Right-Sided and Left-Sided Colon Cancers are Two Distinct Disease Entities: an Analysis of 200 Cases in Pakistan.

Background: There is growing evidence that there are differences in histological and genetic characteristics along with clinical behavior between right- and left-sided colon carcinomas. We have compared various parameters of the two types and assessed associations of the results with prognosis in patients in Pakistan.

Materials And Methods: We reviewed 200 cases from our institutional database; 100 cases of right-sided and 100 cases of left-sided colon cancer. Parameters including age, gender, TNM stage, histological features and clinical outcome were analyzed.

Results: The patients with right-sided colon cancer were significantly older as compared to their counterparts with left-sided cancer. They presented with a lumbar mass rather than symptoms of obstruction and perforation as seen in left-sided colon cancers, and the histology showed higher percentage of poorly differentiated tumors with advanced pT stage. Moreover, Crohn's-like reactions, intra tumoral lymphocyte responses and other poor prognostic factors like lymph vascular invasion and perineural invasion were more common in right-sided cancers.

Conclusions: We found that right- and left-sided colon cancers are different from each other in terms of clinical presentation, histology and clinical behavior. Right-sided colon cancers are more aggressive and are associated with poorer clinical outcome as compared to left sided colon cancers in our population.