New, less invasive colonoscopy more tolerable but less reliable

A new medical procedure to find polyps in the colon may hold promise, but kinks still need to be worked out, according to a report in MedPage Today.

The new procedure, called a capsule colonoscopy, offers an alternative to the traditional colonoscopy in which a patient undergoes a bowel cleansing process before going under local anesthesia and having a flexible telescopic camera passed through the rectum and bowel. During a capsule colonoscopy, patients still go through a bowel cleansing process but then swallow a small video capsule that examines the colon for polyps as it passes through the bowel. The capsules are excreted – typically within 10 hours.

According to an investigational study of the capsule colonoscopy, the safety and tolerability of the new procedure was good and no adverse events were attributed to the capsule. Patients involved in the trial also said they tolerated the capsule method better than the traditional one. However, the bowel preparation for the capsule was not as good as conventional colonoscopy, with a 55 percent good-to-excellent rating. And, the sensitivity for detecting large polyps “was not optimal” at just 55 percent.

Doctors say the less-than-adequate bowel preparation for the capsule procedure may be due to the amount of fluids that can be aspirated during a conventional colonoscopy but not during the capsule procedure.

Patients in the trial started a low-residue diet three days prior to the capsule procedure. They also ingested three liters of polyethylene glycol the day before and another liter the morning of the procedure. Polyethylene glycol is a laxative sold under the brand names GoLytely, GlycoLax and MiraLAX. After the capsule was swallowed, the patients took the anti-nausea drug domperidone and sodium phosphate to help move the capsule through the bowel.

Sodium phosphate is a laxative that has been sold over-the-counter under the brand name Fleet Phospho-Soda. That product, as with other sodium phosphate products, have recently received a warning by the Food and Drug Administration (FDA) for the increased risk of acute phosphate nephropathy, a form of acute kidney injury associated with deposits of calcium phosphate crystals in the renal tubes that may result in permanent renal function impairment.

The capsule colonoscopy is not FDA approved and is still being investigated as an alternative to traditional colonoscopy. Better bowel preparation, improved capsules and better training for the capsule endoscopists have been listed among areas that need improvement.