The View of Turkish Oncologists Regarding MSI Status and Tumor Localization in Stage II and III Colon Cancer

Although several clinical factors which show the benefit of adjuvant chemotherapy (AC) in early-stage colon cancer use for evaluating the risk of relapse, there is no consensus on which risk factors are more reliable. In this study, we evaluated both the utility of MSI and the daily practice of the Turkish oncologists in stage II and III colon cancer.

We conducted an online questionnaire which was consisting of twenty questions including the treatment choices and duration about stage II-III colon cancer depending on sidedness and risk factors for relapse.

More than 65% of the oncologists declared the use of MSI testing in stage II colon cancer without considering any risk factors. In stage 3 colon cancer oncologists had an equal decision "to do or not to do" in MSI testing. More than 50% of the oncologists had preferred XELOX protocol in high-risk stage II (T4N0) colon cancer, while three out of four preferred observation in low-risk stage II (T3N0) patients without risk factors. Two-thirds of the oncologists had preferred 6 months of treatment in stage II colon cancer with at least one risk factor.

Turkish oncologists participating to this trial had declared conflicting results about adjuvant treatment in early-stage colorectal cancer in their daily practice compared with the updated guidelines, especially, MSI evaluation utility in stage III colon cancers, adjuvant chemotherapy (AC) duration, and oxaliplatin adding to AC in elderly and stage II patients.