Small Bowel Adenocarcinoma: a Nationwide Population-Based Study

Purpose: Small intestinal cancers have a non-specific clinical presentation and hence a delayed diagnosis. The prevalence of small intestinal cancers is low, and there are no cost-effective methods of screening. This study aimed to identify clinical characteristics of duodenal and jejunal adenocarcinomas that can assist in the early detection and diagnosis of disease.

Methods: Duodenal adenocarcinoma and jejunal adenocarcinoma in Explorys database (1999-2019) were compared using odds ratio (OR) with 95% confidence intervals. Data on demographic characteristics, risk factors, clinical features, and treatment were collected.

Results: Out of a total of 8100 patients with a diagnosis of primary adenocarcinoma of the small intestine, 5110 are primary adenocarcinoma of duodenum (63%), and 600 are primary adenocarcinoma of jejunum (7.4%). Patients with jejunal adenocarcinoma when compared with patients with duodenal adenocarcinoma are more obese (OR, 1.36) and have a significantly higher prevalence of malignant neoplasm of colon (OR, 3.07), Crohn's disease (OR, 4.42), and celiac disease (OR, 2.48). Jejunal adenocarcinoma patients presented more frequently with intestinal obstruction (OR, 1.99), whereas duodenal adenocarcinoma patients more commonly presented with iron deficiency anemia (OR, 0.16). Patients with jejunal adenocarcinoma are less likely to undergo therapy with anti-neoplastic agents when compared with duodenal adenocarcinoma (OR, 0.81). There are no differences in patients undergoing surgical intervention or a combination of surgical intervention and antineoplastic therapy.

Conclusions: Jejunal adenocarcinoma is more commonly associated with colorectal cancer, celiac disease, and Crohn's disease. They also had lower odds of requiring chemotherapeutic agents.