The Impact of Mismatch Repair Status in Colorectal Cancer on the Decision to Treat With Adjuvant Chemotherapy: An Australian Population-Based Multicenter Study

Abstract

? AlphaMed Press 2016.Background. Testing for mismatch repair (MMR) status in colorectal cancer (CRC) may provide useful prognostic and predictive information. We evaluated the impact of such testing on real world practice regarding adjuvant chemotherapy for patients with resected CRC. Patients and Methods. A total of 175 patients with stage II and III mismatch repair-deficient (MMRD) CRC were identified from an Australian population-based study of incident CRCs. Their treatment decisions were compared with those for a cohort of 773 stage-matched patients with mismatch repair-proficient (MMRP) CRCs. The effect of MMR status, age, and pathologic characteristics on treatment decisions was determined using multiple regression analysis. Results. Overall, 32% of patients in stage II and 71% of patients in stage III received adjuvant chemotherapy. Among the stage II patients, those with MMRD cancer were less likely to receive chemotherapy than were MMRP cases (15%vs.38%;p