Ovarian epithelial tumors spread primarily by direct exfoliation of cells throughout the peritoneal cavity, but they also spread via the lymphatic and hematogenous routes. Germ cell tumors have a greater predilection for spread via the retroperitoneal lymphatics, which must be evaluated carefully when staging those tumors that appear to be confined to the ovary.

The most common and earliest mode of dissemination of epithelial tumors is by the exfoliation of cells along the peritoneal surfaces. The cells spread directly to the pelvic and abdominal peritoneal surfaces, and tend to follow the path of circulation of peritoneal fluid from the right pericolic gutter cephalad to the right hemidiaphragm. The intestinal mesenteries become involved by peritoneal metastases. Adhesions form between loops of intestine producing mechanical obstruction, even though involvement of the lumen of the intestine by direct extension is uncommon. The intestinal dysfunction can also result from involvement by tumor of the myenteric plexus, the autonomic innervation of the intestine that is found in the mesentery. This condition has been referred to as carcinomatous ileus.

Spread via the lymphatics is common in epithelial ovarian cancer. Apparent stage I and II tumors have retroperitoneal lymphatic dissemination in about 5% to 10% in most series, whereas lymphatic dissemination in stage III has been reported to be as high as 42% to 78% in carefully explored patients. Most of these lymph nodes are not enlarged, but are microscopically positive for malignant cells. Spread through the retroperitoneal and diaphragmatic lymphatics can result in metastasis to the supraclavicular lymph nodes.

Blood-borne metastasis of ovarian cancer is uncommon at diagnosis and is often a late finding in the disease. Hematogenous dissemination at the time of diagnosis to the parenchyma of the liver or lung is seen in only 2% to 3% of patients. Indeed, most patients who have disease dissemination cephalad to the diaphragm at the time of presentation have a right pleural effusion. Metastasis to the central nervous system is rare and spread to the bone is very rare, except for the clear cell histologic type. However, in patients who survive many months and years with their disease, involvement of distant sites is more common. In one report by Dauplat and colleagues, distant metastases consistent with stage IV findings were documented in almost two fifths of patients who died of ovarian cancer originally thought confined to the peritoneal cavity.