Characteristics and Survival of Patients With Colonic Compared to Rectal Neuroendocrine Tumors: A SEER Registry Analysis

INTRODUCTION: Colon and rectal neuroendocrine tumors (NETs) have varying disease behaviors, presentations, and outcomes. Rectal NETs are detected early; colonic NETs present later and more aggressively. We compared demographic, tumor, treatment, and survival characteristics of colonic versus rectal NETs. METHODS: This retrospective cohort study used SEER data (2000-2022) to identify adults with colonic or rectal NETs. Demographic, tumor, and treatment characteristics were compared by tumor site. Five-year overall survival (OS) and cancer-specific survival (CSS) were analyzed using Kaplan-Meier statistics and multivariable Cox proportional hazards regression. Additional site-specific analyses evaluated stage and treatment patterns by race, ethnicity, and household income. RESULTS: Twenty-four percent of 30 246 patients had colonic NETs, and 76.0% had rectal NETs. Rectal NET patients were younger (55.7 vs. 62.9 years, p < 0.001) and more often Black, Asian, or Hispanic. Colonic NETs were more frequently poorly differentiated (43.9% vs. 7.0%), larger (median 30 vs. 5 mm), and more likely to have liver metastases (27.7% vs. 3.7%). Rectal NETs underwent local excision (92.1%), colonic NETs required colectomy (72.3%). Rectal NETs demonstrated higher 5-year OS (88.8% vs. 55.8%) and CSS (93.8% vs. 58.2%, p < 0.001). Stage III colonic NETs had higher CSS than rectal NETs (67.3% vs. 53.5%, p < 0.001). CONCLUSION: Colonic and rectal NETs have distinct clinicopathologic profiles, treatment patterns, and stage-specific outcomes. These findings support site-specific evaluation while emphasizing the importance of stage and tumor biology in prognosis.