Subgroup Analyses
tumor, tumors
TUMOR, RECURRENCE, MUTANT, REGRESSION, RESIDUAL DISEASE, TUMORS
There was limited statistical power to investigate heterogeneity between subgroups in the effect of NAC on 2-year recurrence (Data Supplement). The more highly powered comparison of tumor regression rates within subgroups (Data Supplement) showed similar efficacy of NAC in different radiologic T and N stages, left- and right-sided tumors, age groups, sexes, with OxCap and OxFU, with shorter or longer proposed treatment duration, whether RAS-wt or mutant, and whether or not randomly assigned for panitumumab. The only strong association seen was with mismatch repair (MMR) status: moderate or greater regression after NAC was seen in just 7% (8/115) of MMR-deficient (dMMR) compared with 23% (128/553) of MMR-proficient (pMMR) tumors ((A) Regresssion grade by MMR status in preoperative chemotherapy group and (B and C) recurrence or residual disease by treatment allocation for patients with pMMR or unknown MMR status