John Quiles, MD, is a board-certified gastroenterologist who recently joined our group after serving over 20 years in U.S. Army.  He spent his last 6 years at Brooke Army Medical Center as a key faculty member where he focused on endoscopic education and clinical research, training over 40 gastroenterologist and participating in multicenter studies to foster innovation to advance patient outcomes in the field of interventional endoscopy. 

Dr. John Quiles, specializes in interventional gastrointestinal endoscopy and helping patients with problems in the luminal GI tract (esophagus, stomach, duodenum and colon), the pancreas and biliary tract. He treats bile duct stones and strictures and routinely performs procedures such as endsoscopic retrograde cholangiopancreatography (ERCP) and/or endoscopic ultrasonography (EUS) for pancreaticobiliary strictures, stones, masses, cysts and other disorders. He also offers specialized ERCP and EUS procedures, including choledochoscopy, intraductal EUS, biliary radiofrequency ablation (RFA) and photodynamic therapy (PDT), laser lithotripsy and complex perihilar stenting, portal pressures gradient measurements, liver biopsy, cystgastrostomy, necrosectomy, and management of Barrett’s esophagus.   

Dr. Quiles has received specialized training and certification in the identification and endoluminal resection of precancerous and early GI cancers. He routinely performs endoscopic mucosal resection (EMR), endoscopic full thickness resection (EFTR), and endoscopic submucosal dissection (ESD) to remove large lesions in the GI tract. Dr. Quiles also performs peroral endoscopic myotomy (POEM) for patients with esophageal achalasia or Zenker’s diverticulum.  He is one of the few providers in San Antonio that can provide endoscopic bariatric therapy which can be performed either as a first-line treatment for weight loss (primary therapy) or as a follow-up to previous surgical procedures (secondary therapy).   Finally, he enjoys interventional hepatology and was the first provider in the Department of Defense to perform EUS guided portal pressures.

Dr. Quiles is an active member of various GI societies, and he is an active member of the American Society for Gastrointestinal Endoscopy (ASGE), the Association of Bariatric Endoscopy (ABE) and the American College of Gastroenterology (ACG).