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

Background and Aims: 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. Methods: 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. Results: A total of 727 patients (92.3%) had tumors ≤10 mm in diameter and 61 (7.7%) had tumors 11 to 19 mm. Overall, 12 patients (1.5%) had metastasis at the time of diagnosis with prevalence of 1.1% in lesions ≤10 mm and 6.6% in lesions 11 to 19 mm (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 ≤10 mm, 5-year CSS was 100% in both groups who underwent local excision and those who underwent radical surgery. Conclusions: Larger T1 rectal carcinoid tumors (11-19 mm) have significantly higher risk of lymph node metastases compared with those ≤10 mm. Survival is worse with metastatic disease. Local therapy is adequate for T1N0M0 rectal carcinoids ≤10 mm in size with excellent long-term outcomes.