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BACKGROUND: The risk of lymph node positivity in early-stage colon cancer is a parameter that impacts therapeutic recommendations. However, little is known about the effect of age on lymph node positivity in colon cancer with mucosal invasion. In this study, we aimed to quantify the effect of younger age on lymph node positivity in colon cancer with mucosal invasion. METHODS: All patients were identified between 2004 and 2014 in the Surveillance, Epidemiology, and End Results database. Patients were stage T1-T2, did not undergo preoperative radiotherapy, had at least one lymph node examined, and underwent a standard colon cancer operation. Demographics and pathological data were compared between different age ranges. A nomogram model was built to estimate the probability of nodal involvement according to different characteristics. Decision curve analysis was performed by calculating the net benefits for a range of threshold probabilities. RESULTS: This study identified 41,490 patients who met the eligibility criteria for our study. 1.4% (n = 620) of patients were under 40 years old; 5.9% (n = 2571) were between 40 and 49 years old. Within each T stage, positive lymph node rates decreased with increasing age. In univariate analyses, the positive lymph node rates for patients 20 to 39 years of age were significantly higher than in patients in the reference group for stages T1 and T2. After dividing the colon into the left and right parts, these trends remained. The lymph node metastatic rate was higher in the right colon than in the left colon in terms of different age ranges. The nomogram prediction system represents a novel model with which to estimate lymph node metastasis in early T stage colon adenocarcinomas based on four risk factors with a C-index of 0.657 (95% CI: 0.658-0666). CONCLUSIONS: Our study demonstrates that the risk of lymph node metastasis was higher in young (< 40 years) patients with early-stage colon adenocarcinomas. Therefore, more aggressive screening and therapeutic strategies should be considered for young patients with colon adenocarcinoma.
Xie et al. (Wed,) studied this question.