Colon Cancer Mutation: Prognosis/Prediction–Response

To address the question that Zaanan and colleagues have asked, we have generated Kaplan–Meier (K-M) curves for the time-to-recurrence (TTR) end point to determine the magnitude of benefit from oxaliplatin treatment by mismatch repair (MMR) status in patients from National Surgical Adjuvant Breast and Bowel Project C-07 (Fig. 1) and to determine the effect size of MMR in oxaliplatin-treated patients (FLOX or mFOLFOX6) from C-07 or C-08 (Fig. 2). The plots suggest that only patients with MMR proficient (MMRp) may receive benefit from the addition of oxaliplatin to 5-fluorouracil (5-FU) + leucovorin; however, the oxaliplatin (oxali)–MMR interaction is not significant (P = 0.62; Fig. 1) and the analysis is severely underpowered to make a definitive conclusion due to the low number of patients and recurrences with MMR deficient (MMRd). In patients treated with oxaliplatin (FLOX or mFOLFOX6), 3-year TTR is 78.0% and 87.6%, respectively, for patients with MMRp and MMRd (P = 0.03; Fig. 2).See the original Letter to the Editor, p. 1300No potential conflicts of interest were disclosed.