Increasing Detection of Early-Onset Rectal Neuroendocrine Neoplasms in the Era of Earlier Colorectal Cancer Screening

Background This study aimed to evaluate contemporary national trends in the presentation, management, and outcomes of early-onset rectal neuroendocrine neoplasms (EORNETs). Methods A retrospective cohort analysis of patients <50 years who underwent surgery for rectal neuroendocrine neoplasms was performed using the National Cancer Database (NCDB) (2004-2023). Patients undergoing surgery were categorized as local tumor excision or radical resection. Five-year overall survival (OS) was estimated using Kaplan-Meier analysis, and multivariable Cox proportional hazards analysis was used to identify factors associated with OS. A sensitivity analysis was also performed in the well-differentiated neuroendocrine tumor subgroup. Results 7285 patients were included; 6638 (91.1%) underwent local excision and 647 (8.9%) radical resection. The annual number of surgically treated cases increased from 234 in 2004 to 778 in 2023. 83.0% of tumors with known grade were low grade, and 90.6% of tumors with known clinical stage were stage I. Radical resection was associated with larger tumors, higher grade, more advanced stage, lymphovascular invasion, and liver metastases (all P < .001). Five-year OS was higher after local excision than radical resection (97.5% vs 85.7%, P < .001). In the full multivariable model, radical resection was associated with worse OS (HR 3.43, 95% CI 1.60-7.36; P = .002); however, this association was no longer statistically significant in the well-differentiated tumor subgroup (HR 2.52, 95% CI 0.97-6.54; P = .057). Conclusions The number of surgically treated EORNET cases substantially increased over time. Local excision was the predominant treatment. These findings are compatible with increased detection of indolent lesions through greater endoscopic evaluation.