Prevalence of metastasis and survival of 788 patients with T1 rectal carcinoid tumors

Abstract

Prevalence of rectal carcinoids is increasing, partly because of increased colorectal cancer screening. Local excision (endoscopic or transanal excision) is usually performed for small (<1-2 cm) rectal carcinoids, but data on clinical outcomes from large population-based U.S. studies are lacking. The aims of this study were to determine the prevalence of metastasis of resected small rectal carcinoid tumors using a large national cancer database and to evaluate the long-term survival of patients after local resection as compared with radical surgery. The Surveillance Epidemiology and End Results database was used to identify 788 patients with rectal T1 carcinoids<2 cm in size. Prevalence of metastases at initial diagnosis and risk factors for metastases were analyzed. Cancer-specific survival (CSS) was calculated. A total of 727 patients (92.3%) had tumors≤10mm in diameter and 61 (7.7%) had tumors 11 to 19mm. Overall, 12 patients (1.5%) had metastasis at the time of diagnosis with prevalence of 1.1% in lesions≤10mm and 6.6% in lesions 11 to 19mm (P= .01). Survival of patients with T1 rectal carcinoids without metastasis was significantly better than those with metastasis (5-year CSS of 100% vs 78%, P< .001). Of 559 patients with T1N0M0 rectal carcinoids≤10mm, 5-year CSS was 100% in both groups who underwent local excision and those who underwent radical surgery. Larger T1 rectal carcinoid tumors (11-19mm) have significantly higher risk of lymph node metastases compared with those≤10mm. Survival is worse with metastatic disease. Local therapy is adequate for T1N0M0 rectal carcinoids≤10mm in size with excellent long-term outcomes.