Impact of tumor location on lymph node metastasis in T1 colorectal cancer

Data evaluating the risk of lymph node metastasis depending upon the location of the primary tumor are limited in patients with T1 colorectal cancer. We aimed to evaluate the impact of tumor location on lymph node metastasis in T1 colorectal cancer. Patients who underwent an oncologic resection with curative intent for T1 adenocarcinoma of the colon and rectum between January 1997 and October 2014 were assessed. Exclusion criteria were distant organ metastases, previous or concurrent cancer, past history of surgical or medical cancer treatment, preoperative chemoradiation, and patients with inflammatory bowel disease or polyposis syndromes. Out of 232 (56 % male) patients fulfilling the study criteria, 24 (10 %) had lymph node metastasis. Age (65 vs 61 years, p = 0.1), gender (55 vs 63 % male, p = 0.5), tumor size (2 vs 2 cm, p = 0.49), and lymphovascular invasion (5 vs 8 %, p = 0.46) were not associated with lymph node metastasis. While there was no statistical significance (p = 0.2), lymph node positivity was higher in rectal cancer (14 %, n = 11/79) compared to colon cancer (9 %, n = 13/153). Although it was not statistically significant, lymph node positivity varies based on tumor location of T1 colorectal adenocarcinoma regardless of fundamental tumor characteristics including size, differentiation, and lymphovascular invasion.