RESUMO
BACKGROUND: The frequency of colorectal cancer (CRC) with defective mismatch repair (dMMR) is estimated between 5 and 15%. In our population, the frequency of dMMR is unknown. Our objective was to show the frequency of dMMR. METHODS: Determination of dMMR with immunohistochemistry was performed prospectively for 202 patients who presented consecutively with CRC for the first time at our institution. RESULTS: The median age was 59 years (IQR 47 to 68), 119 (58.9%) were women, and 43 (21.3%) cases showed dMMR. The only clinicopathological characteristics associated with dMMR were the location in the right colon and the presence of a family history of cancer. In the multivariate analysis, only the presence of the tumor in the right colon was associated with dMMR (OR = 5.823, 95%-C.I. = 2.653-12.784, p < .001). CONCLUSION: The 21.3% of the cases demonstrated a dMMR and the only clinical-pathological characteristic associated with dMMR was location in the right colon.