Differences in risk factors, demographic and clinicopathologic characteristics at diagnosis between proximal and distal colon cancer: A multicenter retrospective cohort analysis

Introduction and aims

There are differences, with genetic and embryologic support, in the clinical behavior of proximal colon cancer (PCC) (right colon: cecum, ascending colon, and transverse colon) and distal colon cancer (DCC) (left colon: descending colon, sigmoid colon, rectum). Our aim was to determine whether there was a divergent pattern in the demographic characteristics, risk factors, TNM stage, and clinical stage at diagnosis between patients with PCC and those with DCC.

Material and methods

A retrospective, analytic, and multicenter study was conducted. Medical records of patients diagnosed with colorectal cancer, confirmed by histopathology and with TNM staging, within the time frame of 2018-2023, were collected from two hospital centers in the city of Chihuahua. They were divided into the PCC and DCC groups, for evaluating the abovementioned characteristics.

Results

From a total of 513 cases, 404 were included in the study. Significant differences were found in the demographic characteristics of female sex and a history of cholecystectomy, both with a greater relative frequency for PCC. Distant metastasis was present in 35.6% of patients, despite their younger age at diagnosis. The rectum was the most commonly affected segment in the DCC group, as was the ascending colon in the PCC group. There was a greater prevalence of peritoneal carcinomatosis in the PCC group. In contrast, the DCC group had a greater prevalence of distant metastasis to other organs, as both individual metastasis (M1a) and multiple site metastasis (M1b). There were no considerable differences in the KRAS, NRAS, or BRAF gene mutations between the two groups.

Conclusions

PCC was associated with a history of cholecystectomy and female sex and had more aggressive TNM staging, compared with DCC.