The GENTLENESS study is a prospective, multicenter, observational registry designed to evaluate the endoscopic management of patients with suspected biliopancreatic and periampullary neoplastic diseases within the Pancreas Units network of the Lombardy Region.

Patients undergoing endoscopic ultrasound (EUS) for suspected pancreatic or periampullary malignancies, including pancreatic ductal adenocarcinoma, pancreatic neuroendocrine tumors, cystic pancreatic neoplasms requiring endoscopic, surgical, or oncological management, and periampullary tumors of the distal bile duct, ampulla, or duodenum, will be prospectively enrolled according to standard clinical practice.

The study aims to assess the diagnostic accuracy of EUS-guided tissue acquisition, procedural safety, the need for repeat sampling, and organizational performance indicators, including time to definitive cyto-histological diagnosis and time to initiation of disease-specific treatment. No additional procedures beyond routine clinical care will be performed as a result of study participation.

Despite advances in oncological therapies, pancreatic cancer remains one of the leading causes of cancer-related mortality worldwide, with an increasing burden projected over the coming decades. The diagnostic and therapeutic pathway of biliopancreatic malignancies is complex and requires a high level of multidisciplinary expertise, particularly in high-volume referral centers organized as Pancreas Units.

Endoscopic ultrasound (EUS) plays a central role in the diagnostic work-up of biliopancreatic and periampullary lesions, allowing high-resolution morphological assessment and, when indicated, tissue acquisition through fine-needle aspiration (FNA) or fine-needle biopsy (FNB). Accurate histological diagnosis is essential for therapeutic decision-making, including surgical planning, systemic therapy, and molecular profiling.

The Lombardy Region has adopted a Hub-and-Spoke organizational model for Pancreas Units, defining minimum procedural volumes, expertise requirements, and performance benchmarks for referral centers. However, a centralized prospective system for monitoring endoscopic activity, diagnostic performance, and procedural outcomes across these centers is currently lacking.

The GENTLENESS study has been designed to prospectively collect real-world data on EUS procedures performed in Lombardy Pancreas Unit Hub centers, with the primary objective of evaluating the diagnostic accuracy of EUS-guided biopsies. Secondary objectives include assessment of procedural volume, sampling techniques, need for repeat biopsies, complication rates, and time intervals from procedure to definitive diagnosis and initiation of treatment.

The study is observational, does not introduce changes to clinical practice, and reflects routine patient management pathways. Any future analyses beyond the scope of the present registry will require separate Ethics Committee approval.

Inclusion Criteria:

• Adults (≥18 years)
• Clinical, biochemical, and/or imaging suspicion of pancreatic neoplasia (adenocarcinoma, neuroendocrine tumors, cystic neoplasms requiring endoscopic, surgical, or oncological treatment) or periampullary neoplasia (distal bile duct, ampulla, duodenum)
• Candidate for EUS according to standard clinical practice
• Ability to understand and sign informed consent

Exclusion Criteria:

• Age <18 years
• Pregnancy or breastfeeding
• Conditions other than those defined in the inclusion criteria
• Inability to provide informed consent
• Refusal to participate in the study

All consecutive patients referred to participating Pancreas Unit Hub centers for EUS evaluation of suspected biliopancreatic or periampullary neoplastic disease, who meet eligibility criteria and provide informed consent.