Pathologic factors are more important than tumor location in long-term survival in colon cancer

Proximal and distal colon cancers differ in terms of epidemiology, clinical presentation, and pathologic features. The aim of our study was to evaluate the impact of right-sided (RC), transverse (TC), and left-sided (LC) colon cancer on morbidity rates and oncological outcomes.

A retrospective analysis of patients with resected colon cancer between 2004 and 2014 was conducted. Cox proportional hazard models were used to assess predictors of overall (OS), and disease-specific survival (DSS), as well as disease-free survival (DFS).

A total of 1189 patients were included. RC patients (n = 618) were older, predominantly women, and had a higher comorbidity rate. LC (n = 454) was associated with symptomatic presentation and increased rates of laparoscopic surgery. Multivisceral resections were more frequently performed in TC tumors (n = 117). This group was admitted 1 day longer and had a higher complication rate (RC 35.6% vs. TC 43.6% vs. LC 31.1%, P0.032). Although the incidence of abscess/leak was similar between the groups, the necessity of readmission and subsequent reoperation for a leak was significantly higher in LC patients. Pathology revealed more poorly differentiated tumors and microsatellite instability in RC. Kaplan-Meier curves demonstrated worse 5-year OS for right-sided tumors (RC 73.0%; TC 76.2%. LC 80.8%, P0.023). However, after adjustment, no differences were found in OS, DSS, and DFS between tumor location. Only pathological features were independently correlated with prognosis, as were baseline characteristics for OS.

Tumor location in colon cancer was not associated with survival or disease recurrence. Pathological differences beyond tumor stage were significantly more important.