Staging of Ovarian Cancer

Ovarian malignancies are staged according to the International Federation of Gynecology and Obstetrics (FIGO) system. The FIGO staging system of 1987 (Table 118-4) is based on the findings at surgical exploration. A preoperative evaluation should exclude the presence of extraperitoneal metastases. A thorough surgical exploration is important because subsequent treatment will be determined by the stage of disease. In patients whose exploratory laparotomy does not reveal any macroscopic evidence of disease by inspection and palpation of the entire intraabdominal space, a careful search for microscopic spread must be undertaken. In an earlier series in which patients did not undergo careful surgical staging, the overall 5-year survival for patients with apparent stage I epithelial ovarian cancer was only about 60%. Survival rates of 90% to 100% have been reported for properly staged patients found to have stage IA or IB disease.

Metastases in apparent stage I or II epithelial ovarian cancer are common. About 30% of patients whose ovarian epithelial cancers appear to be confined to the pelvis have occult metastatic disease in the upper abdomen or in the retroperitoneal lymph nodes. The importance of a comprehensive initial surgical staging is emphasized by the findings of a cooperative national study in which 100 patients with apparent stage I or II disease who were referred for subsequent therapy underwent additional surgical staging. In this series, 28% of patients initially thought to have stage I disease were upstaged, and 43% of patients thought to have stage II disease had more advanced disease. Thus, 31% of patients were upstaged as a result of additional surgery, and 77% were reclassified as stage III. Histologic grade was a significant predictor of occult metastasis, that is, 16% of patients with grade 1 lesions were upstaged, compared to 34% with grade 2 and to 46% with grade 3 disease.

Although the literature has emphasized the importance of thorough surgical exploration in patients with disease apparently localized to the ovaries, scant recognition is made of the semantic difficulty presented by the concept of extension to other pelvic (ie, stage II) or abdominal (ie, stage III) organs. No problem exists when the surgeon encounters discrete implants, or seeds, separate from the primary tumor, or when solid tumor is found growing into adjacent structures. A more common situation, however, is the apparently benign adherence of the tumor to adjacent structures in the absence of metastatic implants or obvious direct tumor extension. There is a considerable body of evidence that such benign adherence, when it is dense, is associated with a relapse risk equivalent to stage II, and that these patients should not be included in stage I, but rather in stage II. Adherence is considered dense when sharp dissection is required to mobilize the tumor, when a raw area is left at the site of adherence, or when cyst rupture results from dissecting free the adhesions. It is the practice at most North American centers to advance the stage of densely adherent tumors to stage II, and this was done in a recent multicenter study of stage I and II disease.