Clinical group

Extent of disease/surgical result

I

A Localized tumor, confined to site of origin, completely resected

B Localized tumor, infiltrating beyond site of origin, completely resected

II

A Localized tumor, gross total resection, but with microscopic residual disease

B Locally extensive tumor (spread to regional lymph nodes), completely resected

C Locally extensive tumor (spread to regional lymph nodes), gross total resection, but microscopic residual disease

III

A Localized or locally extensive tumor, gross residual disease after biopsy only

B Localized or locally extensive tumor, gross residual disease after major resection (≥50 percent debulking)

IV

Any size primary tumor, with or without regional lymph node involvement, with distant metastases, irrespective of surgical approach to primary tumor