovarian cancer. Also, transdiaphragmatic spread to the pleura is common.
Prognosis in ovarian cancer is influenced by several factors, but multivariate analyses suggest that the most important favorable factors include:[17,18,19,20,21]
- Younger age.
- Good performance status.
- Cell type other than mucinous and clear cell.
- Lower stage.
- Well-differentiated tumor.
- Smaller disease volume prior to any surgical debulking.
- Absence of ascites.
- Smaller residual tumor following primary cytoreductive surgery.
For patients with stage I disease, the most important prognostic factor is grade, followed by dense adherence and large-volume ascites. DNA flow cytometric analysis of stage I and stage IIA patients may identify a group of high-risk patients. Patients with clear cell histology appear to have a worse prognosis. Patients with a significant component of transitional cell carcinoma appear to have a better prognosis.
Although the ovarian cancer-associated antigen, CA 125, has no prognostic significance when measured at the time of diagnosis, it has a high correlation with survival when measured 1 month after the third course of chemotherapy for patients with stage III or stage IV disease. For patients whose elevated CA 125 normalizes with chemotherapy, more than one subsequent elevated CA 125 measurement is highly predictive of active disease, but this does not mandate immediate therapy.[27,28]