Prognostic effect of sidedness in early stage versus advanced colon cancer.

In this large, population-based study, right-sided presentation has a significant prognostic impact: in early stage, right-sidedness is favorably prognostic among stage II tumors and not prognostic in stage III disease. After relapse, right- sidedness is associated with an inferior prognosis, regardless of initial stage of presentation. Colon tumor sidedness is independently prognostic and may be considered in treatment assignment for both early stage and advanced disease.