Clinico-epidemiological Profile of Incidentally Detected Gastrointestinal Neuroendocrine Tumours on Gastrointestinal Endoscopy: A Retrospective Study

Introduction: Neuroendocrine tumours (NETs) are rare tumours, with the Gastrointestinal (GI) tract and the lung as the most common sites with indolent course. Endoscopists play a pivotal role in the diagnosis of GI-NETS because the majority of patients with NETs are asymptomatic and NETs are discovered during screening examinations. Since GI-NETs are less common than other cancers, their natural history, diagnosis, and treatment may not be completely understood.

Aim: To estimate the prevalence and to characterize the clinical, endoscopic, and histological features of incidentally detected GI NETs in nodular/polypoidal/ulcerated lesions on GI endoscopy.

Materials and Methods: This record-based retrospective study was conducted at the Department of Medical Gastroenterology of a tertiary care facility. The data belonged to the period between January 2018 to December 2020. Data belonged to the patients that underwent Oesophago- gastro duodenoscopy (OGD)/ Colonoscopy and were found to have nodular/ polypoidal lesions. Records on serum chromogranin, serum gastrin and radiological tests such as Ultrasonography(USG) or Computed Tomography (CT) scan were recorded. The histopathological with immunohistochemistry staining report was used to diagnose NETs. Continuous variables were analysed for normality by the Kolmogorov Smirnov test.

Results: A total of 59 eligible patients were studied. The prevalence of GI NET tumours in 2018 was 17 (0. 32%), 19 (0. 33%) in 2019, and 23 (0. 41%) in 2020 with an overall rate of 59 (0. 36%) for all the three years. Total male participants were 35 (59.32%), and the mean age of the patients was 56.13 ±12.44 years. Majority had abdominal pain (32, 54.24%) and 35(59.32%) had tumours in the duodenum, 15 (25.42 %) in the stomach. The most common site was duodenum 35 (59.32%). As per World Health Organisation (WHO) NET, most tumours were Grade I (50, 45.76%). Majority of tumours had Synaptophysin (57, 96.61%), Chromogranin (49, 83.05%), and a Ki67 (Kiel-clone no.67) index≤ 2 (49, 83.05%), while 27 (84. 75 %) tumours were of size of <1 cm.

Conclusion: GI-NETs are uncommon, and their biology, histopathology, and clinical behavior are distinct. Typically, they are slow-growing tumours, but their growth rate can fluctuate depending on the location, size, and grade of the tumour.