[A COMPARATIVE STUDY OF THE PATHOLOGICAL CHARACTERISTICS OF RIGHT SIDED VERSUS LEFT SIDED COLON CANCER]

This study aimed to investigate the pathologic differences between right and left sided colonic cancer.

The incidence of right sided colon cancer during the past several decades is increasing as compared to left sided colon cancer. There are cumulative publications describing epidemiological, pathological and genetic differences between right and left sided colon cancer. A few studies have also shown a lower survival rate in patients with right sided colon cancer as compared to patients with left sided colon cancer.

A retrospective study based on the accumulated data on right and left sided colonic cancer.

Data on 823 patients was collected; 426 patients (52.8%) had colon cancer located on the right side and in 397 patients (48.2%) it was located on the left side. There were no statistically significant differences between right and left colon cancer regarding sex, lymph node metastases and lymphovascular invasion. However, there was a significantly higher proportion of poorly differentiated adenocarcinomas (19%vs.8.7%; p<.001) and a trend to higher T stage (T3-4:87.7%vs.82.8%; p<.049) in right sided tumors as compared to left sided tumors. The incidence of mucinous tumors and mucinous components was also significantly higher in right sided tumors (7.3%vs.2%; p<.001, 13.1%vs.7%; p<.001).

We found histopathological differences between right and left sided colon cancer. Tumors on the right colon were found to be more aggressive, as expressed by poorer differentiation, higher T stage and mucinous tumors. The reasons are unclear, either the existence of two distinct molecular pathways or simply a delay in the diagnosis of right sided colon cancer. Future studies are needed to better understand the true nature of these differences.