Pathologic Analysis
TRG, tumor, Cancer
TUMOR, DEGENERATION, RESIDUAL TUMOR, REGRESSION, CANCER
Evaluations of residual tumor (R) were classified as follows: R0 resection (no microscopic and macroscopic residual tumor), R1 resection (only microscopic residual tumor), and R2 resection (macroscopic residual tumor). A condition without grossly and microscopically viable tumor in the entire surgical specimen, including the primary site and any resected lymph nodes, was defined as a pathologic complete response (pCR).The American Joint Committee on Cancer (AJCC)/College of American Pathologists (CAP) tumor regression grade (TRG) was classified as follows: TRG 0 (pCR: no residual tumor cells), TRG 1 (near complete response: single or small groups of residual tumor cells), TRG 2 (partial response: residual tumors with degeneration of tumor cells and desmoplastic response), TRG 3 (poor or no response: a large number of tumor cells observed with little or no response to treatment).