Treatment trends of mucinous small bowel adenocarcinoma: An NCDB analysis.

Abstract

e16478 Background: Mucinous small bowel adenocarcinoma (MSBA) is an exceedingly rare histological subtype of small bowel adenocarcinoma. With adenocarcinomas accounting for less than 5% of all small bowel cancers, there are very few studies that specifically investigate the mucinous subtype. Generally, MSBA is thought to arise more often in younger Caucasian patients with a history of inflammatory bowel disease, such as Crohn’s or ulcerative colitis. While surgery is believed to be the primary treatment, given its rarity, no comprehensive studies in the current literature characterize its overall prognosis and treatment outcomes. Methods: The National Cancer Database (NCDB) was used to identify patients with MSBA from 2004-2019 using the histology code 8480, as assigned by the Commission on Cancer Accreditation program. Kaplan-Meier, ANOVA Chi-Square, and Multilevel Logistic Regression were performed, and statistical significance was set at α = 0.05. Data were analyzed using SPSS version 30. Results: 1776 patients with MSBA were identified. 1414 patients (79.62%) received surgery, with a longer overall survival (OS) time compared to non-surgical patients (81.61 months vs. 13.89 months, p < 0.001 ). The majority of patients received a lobectomy, with 734 patients (41.33%) surviving on average for 82.63 months. 264 patients (14.86%) underwent a hepatectomy, and 46 patients (2.59%) underwent an extended lobectomy. Surgery type did not significantly impact OS time. 645 patients (36.32%) received adjuvant chemotherapy, with a longer OS compared to patients with no adjuvant therapies (81.03 months vs. 59.47 months, p < 0.001 ). 21 patients (1.18%) received adjuvant chemoradiation, with a longer OS compared to patients with no adjuvant therapies (91.35 months vs. 59.47 months, p = 0.023). Adjuvant radiation did not significantly impact survival. Having moderately differentiated disease, stage II-III disease, private insurance, or Medicare predicted a higher likelihood of receiving surgery, while the presence of distant metastases was associated with a lower likelihood of receiving surgery (p < 0.001). Income status and facility type did not affect surgical receipt. Conclusions: This study affirms that surgery is the primary treatment for MSBA. Surgical resection was associated with improved OS, irrespective of the type of surgery. Adjuvant chemotherapy and chemoradiation also improved OS while adjuvant radiation did not significantly change OS. Having a lower grade or stage of disease, private insurance, or Medicare increased the likelihood of receiving surgery.