Tumor location impact in stage II and III colon cancer: epidemiological and outcome evaluation

Colon cancer (CC) is a public health problem worldwide and in Tunisia. The incidence is estimated to be 1.2 million per year, and more than 600,000 deaths every year (1). In the recent years, with knowledge advancement in genetic and molecular mechanism of carcinogenesis, CC is no longer considered as a unique disease. Distinguishing CC based on anatomical location was first described by Bufill et al. in 1990 (2). Subsequent publications pointed out several differences between right-sided (RCC) and left-sided CC (LCC) regarding epidemiology, pathogenesis, embryologic, genetic-epigenetic alterations, molecular pathways and outcome (2-4). Roughly, it is suggested that anatomical site could have, in the future, an impact in the management of CC. However, data regarding prognosis remain controversial and a great debate is open whether tumor location itself plays a prognostic role. A poorer survival of RCC was reported by most studies (5,6). These observations are more evident in advanced stage with differences in response to targeted therapies (7,8). In a large population based study of 57,847 patients from the surveillance, epidemiology and end results (SEER) database, disease specific survival was significantly worse in RCC patients vs. LCC patients, with a hazard ration of 0.77 (0.72±0.81) in stage IV (4). However, in early stage data are less defined and prognostic role is still under investigation. Patterns of such anatomical distribution in various population would help a better understanding of this issue. We aimed in our current study to describe clinico-pathological characteristics and differences between RCC and LCC in Tunisian population. We also analyzed outcome to determine whether location is of prognostic significance