- Pathologic documentation of adenocarcinoma of the colon with or without penetration of the serosa with no lymph node metastases (Stage II pT3N0 or pT4bNO lesions, excluding pT4aN0; Modified Astler-Coller Stage B2); there can be no distant metastases or penetration of adjacent organs or structures; proximal, distal, and radial margins must be free of tumor Important note: A tumor nodule > 3 mm in diameter in the perirectal or pericolonic adipose tissue without histologic evidence of residual node in the nodule is classified as regional/pericolonic node metastasis; however, a tumor nodule =< 3 mm in diameter is classified in the T category as discontinuous extension (i.e., pT3); multiple metastatic foci seen microscopically only in the pericolonic fat should be considered as metastasis in a single lymph node for classification; although six or more nodes evaluated from the specimen is optimal, a minimum of three nodes (periodic or mesenteric) for evaluation is required for inclusion in the study