Analysis of metastasis and survival after different treatment in patients with T1 stage colonic neuroendocrine tumors
Objective To explore the metastasis rate and related risk factors of T1 stage colonic neuroendocrine tumor(C-NET),and to compare the long-term survival outcomes of patients with non-metastatic(T1N0M0 stage)C-NET after local excision(LE)or radical surgery(RS).Methods Clinical information of 433 patients diagnosed with C-NET in the SEER database from January 1,2004 to December 31,2015 were analyzed.Cox regression was used to analyze the influencing factors of metastasis of C-NET.The patients without metastasis were divided into LE group and RS group,and assigned in a 1∶1 ratio using propensity score matching(PSM)according to gender,age,tumor largest diameter,and infiltration depth,with a caliper value set to 0.02.Kaplan-Meier survival curve was used to analyze 5-year cancer-specific survival(CSS)and overall survival(OS)of patients.Cox regression analysis was used to evaluate the influence of metastasis on survival.Results Among 419 C-NET patients,19(4.52%)had distant metastases.Cox regression analysis showed that 11-20 mm of tumor large diameter(HR=9.264,95%CI 3.322-25.835,P<0.001),right colon location(HR=0.116,95%CI 0.042-0.321,P<0.001),and submucosal invasion(HR=5.842,95%CI 1.858-18.371,P=0.003)were independent risk factors for distant metastasis of T1 stage C-NET.The 5-year OS rates of non-metastatic and metastatic patients were 94.5%and 47.4%,respectively(χ2=79.762,P<0.001),and their 5-year CSS rates were 99.5%and 55.7%,respectively(χ2=164.604,P<0.001).Before PSM,the 5-year OS rates of non-metastatic C-NET patients after LE and RS were 95.8%and 90.1%(χ2=2.679,P=0.063),and the 5-year CSS rates were 100.0%and 97.2%(χ2=0.579,P=0.038);after PSM,the 5-year OS rates of non-metastatic patients after LE and RS were 96.8%and 92.1%(χ2=3.606,P=0.058),and the 5-year CSS rates were 100.0%and 98.5%(χ2=1.015,P=0.314).After PSM,there was no significant difference in the 5-year OS and CSS of patients with defferent tumor location,tumor large diameter,or submucosal invasion between the LE and RS groups.Conclusions 11-20 mm of tumor diameter,right colon location,and submucosal invasion might be independent risk factors for distant metastasis of T1 stage C-NET,and LE could be an appropriate treatment option for non-metastatic C-NET.