Douglas Rex | |
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Nationality | American |
Alma mater | Harvard College Indiana University School of Medicine |
Occupation(s) | Physician, Professor of Medicine |
Known for | Research in colonoscopy |
Douglas Kevin Rex is an American gastroenterologist who teaches at Indiana University School of Medicine. [1] He is well known for his prolific publishing in the field of gastroenterology particularly in colonoscopy and colorectal cancer screening [2] and is widely regarded as one of the doctors who established colonoscopy as a safe and effective procedure. [3] He played a key role in Medicare reimbursement for colonoscopy resulting in adoption of the procedure as a colorectal cancer screening tool in the US. [4]
Rex returned to home state Indiana and enrolled at Indiana University School of Medicine in 1976 after graduating from Harvard College, in Cambridge, Massachusetts. As noted on the IU webpages, he remains loyal to his alma mater despite being in considerable demand all over the world. He has won many accolades including the Master Endoscopist Award (2003) [5] and Rudolf Schindler award (2013) from ASGE; [6] Berk-Fise clinical achievement award (2011) [7] from ACG. He is a past president and a Master of both the American Society of Gastrointestinal Endoscopy and the American College of Gastroenterology, [8] a Master of the American College of Physicians, [9] and is a Distinguished Professor of medicine at Indiana University since 2009.
Rex was born in Ligonier, Indiana and attended West Noble High School [10] before going on to Harvard College on a General Motors scholarship.
Rex graduated summa cum laude from Harvard and enrolled at Indiana University School of Medicine in 1976. After graduating with the highest distinction from medical school he pursued residency at the same school going on for a fellowship in gastroenterology and chief residency at one of the IU hospitals. Colonoscopy in the 1980s was still considered unsafe and screening programs were mostly limited to occult blood testing, which although extremely cheap, was not very accurate. Rex conducted the first population based study where he invited about 800 doctors and spouses in Indiana for screening colonoscopy. In addition to confirming the safety of the procedure, high polyp prevalence was noted which was replicated in later studies. More than two-thirds of colorectal cancer burden is the result of slowly progressing pre-cancerous polyps. Removal of at least larger of these polyps should therefore result in a decrease of colorectal cancer incidence. Colonoscopy screening for colorectal cancer was thus established in the United States. Rex is a major figure in the technical aspect of colonoscopy and his textbook on the procedure penned with Waye and Williams, remains the authority in that particular field. [11] His most widely cited study is a tandem colonoscopy study in which 183 patients underwent 2 colonoscopies on the same day. [12] The study brought to light that colonoscopy misses a significant percentage of pre-cancerous polyps. Since then Rex has been an international leader in the movement to improve the quality of colonoscopy performance. [13] [14]
Gastroenterology is the branch of medicine focused on the digestive system and its disorders. The digestive system consists of the gastrointestinal tract, sometimes referred to as the GI tract, which includes the esophagus, stomach, small intestine and large intestine as well as the accessory organs of digestion which include the pancreas, gallbladder, and liver.
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum. Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, abdominal pain and fatigue. Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous.
Colonoscopy or coloscopy is a medical procedure involving the endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a CCD camera or a fiber optic camera, which is mounted on a flexible tube and passed through the anus.
A polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated; if it is attached without a stalk, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, ear, sinus(es), urinary bladder, and uterus. They may also occur elsewhere in the body where there are mucous membranes, including the cervix, vocal folds, and small intestine. Some polyps are tumors (neoplasms) and others are non-neoplastic, for example hyperplastic or dysplastic, which are benign. The neoplastic ones are usually benign, although some can be pre-malignant, or concurrent with a malignancy.
An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others. Some adenomas grow from epithelial tissue in nonglandular areas but express glandular tissue structure. Although adenomas are benign, they should be treated as pre-cancerous. Over time adenomas may transform to become malignant, at which point they are called adenocarcinomas. Most adenomas do not transform. However, even though benign, they have the potential to cause serious health complications by compressing other structures and by producing large amounts of hormones in an unregulated, non-feedback-dependent manner. Some adenomas are too small to be seen macroscopically but can still cause clinical symptoms.
Fecal occult blood (FOB) refers to blood in the feces that is not visibly apparent. A fecal occult blood test (FOBT) checks for hidden (occult) blood in the stool (feces).
Familial adenomatous polyposis (FAP) is an autosomal dominant inherited condition in which numerous adenomatous polyps form mainly in the epithelium of the large intestine. While these polyps start out benign, malignant transformation into colon cancer occurs when they are left untreated. Three variants are known to exist, FAP and attenuated FAP are caused by APC gene defects on chromosome 5 while autosomal recessive FAP is caused by defects in the MUTYH gene on chromosome 1. Of the three, FAP itself is the most severe and most common; although for all three, the resulting colonic polyps and cancers are initially confined to the colon wall. Detection and removal before metastasis outside the colon can greatly reduce and in many cases eliminate the spread of cancer.
