Retrospective study to analyze benign complications and malignancy risks after ERCP with sphincterotomy. All patients who received a ERCP with sphincterotomy for a benign disease will be included. Post-ERCP hepato-biliary complications in the follow-up will be registered.

This is a single center retrospective study. All patients that received an ERCP with sphincterotomy for a benign disease from 1995 will be included.

The exclusion criteria are diagnosis of primary malignant tumors in the liver, bile ducts including peri-ampullary region and pancreas in the ERCP. Loss of follow-up less than two years after the ERCP and biliopancreatic malignancy diagnostic in this period. The initial work-up included laboratory test, ultrasound scan and, when precise, computed tomography (CT) and magnetic resonance image (MRI).

The data collected will be:

1. Age, sex, comorbidities, long of hospital stay.
2. ERCP indications.
3. ERCP sphincterotomy or precut, biliary stent insertion and type of stent.
4. post-ERCP diagnosis, abnormal diameter of biliary tree.
5. ERCP repetition and causes.
6. Immediate complications like bleeding, residual choledocholithiasis, ascending cholangitis, pancreatitis, and cholecystitis, and their number after more than two months.
7. Malignant complications after more than two years: cholangiocarcinoma, hepatocarcinoma and ductal pancreatic adenocarcinoma.

Stistical analyses will be performed using SPSS, ver. 25.0 (SPSS Inc., Chicago Illinois, USA). The demographics, perioperative data, operation details, length of hospital stay, morbidity, mortality and pathologic and oncological outcomes are expressed as numbers and percentages for qualitative variables and medians and interquartile ranges (IQRs) for quantitative variables.

Univariate and multivariate logistic regression analyses will be employed to determine the risk factors for the development short-term and long-term complications. Variables with P<0.1 in the univariate analysis will be further introduced into the multivariate analysis with the Wald selection method. P values < 0.05 were considered statistically significant.

This study involved the use of data from clinical records. To guarantee the proper handling of the information, the data were treated confidentially and anonymously according to the provisions of the Spanish Organic Law 15/1999, of 13 December 1999, on Personal Data Protection (LOPD). All methods were performed in accordance with the guidelines and regulations established by the Declaration of Helsinki (1964, revised in 1983) on biomedical research in humans, the Spanish Royal Decree 1090/2015, of December 4, which regulates clinical trials with drugs, the Research Ethics Committees with drugs and the Spanish Registry of Clinical Studies. Ethical approval from the Clinical Trials and Ethics Committee of Valladolid University was granted.

Inclusion Criteria:

• Patients having undergone ERCP with sphincterotomy for benign diseases between 1995 and 2015

Exclusion Criteria:

• Diagnosis of primary malignant tumors in the liver, bile ducts including ampullary region, and pancreas in the ERCP test.
• Patients with follow-up less than two years after the ERCP and biliopancreatic malignancy diagnostic in this period.

Patients having undergone ERCP with sphincterotomy for benign diseases between 1995 and 2015