Flat/Depressed Colon Lesions - May 27, 2008 Newsletter

Flat/Depressed Colon Lesions Colorectal Cancer Screening and Colonoscopy Procedure By Jennifer Lynn Bonheur, MD

EHE Newsletter, Volume 8, Number 127 May 27, 2008

Abnormal growths in the form of flat or depressed mucosal lesions have been identified as bearing significant risk for the development of colorectal cancer. While they have been recognized for the past several decades and are known to be a much less common finding, recent attention in the news followed a study which reported that flat/ depressed mucosal lesions were more likely to be pre-cancerous as compared to the more typical protuberant polyps. Most gastroenterologists have been aware of these lesions for many years and are trained in the techniques required to resect them.

The Importance of Colorectal Cancer Screening

Although colorectal cancer is highly preventable, it is the second most common cause of cancer deaths in the United States. In addition to age-appropriate screening, symptoms and signs which raise concern and should prompt further evaluation include rectal bleeding, change in bowel habits, lower abdominal pain, unintentional weight loss, and iron deficiency anemia. Proper screening can help reduce mortality rates at all ages, and colonoscopy plays an important role in this effort.

Colonoscopy Procedure

Colonoscopy enables visual inspection of the entire large bowel from the distal rectum to the cecum (approximately 3-5 feet). The procedure is a safe and effective means of evaluating the large bowel. It is performed by physicians who are specially trained in diagnosing diseases of the gastrointestinal tract. The technology for colonoscopy has evolved to provide a very clear image of the mucosa through a long, flexible, fiberoptic videocamera (a colonoscope). The camera connects to a computer, which can store and print color images selected during the procedure. The colonoscope has channels through which instruments can be passed in order to perform biopsies, remove polyps, or cauterize bleeding. Air, water, and suction can be applied to help provide a clear visual field for inspection. Compared with other imaging modalities, colonoscopy is especially useful in detecting small polyps and flat lesions. In addition, colonoscopy allows for immediate intervention, as biopsies can be taken and polyps removed as they are detected.

Polyps are abnormal growths that can be found anywhere throughout the lumen of the colon and rectum. They vary in size, shape and histology, may be single or multiple, and typically protrude into the lumen. The incidence of polyps increases with age. While most are benign and generally asymptomatic, some may have a pre-malignant potential and are believed to be the precursors to most colorectal cancers.

To maximize visualization and safety during the procedure, the colon must be completely empty prior to colonoscopy. Several options are available for pre-colonoscopy bowel cleansing. It is not uncommon for patients to report an inability to tolerate the colon-cleansing preparation often secondary to unpalatable taste and large volume of the preparation, nausea, abdominal cramping and bloating. It is recommended that the preparation be placed in the refrigerator one day prior to using. Patients may also try adding sugar-free flavor packets in an attempt to improve the taste of the polyethylene glycol solution. The rate of ingestion of the cleansing agent by patients is not as important as ensuring that the solution has been taken in its entirety. Evidence of a complete preparation is the passage of clear, colorless stool. Regardless of the laxative method used, it is recommended that patients drink at least fourteen 8-ounce glasses of water or clear beverages during the day prior to colonoscopy to prevent dehydration.

Patients receive medication at the start of the procedure which is intended to keep them comfortable throughout the exam and may prevent them from having a clear memory of the procedure. Patients are monitored throughout the procedure to reduce the risk of sedation related complications. With the patient positioned on their left side, the colonoscope is inserted through the rectum into the colon. The scope is gently advanced and maneuvered while the lumen and walls of the colon are carefully inspected via images projected onto a video monitor.

Risks of the procedure are rare and include bleeding and perforation (tear) of the colon wall. More commonly, patients may experience abdominal bloating and cramping for a few hours post-procedure. This is a consequence of air which is used to inflate the colon to enable visualization during the exam and can be easily expelled to relieve this discomfort. Persistent pain after a colonoscopy should be brought to the attention of a physician. Patients can generally resume oral intake immediately after their procedure but are advised not to drive for several hours after receiving intravenous sedation.

The potential life-saving benefits of having a colonoscopy greatly outweigh minor patient comfort. EHE International's Medical Advisory Board recommends that men and women have a baseline screening at age 40 or earlier when specific personal health or family health risks factors are presented. The interval between colonoscopies is determined on an individual basis for patients, again, depending on family history and/ or personal history of colon cancer or colon polyps. If you have questions regarding your need to have a screening or surveillance colonoscopy, please ask your doctor.

Excerpts taken from: Bonheur JB. Colonoscopy. Serial available on-line at www.emedicine.com

About the Author: Jennifer Bonheur,MD, is the Senior Gastroenterologist at EHE International. After receiving a B.A. from New York University, College of Arts and Sciences, she attended State University of New York at Stony Brook School of Medicine. She completed internship, residency, chief residency, and fellowship in gastroenterology at Lenox Hill Hospital. She has conducted both clinical and laboratory research and has published many scientific articles. In addition to her work at EHE, she has a private practice of gastroenterology in NYC.

MEDICAL DISCLAIMER: The information is not intended to constitute medical advice and is not a substitute for consultation with a physician or other health care provider. Individuals with specific complaints should seek immediate consultation from their personal physicians.