Frequency of Defective Mismatch Repair System in a Series of Consecutive Cases of Colorectal Cancer in a National Cancer Center.

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.