A stool test is a medical diagnostic technique that involves the collection and analysis of fecal matter. Microbial analysis (culturing), microscopy and chemical tests are among the tests performed on stool samples.
Virtual colonoscopy is the use of CT scanning or magnetic resonance imaging (MRI) to produce two- and three-dimensional images of the colon, from the lowest part, the rectum, to the lower end of the small intestine, and to display the images on an electronic display device. The procedure is used to screen for colon cancer and polyps, and may detect diverticulosis. A virtual colonoscopy can provide 3D reconstructed endoluminal views of the bowel. VC provides a secondary benefit of revealing diseases or abnormalities outside the colon.
Colonic polypectomy is the removal of colorectal polyps in order to prevent them from turning cancerous.
The stool guaiac test or guaiac fecal occult blood test (gFOBT) is one of several methods that detects the presence of fecal occult blood. The test involves placing a fecal sample on guaiac paper and applying hydrogen peroxide which, in the presence of blood, yields a blue reaction product within seconds.
A colorectal polyp is a polyp occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer.
Epithelial dysplasia, a term becoming increasingly referred to as intraepithelial neoplasia, is the sum of various disturbances of epithelial proliferation and differentiation as seen microscopically. Individual cellular features of dysplasia are called epithelial atypia.
Chromoendoscopy is a medical procedure wherein dyes are instilled into the gastrointestinal tract at the time of visualization with fibre-optic endoscopy. The purposes of chromoendoscopy is chiefly enhance the characterization of tissues, although dyes may be used for other functional purposes. The detail achieved with chromoendoscopy can often allow for identification of the tissue type or pathology based upon the pattern uncovered.
Blair S. Lewis, M.D., F.A.C.P., F.A.C.G., is an American board-certified gastroenterologist and Clinical Professor of Medicine at the Mount Sinai School of Medicine. Lewis is a specialist in the field of gastrointestinal endoscopy and was the primary investigator for the first clinical trial of capsule endoscopy for the small intestine and also the first clinical trial of capsule endoscopy for the colon.
The colorectal adenoma is a benign glandular tumor of the colon and the rectum. It is a precursor lesion of the colorectal adenocarcinoma. They often manifest as colorectal polyps.
Serrated polyposis syndrome (SPS), previously known as hyperplastic polyposis syndrome, is a disorder characterized by the appearance of serrated polyps in the colon. While serrated polyposis syndrome does not cause symptoms, the condition is associated with a higher risk of colorectal cancer (CRC). The lifelong risk of CRC is between 25 and 40%. SPS is the most common polyposis syndrome affecting the colon, but is under recognized due to a lack of systemic long term monitoring. Diagnosis requires colonoscopy, and is defined by the presence of either of two criteria: five or more serrated lesions/polyps proximal to the rectum, or more than 20 serrated lesions/polyps of any size distributed throughout the colon with five proximal to the rectum.
Juvenile polyps are a type of polyp found in the colon. While juvenile polyps are typically found in children, they may be found in people of any age. Juvenile polyps are a type of hamartomatous polyps, which consist of a disorganized mass of tissue. They occur in about two percent of children. Juvenile polyps often do not cause symptoms (asymptomatic); when present, symptoms usually include gastrointestinal bleeding and prolapse through the rectum. Removal of the polyp (polypectomy) is warranted when symptoms are present, for treatment and definite histopathological diagnosis. In the absence of symptoms, removal is not necessary. Recurrence of polyps following removal is relatively common. Juvenile polyps are usually sporadic, occurring in isolation, although they may occur as a part of juvenile polyposis syndrome. Sporadic juvenile polyps may occur in any part of the colon, but are usually found in the distal colon. In contrast to other types of colon polyps, juvenile polyps are not premalignant and are not usually associated with a higher risk of cancer; however, individuals with juvenile polyposis syndrome are at increased risk of gastric and colorectal cancer. Unlike juvenile polyposis syndrome, solitary juvenile polyps do not require follow up with surveillance colonoscopy.
Mark Pochapin is a gastroenterologist and educator whose work is focused on the prevention, early detection, and treatment of gastrointestinal cancers.
Kenneth Frank Binmoeller is a medical doctor and author of multiple scientific contributions and over 300 publications, as well as the inventor of the lumen-apposing metal stent (LAMS) and AXIOS System. These are medical devices used to relieve blockages while creating a direct connection between two bodily structures. He practices in the field of Gastroenterology with a specialty of Advanced Endoscopic Intervention. Binmoeller has been published for his innovations in medical devices and training in the field of Endoscopy.