Staging classification for cancer of the ovary, fallopian tube, and peritoneum

Ovarian cancer is the seventh most common cancer diagnosis among women worldwide, and the fifth most common cancer diagnosis among women in higher-resource regions 1. The world rate is estimated to be 6.3 per 100 000 women, and is highest in high-resource countries (9.3 per 100 000 women) 1. Primary peritoneal cancer and primary fallopian tube cancer are rare malignancies but share many similarities with ovarian cancer. Clinically, these 3 cancers are managed in a similar manner 2. The main purpose of staging systems is 2-fold: to provide standard terminology that allows comparison of patients between centers; and to assign patients and their tumors to prognostic groups requiring specific treatments. Ovarian cancer is staged surgically and pathologically, and the last revision of the FIGO staging classification was made in 1988 (Rio de Janeiro). The FIGO Committee on Gynecologic Oncology feels that it is time to revise this classification to improve utility and reproducibility. Cancer staging evolves continuously as scientific developments occur, diagnostic methods improve, and more accurate prognostic information becomes available. Over the past quarter of a century, several scientific developments have challenged traditional concepts in ovarian cancer. Initially, it was recognized that ovarian cancer is not a homogeneous disease, but rather a group of diseases—each with different morphology and biological behavior. Approximately 90% of ovarian cancers are carcinomas (malignant epithelial tumors) and, based on histopathology, immunohistochemistry, and molecular genetic analysis, at least 5 main types are currently distinguished: high-grade serous carcinoma (HGSC 70%); endometrioid carcinoma (EC 10%); clear-cell carcinoma (CCC 10%); mucinous carcinoma (MC 3%); and low-grade serous carcinoma (LGSC 10 mm in greatest dimension), even if there are no retrospective data supporting quantification of the size of metastasis in IIIA1. Involvement of retroperitoneal lymph nodes must be proven cytologically or histologically. Could some carcinomas that have extended beyond the pelvis with exclusively retroperitoneal lymph node involvement (stage IIIA1) represent independent LGSCs arising in retroperitoneal lymph nodes from endosalpingiosis? Serous borderline tumors and LGSCs may develop in retroperitoneal and cervical lymph nodes from endosalpingiosis, often in association with serous borderline tumors of the ovary and with favorable prognosis [33,34. In none of the reported case series was a histopathologic distinction made between HGSC and LGSC. Should the new stage IIIA1 be limited to involvement of the retroperitoneal lymph nodes below the diaphragm? It was suggested that upward nodal involvement (e.g. mediastinal nodes) should be included but, for now, the Committee felt that the stated limitation was appropriate. Is the 2-cm cutoff between IIIB and IIIC justified? Regarding the amount of peritoneal involvement, it was claimed that stage III tumors should be divided into microscopic and macroscopic, and if the latter measurement (in centimeters) should be given. Further distinction should be made between single small lesions within the omentum (< 2 cm) and diffuse peritoneal disease including the upper abdomen and diaphragm. Specific mention should be given to bowel infiltration (transmural with mucosal involvement) and umbilical deposit (currently IVB); however, some consider that involvement of the umbilicus should be IIIC rather than IV as it represents peritoneal extension into the urachal remnant. Similarly, isolated parenchymal liver metastasis and splenic parenchymal metastasis are susceptible to cytoreductive surgery and, according to some investigators, should be IIIC, although this was not adopted by the Committee (i.e. transmural bowel infiltration, umbilical deposit, and parenchymal metastases in the liver and spleen or elsewhere such as lung and bone are assigned to stage IVB). To classify IIIA1 cases histologically. To compare outcome of stage IIIA1(i) and IIIA1(ii) cases. To compare outcome of stage IIIA1 and IIIA2 cases. Stage IVA: Pleural effusion with positive cytology Stage IVB: Parenchymal metastases and metastases to extra-abdominal organs (including inguinal lymph nodes and lymph nodes outside of the abdominal cavity) Any T, any N, M1 Stage IV is defined as distant metastasis and includes patients with parenchymal liver/splenic metastases and extra-abdominal metastases; 12%–21% of patients present with stage IV disease 12. Extension of tumor from omentum to spleen or liver (stage IIIC) should be differentiated from isolated parenchymal metastases (stage IVB). Should macroscopic and positive lymph nodes above the renal vessels be considered stage III or IV? The primary site (i.e. ovary, fallopian tube, or peritoneum) should be designated where possible. In some cases, it might not be possible to delineate the primary site clearly; such cases should be listed as “undesignated.” The histologic type should be recorded. The staging includes a revision of stage III patients; assignment to stage IIIA1 is based on spread to the retroperitoneal lymph nodes without intraperitoneal dissemination because an analysis of these patients indicates that their survival is significantly better than that of patients with intraperitoneal dissemination. Involvement of retroperitoneal lymph nodes must be proven cytologically or histologically. Extension of tumor from omentum to spleen or liver (stage IIIC) should be differentiated from isolated parenchymal metastases (stage IVB). Splenectomy seems to take care of isolated metastases in a better way than partial hepatectomy. In future, isolated splenic metastasis may be considered stage IIIC rather than stage IV, whereas parenchymal liver metastasis would remain stage IVB. L.D. and N.B. have received honoraria for appearing on various speaker forums about HPV vaccination and have received research from and for The other Committee members have no of