Clinical Features and Prognostic Factors of Duodenal Neuroendocrine Tumours: A Comparative Study of Ampullary and Nonampullary Regions

BACKGROUND Duodenal neuroendocrine tumours (DNETs) are rare neoplasms. However, the incidence of DNETs has been increasing in recent years, especially as an incidental finding during endoscopic studies. Regrettably, there is no consensus regarding the ideal treatment of DNETs. Even there are few studies on the clinical features and survival analysis of DNETs. AIM To analyze the clinical characteristics and prognostic factors of patients with duodenal neuroendocrine tumours. METHODS The clinical data of DNETs diagnosed in the First Affiliated Hospital of Air Force Military Medical University from June 2011 to July 2022 were collected. Neuroendocrine tumours located in the ampulla area of the duodenum were divided into the ampullary region group; neuroendocrine tumours in any part of the duodenum outside the ampullary area were divided into the nonampullary region group. Using a retrospective study, the clinical characteristics of the two groups and risk factors affecting the survival of DNET patients were analysed. RESULTS Twenty-nine DNET patients were screened. The male to female ratio was 1:1.9, and females comprised the majority. The ampullary region group accounted for 24.1% (7/29), while the nonampullary region group accounted for 75.9% (22/29). When diagnosed, the clinical symptoms of the ampullary region group were mainly abdominal pain (85.7%), while those of the nonampullary region groups were mainly abdominal distension (59.1%). There were differences in the composition of staging of tumours between the two groups (Fisher's exact probability method, P = 0.001), with nonampullary stage II tumours (68.2%) being the main stage (P < 0.05). After the diagnosis of DNETs, the survival rate of the ampullary region group was 14.3% (1/7), which was lower than that of 72.7% (16/22) in the nonampullary region group (Fisher's exact probability method, P = 0.011). The survival time of the ampullary region group was shorter than that of the nonampullary region group (P < 0.000). The median survival time of the ampullary region group was 10.0 months and that of the nonampullary region group was 451.0 months. Multivariate analysis showed that tumours in the ampulla region and no surgical treatment after diagnosis were independent risk factors for the survival of DNET patients (HR = 0.029, 95%CI 0.004-0.199, P < 0.000; HR = 12.609, 95%CI: 2.889-55.037, P = 0.001). Further analysis of nonampullary DNET patients showed that the survival time of patients with a tumour diameter < 2 cm was longer than that of patients with a tumour diameter >= 2 cm (t = 7.243, P = 0.048). As of follow-up, 6 patients who died of nonampullary DNETs had a tumour diameter that was >= 2 cm, and 3 patients in stage IV had liver metastasis. Patients with a tumour diameter < 2 cm underwent surgical treatment, and all survived after surgery. CONCLUSION Surgical treatment is a protective factor for prolonging the survival of DNET patients. Compared to DNETs in the ampullary region, patients in the nonampullary region group had a longer survival period. The liver is the organ most susceptible to distant metastasis of nonampullary DNETs.