Characteristics and risk factors for sporadic non-ampullary duodenal adenocarcinoma

Despite the gradual increase in the incidence of non-ampullary duodenal adenocarcinoma (NADAC), the associated characteristics and risk factors remain poorly understood. The aim of this study was to clarify the clinical characteristics and risk factors of sporadic NADAC.

In this retrospective case-control study, we enrolled 156 Japanese NADAC patients with 160 lesions from our hospital's cancer registry over 13 years. The patient demographics and clinical findings were compared to 468 age- and sex-matched controls selected from our medical health checkup recipients.

The ratio of men to women among the NADAC patients was 2:1, the median age was 64 years (range 31 to 90 years), the majority of the lesions were located in the second portion of the duodenum, and well-differentiated adenocarcinoma was the dominant histology. A univariate analysis revealed that smoking was a common risk factor for both men and women, whereas Helicobacter pylori (HP) infection and a history of colorectal cancer (CRC) were risk factors for the men. The multivariate analysis revealed that smoking, a history of CRC, and HP positivity were also individual risk factors for NADAC.

Smoking, a history of CRC, and HP positivity were identified as risk factors for NADAC.