The prognostic implications of primary tumor location on recurrence in early-stage colorectal cancer with no associated risk factors

Sung Il Kang, Duck-Woo Kim, Yoonjin Kwak, Hye-Seung Lee, Min Hyun Kim, Myung Jo Kim, Heung-Kwon Oh, Sung-Bum Kang

Recently, several reports have suggested that tumor location serves as a prognostic biomarker in advanced colorectal cancer. However, the prognostic implication of tumor location in patients with early-stage colorectal cancer remains unclear. This study was aimed to examine the prognostic implication of tumor location in patients with early-stage colorectal cancer. Patients with stage I and low-risk stage II colorectal cancer, treated with radical surgery in a hospital setting between May 2003 and September 2014, were retrospectively reviewed. Patients who underwent (neo) adjuvant chemotherapy and/or radiotherapy and whose microsatellite instability (MSI) status was lacked were excluded. Distal colon cancer was defined as tumors located from the splenic flexure colon to the sigmoid colon. A total of 712 patients were included in this study. Of these patients, 23 (3.2%) had a recurrence at a median follow-up time of 46 months. The tumor recurrence rate was significantly low in patients with proximal colon cancer. In the multivariate analysis, tumors located in the distal colon or rectum (distal colon, hazard ratio [HR] 9.213, P = 0.035; rectum, HR 15.366, P = 0.009) and T3 tumors (HR 4.590, P = 0.017) were related to tumor recurrence. A higher prevalence of tumor recurrence was found in patients with two recurrence factors than those who had only one factor or none (P < 0.001). Tumor location, as well as T stage, had prognostic implication in patients with early-stage colorectal cancer. Validation of our results is needed in a large cohort with genetic characterization.