John Sun, M.D., specializes in uncommon and difficult digestive cases involving patients with small bowel disorders such as Inflammatory Bowel Disease (IBD), some of whom have suffered with symptoms for years without relief. Dr. Sun performs a technique known as single-balloon enteroscopy and is proud to return to Topeka and offer this procedure to patients for the diagnosis and treatment of small bowel diseases. This highly specialized and unique endoscopic procedure uses a balloon-assisted enteroscope, which provides unprecedented visualization of lesions and abnormalities in the small bowel, and has the ability to allow non-surgical treatment and biopsy of small bowel pathology. Through single-balloon enteroscopy, many treatments of the small bowel are now possible including stricture dilation, polyp removal, tissue sampling, and various hemostatic procedures to stop active blood loss or destroy bleeding lesions. Dr. Sun was one of the first physicians in the country to perform this procedure.
Cotton O’Neil is proud to announce that Dr. Sun has joined our medical team and will practice as a gastroenterology physician. His practice will be located at Cotton O’Neil Digestive Health Center, 720 S.W. Lane St. in Topeka. Dr. Sun previously worked at the University of Kansas Medical Center in Kansas City as an assistant professor of medicine from 2013 to 2016 and also at Kansas Medical Clinic in Topeka from 2012 to 2013. From 2005 to 2012 he practiced at Kaiser Permanente San Francisco and was also clinical assistant professor of medicine at the University of California, San Francisco, one of the nation’s top academic medical centers.
Dr. Sun received his medical degree at Temple University School of Medicine, Philadelphia, Pennsylvania, in 1999. He completed a categorical internal medicine residency at Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, in 2002. He completed a gastroenterology fellowship at the Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, in 2005.
“Making your patients better is what keeps me going,” said Dr. Sun. “There is no greater satisfaction than treating a patient who has been through multiple treatments and has had several procedures with no relief, but then tells you ‘I haven’t felt this good in years!’”
Running and photography are two passions that Dr. Sun enjoys in his spare time. He has an eye for abstract architecture, and his photography has been on exhibit in both the NOTO Arts District in Topeka and in San Francisco, California.
Tanner Speake, PA-C, has also joined the medical team and will be 
available to see new patients at the Cotton O’Neil Digestive Health Center. Speake received his master of science in physician assistant studies at the University of Florida, Gainesville, Florida, in 2016. He received his bachelor of arts in kinesiology at Washburn University in Topeka in 2013.
Dr. Sun and Tanner Speake are now accepting new patients.