Clinical Characteristics and Outcomes of Young Adult Patients with Small Intestinal Neuroendocrine Tumors Differ from Those of Older Adults

Abstract

INTRODUCTION: Small intestinal neuroendocrine tumors (siNETs) are most commonly diagnosed in the sixth and seventh decades of life. Little is known about the characteristics and outcomes of patients diagnosed at younger ages. METHODS: The National Cancer Database was queried for patients diagnosed with siNETs from 2004 to 2018. Young adults (18 to 39 years) and older adults (40+ years) were compared using Wilcoxon and Chi-square tests and Kaplan-Meier estimates. RESULTS: A total of 26,902 adults with siNETs were identified. Median age was 62 years (interquartile range [IQR] 53 to 71). Young adults (1,130; 4.2%) were more likely to be of non-white race (21.2% vs 15.0%, p < 0.001) and Hispanic ethnicity (8.4% vs 4.5%, p < 0.001). Of young adults, 51.9% had stage 3 disease and 24.7% had stage 4 disease, compared with 54.4% and 29.2%, respectively, of older adults (p < 0.001); 91.5% of young adults and 91.6% of older adults underwent resection (p = 0.89). Young adults were more likely to have negative margins (90.6% vs 84.7%, p < 0.001) and more regional nodes examined (median 11.0 (IQR 1.0 to 20.0) vs 9.0 (IQR 1.0 to 16.0), p < 0.001). Ninety-day mortality was 0.9% for young adults and 3.5% for older adults (p < 0.001). Across all stages, young adults had more favorable 5-year survival (Table). Table. - Clinical Characteristics and Survival Rates of Young vs Older Adults with siNETs Variable Young adults (n = 1,130) Older adults (n = 25,772) p Value Grade 1 76.9% 79.9% 0.046 Grade 2 20.7% 18.1% Grade 3 2.4% 2.0% Stage 1-2 23.4% 16.4% <0.001 Stage 3 51.9% 54.4% Stage 4 24.7% 29.2% 5-year survival: stage 1–2 93.2% (95% CI 88.0–98.5) 80.3% (95% CI 78.6–82.0) <0.001 5-year survival: stage 3 97.0% (95% CI 94.7–99.1) 86.6% (95% CI 85.8–87.5) 5-year survival: stage 4 84.1% (95% CI 78.3–90.3) 71.3% (95% CI 69.8–72.9) CONCLUSION: Young adults with siNETs are demographically different from older patients, with a higher percentage of non-white and Hispanic patients. Young adults present with less advanced disease and are more likely to undergo resection with negative margins and have more regional nodes examined. Young adults have more favorable short- and long-term survival regardless of stage, which warrants separate evaluation for prognostication.