Possible better long-term survival in left versus right-sided colon cancer - a systematic review.

INTRODUCTION Colon cancer is one of the most frequent types of cancer in Denmark and the western world. Recent studies indicate that there are differences between right- and left-sided colon cancer with regard to epidemiology, clinical manifestation, pathology and prognosis. The present systematic literature review focuses on this subject.

METHOD PubMed, the Ovid Database and the Cochrane Library of Systematic Reviews were searched for relevant literature in October 2011. Only 17 studies fulfilled the inclusion criteria, which were 1) literature published after 1998, 2) written in Danish or English, and 3) peer-reviewed publication.

RESULTS We found that patients with right-sided colon cancer were older, more often females, possibly had more co-morbidities, had more advanced tumour stages, increased tumour sizes, more poorly differentiated tumours, different molecular biological tumour patterns and a poorer prognosis than patients with left-sided colon cancer. Multivariate analyses showed that age, gender, mode of presentation (emergency/elective), co-morbidity and stage had significant influence on survival, but it was uncertain whether tumour location itself had such an effect, though the different molecular biological patterns indicate this.

CONCLUSION The findings potentially have consequences for the planning of screening and treatment of colon cancer, but further research in the area is needed.