Inverse Association of Age with Risk of Lymph Node Metastasis in Superficial Colorectal Cancer: A Large Population-Based Study.

ABSTRACT

BACKGROUND: Superficial colorectal cancer (SCRC) is defined as colorectal cancer (CRC) confined to the mucosa or submucosa. Endoscopic resection (ER) is widely used to resect differentiated SCRC from patients without lymph node metastasis (LNM). However, it is unclear whether ER is suitable for use with patients with differentiated early-onset SCRC because early-onset CRC is more aggressive. Therefore, we aimed to investigate the association between age of CRC onset and LNM. MATERIALS AND METHODS: We retrieved data for patients with surgically resected differentiated-type SCRCs from the Surveillance, Epidemiology, and End Results (SEER) database. Rate of LNM was compared among patients aged 18-39, 40-49, 50-59, 60-69, and ≥70 years. The association between age and LNM was further examined using multivariate logistic regression. RESULTS: We retrieved 34,506 records of differentiated SCRCs from the SEER database, including 667 patients aged 18-39 years, 2,385 aged 40-49, 8,075 aged 50-59 years, 9,577 aged 60-69 years, and 13,802 aged ≥70 years. Rates of LNM were 15.74%, 14.13%, 10.67%, 8.07%, and 6.76% for patients aged 18-39, 40-49, 50-59, 60-69, and ≥70 years, respectively. We found an inverse correlation between age at diagnosis and risk of LNM from the univariate analysis (p < .001). Compared with patients aged 18-39, the odds ratios with 95% confidence interval (CI) for patients aged 40-49, 50-59, 60-69, and ≥70 years were 0.90 (0.71-1.15, p = .376), 0.69 (0.56-0.87, p = .001), 0.54 (0.43-0.68, p < .001), and 0.47 (0.38-0.60, p < .001), respectively. CONCLUSION: In differentiated SCRCs, younger age at diagnosis was associated with higher risk of LNM. IMPLICATIONS FOR PRACTICE Endoscopic resection (ER) is widely used to resect differentiated superficial colorectal cancer (SCRC) without lymph node metastasis (LNM). However, no study has ever investigated risk of LNM of early-onset SCRC compared with average onset SCRC to explore whether ER is suitable for early-onset SCRC. To the authors' knowledge, this population-based study is the first study to find inverse correlation between age at diagnosis and risk of LNM in differentiated SCRCs. This finding indicates that ER may not be suitable for young patients with differentiated SCRC. Because the 30-day operative mortality after surgery is higher but the risk of LNM is lower in older patients compared with younger patients, ER for differentiated SCRCs may be advantageous over surgery for older patients.