# Principles of Endoscopic Surveillance of Extrapapillary Duodenal Lesions in Familial Adenomatous Polyposis: A 14-Year Single-Center Observation

## TL;DR

This study shows that regular endoscopic monitoring and removal of duodenal polyps in FAP patients can prevent cancer and reduce the need for surgery.

## Contribution

The study provides 14 years of observational data on endoscopic surveillance of extrapapillary duodenal lesions in FAP patients.

## Key findings

- No invasive duodenal cancer was detected, but five patients had high-grade dysplasia.
- Routine polypectomy led to a temporary decrease in disease severity according to the Spiegelmann score.
- Endoscopic therapy reduced the need for surgical interventions in managing extrapapillary lesions.

## Abstract

Familial adenomatous polyposis (FAP) is a hereditary condition that causes numerous polyps in the digestive tract and significantly increases the risk of cancers. While most attention is given to the lesions in the colon, this study focuses on those located in the duodenum, outside the ampulla of Vater, which are often overlooked despite their cancerous potential. Over 14 years, we monitored 45 patients with FAP through regular endoscopic surveillance, aiming to detect and remove high-risk polyps before they could become malignant. Our findings indicate that consistent endoscopic surveillance and removal of these lesions may prevent invasive cancer and lead to a reduction in disease severity over time. This research highlights the importance of targeted, long-term monitoring of extrapapillary duodenal lesions and may also help with management strategies that could reduce the need for major surgeries among these patients.

Background: In patients with familial adenomatous polyposis (FAP), the duodenum is another high-risk region for malignancy after the large bowel. However, endoscopic and surgical management differs for papillary lesions and adenomas located in other parts of the duodenum. The aim of the study was to present the principles of the endoscopic surveillance of extrapapillary polyps based on a single-center 14-year observational study. Methods: The retrospective analysis was carried out in 2010–24 on a group of 45 people enrolled in endoscopic surveillance of the upper gastrointestinal tract due to FAP. The evaluation was aimed at detecting the malignant transformation of extrapapillary duodenal adenomas, with a radical removal of high-risk lesions. The severity of polyposis in the subsequent years of observation as well as the effectiveness of routine polypectomy on downstaging according to the Spiegelmann score were also assessed. Results: Invasive duodenal cancer was not detected in any case; however, high-grade dysplasia (HGD) was confirmed in five patients. The severity of polyposis and the number of polyps with HGD increased in following examinations, but routine polypectomy performed mainly during the 4th and 5th endoscopies allowed for a transient decrease in the Spiegelman score. Finally, progression of duodenal polyposis was observed in 18 patients, another 4 experienced regression (downstaging) and in 23 cases the stage of severity did not change. In addition, five patients were diagnosed with LST-G lesions, which were removed without recurrence. Conclusions: The patient’s age correlates with the severity of polyposis and the risk of malignancy, but routine endoscopic resections eliminate potentially invasive lesions and contribute to disease regression expressed by the Spiegelmann score. The radical endoscopic therapy of extrapapillary duodenal lesions limits the indications for surgical procedures.