A colonoscopy is an endoscopic procedure that provides a direct, visual examination of the entire large intestine, which includes the colon and the rectum. A physician inserts a long, flexible tube equipped with a camera and light source into the anus to inspect the inner lining of the bowel. This procedure is fundamental in preventative medicine because it allows for the detection and removal of precancerous growths called polyps before they develop into colorectal cancer. It is a widely recommended screening tool for adults.
The Specialists Who Perform Colonoscopies
The medical professional most commonly associated with performing a colonoscopy is a gastroenterologist. This physician completes a three-year internal medicine residency, followed by a specialized three-year fellowship focused on the digestive tract. This training provides deep expertise in recognizing subtle abnormalities, managing complex polyps, and handling potential complications.
Colorectal surgeons, who are general surgeons with an additional fellowship in colon and rectal surgery, also routinely perform colonoscopies. These specialists are particularly involved when a patient has a history of colorectal cancer, complex polyps requiring advanced removal techniques, or inflammatory bowel diseases. While both specialties are highly qualified, a colorectal surgeon’s practice often centers on surgical intervention, whereas a gastroenterologist’s practice focuses on medical management and endoscopy.
Some primary care physicians, such as family medicine doctors, may also perform screening colonoscopies, especially in rural or underserved areas where access to specialists is limited. Their ability to perform the procedure is based on documented training and competency. However, studies suggest that gastroenterologists are less likely to miss lesions and have lower complication rates compared to other physicians who perform the procedure in lower volumes.
Indications for the Procedure
A patient is referred for a colonoscopy for one of two main reasons: screening or diagnosis. A screening colonoscopy is a preventative measure performed on individuals who have no symptoms and are considered to be at average risk for colorectal cancer. Current guidelines recommend that average-risk individuals begin screening at age 45 to detect polyps before they become cancerous.
A diagnostic colonoscopy is performed to investigate specific symptoms or abnormal findings from another test. These symptoms may include unexplained rectal bleeding, chronic abdominal pain, a persistent change in bowel habits like new-onset constipation or diarrhea, or unexplained iron-deficiency anemia. The procedure is also used for surveillance for patients who have previously had polyps removed or have a personal history of inflammatory bowel disease.
The interval for surveillance colonoscopies is determined by the size and type of polyps previously found, as well as the quality of the prior bowel preparation. For instance, a patient with a normal screening result is typically advised to return in ten years, while someone with a history of certain adenomas may need a follow-up in three to five years.
Vetting and Selecting a Provider
When selecting a provider, it is helpful to look beyond the general specialty and focus on specific quality metrics. The most important objective measure is the Adenoma Detection Rate (ADR), which is the percentage of patients screened who have at least one precancerous polyp detected and removed. Current guidelines suggest that a physician’s ADR should be at least 25% overall.
Another strong indicator of a thorough examination is the average withdrawal time, which is the time spent systematically inspecting the colon lining as the scope is pulled back. An average withdrawal time of at least six minutes during a procedure where no polyps are found is considered a benchmark for a careful inspection. Patients can ask their doctor for their personal ADR and average withdrawal time.
It is also important to consider the facility where the procedure is performed, whether it is an ambulatory surgery center (ASC) or a hospital setting. Accredited ASCs often specialize in outpatient procedures, which can lead to a more streamlined patient experience. Finally, patients should confirm that the physician is board-certified in their specialty.