Background : The search for high-risk factors in stage II colon cancer (CC) is ongoing and several highrisk factors for stage II CC have been identified; however, the effects of tumor sidedness on prognosis is not clear. This study aims to determine whether tumor sidedness could be identified as another high-risk factor for stage II CC.Methods : We retrospectively analyzed 189 patients with stage II CC, following consecutive curative resection surgery performed between 2008 and 2014. We compared clinicopathological findings and long-term outcomes between the patients with right colonic cancer (RCC) and patients with left colonic cancer (LCC). Prognostic factors for survival were determined using univariate and Cox proportional regression analyses.Results : A total of 72 patients were diagnosed with RCC and 117 patients were diagnosed with LCC.Patients with RCC were significantly older (p < 0.001) than those with LCC, and the number of harvested lymph nodes (HLNs) was greater in the RCC group (RCC: 25 vs. LCC: 19; p = 0.003). The overall survival (OS) was notably worse in the RCC group than the OS in the LCC group (5 year survival rate-RCC: 81.3% vs. LCC: 90.4%; p = 0.025), whereas no significant difference was observed in disease-free survival (5 year survival rate-RCC: 74.8% vs. LCC: 83.4%; p = 0.065). Cox proportional regression analysis showed that tumor sidedness (hazard ratio (HR): 3.78, 95% confidence interval (CI): 1.61-8.85, p = 0.022), gender (HR: 3.27, 95% CI: 1.27-8.47, p = 0.014), and the number of HLNs (HR: 4.58, 95% CI: 1.95-10.74, p < 0.001) were independent prognostic factors for OS.Conclusion : Patients with a right-sided primary tumor location have more negative prognostic factors and worse long-term outcomes than those with a left-sided primary tumor location in stage II CC.
BackgroundColorectal cancer (CRC) is a major health problem worldwide. CRC is the third most common cancer in the world and the second highest cause of cancer-related death [1,2]. Recently, several molecular and genetic mechanisms of CRC carcinogenesis have been identified [3,4]. It has also been reported that the oncological features differ between colon cancer (CC) and rectal cancer [5]. In stage II CC, Recurrence pattern and post-recurrence therapy between the groups Recurrence patterns and treatments for recurrence are summarized in Table 2. Ten patients (13.9%) recurred in the RCC group, compared with 14 patients (12.0%) in the LCC group. The recurrence sites were the liver, lungs, peritoneum, and bone. The liver was the most commonly recurring organ in both groups. There was no significant difference between the two groups in recurrence sites (p = 0.44).Treatments for recurrence were performed in 90% and 92.9% of cases in the RCC and LCC groups,