Purpose: Cancer of the colon and rectum has been classically viewed as the same disease entity. However, there are some differences both in the clinical features and gross macroscopic pathology between right and left sided colonic malignancies. Furthermore, recent research has added much controversy on the issue by demonstrating quite a few differences, mostly in the field of molecular biology. Since tumor pathology and staging is the major determinant of the disease outcome, comparison of these parameters between right and left colon cancer is reasonably expected to contribute to a better understanding of the nature of the adenocarcinoma of the colon.
Patients and methods: A retrospective review of the charts of patients with colorectal cancer operated on at the Cleveland Clinic Florida from March 1996 to April 2000 was conducted. Patients were divided into two groups according to the location of the tumor (right or left colon) and pathology between the two groups was compared.
Results: One hundred and eighty-four patients were included in the study. Sixty individuals had right colon cancer, while 124 subjects had left colon lesions. Dukes' A (stage I) colon cancer had statistically significant higher incidence in left colon lesions (p=0.0084). Conversely, Dukes' C(stage III) tumors presented more often in the right colon (p=0.029). Grade III lesions showed a clear superiority for the right colon (p=0.0014), while grade II lesions were more commonly found in the left colon (p=0.0201). Grade III lesions were more common in the right colon (p=0.0200) when early colonic cancers (stage 0,I and II pooled together) were compared.
Conclusion: A shift in severity towards the right colon has been documented both in terms of stage and grade. These results should be viewed in the light of recent research data suggesting a different molecular biology pattern between right and left colonic tumors. The clinical implications of these differences, if any, and their impact on the patient management remain to be determined.