Abstract 54P
Background
Rectal neuroendocrine tumors (rNETs) represent approximately 20% of gastrointestinal neuroendocrine tumors, with a rising incidence over recent decades. However, data from Latin America remain limited.
Methods
This retrospective study included patients diagnosed with rNETs at the Instituto Nacional de Enfermedades Neoplásicas (INEN) between September 2009 and February 2024. Clinicopathological characteristics were analyzed, and overall survival (OS) was estimated using the Kaplan-Meier method. Survival differences were assessed with the log-rank test.
Results
57 patients were included, with a median age of 54 years (27–74); 66.7% were female. Advanced disease was observed in 40.4% (n=23), 59.6% (n=34) had localized disease. All tumors were well-differentiated, with 56.1% (n=32) classified as G1 and 43.9% (n=25) as G2. Among advanced cases, 87% (n=20) were G2, whereas 85.3% (n=29) of localized tumors were G1. Nodal involvement (N+) was present in 78.3% (n=18) of advanced cases, while 90.6% (n=29) of localized tumors had no nodal involvement (N-). Surgical resection of the primary tumor was performed in 21.1% (n=12), while endoscopic resection in 50.9% (n=29). Median tumor size was 1.1 cm (0.2–7.8 cm). Tumors >2 cm were observed in 78.3% (18/23) of advanced cases but were absent in localized disease. Median OS for all patients was 112.3 months (95% CI: 48.8–175.8), with a median follow-up of 25.4 months. Median OS in advanced disease was 48.4 months (95% CI: 29.6–66.9; p=0.001), while it was not reached for localized disease. G2 tumors had a median OS of 46.4 months, compared to an unreached median OS in G1 tumors (p < 0.001).
Conclusions
Tumor size >2 cm, G2 tumors, and N+ were strongly associated with advanced disease and worse survival outcomes. Early detection and resection of localized rNETs significantly improved survival, emphasizing the need for timely diagnosis and personalized treatment strategies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.