Could a Camera in a Pill Replace the Colonoscopy?

The FDA recently granted clearance to a new method of capsule endoscopy, a means for a physician to see inside a patient’s colon to search for polyps without the more invasive colonoscopy. The patient swallows a pill the size of a large vitamin. Inside the pill is a camera which takes pictures as it moves through the patient’s digestive system and transmits them to the physician. The device is called the PillCam® Colon 2 Capsule Endoscopy System. The FDA classified the device de novo as Class II. The use of the term “de novo” indicates that the developer determined that there was no other approved device against which to compare it and a request for initial classification pursuant to Food, Drug and Cosmetic Act (FDCA) sec. 513(f). Class II means that the device is considered safe within certain limits and subject to specific, special controls.

The developer, Given Imaging  (Given), is an Israeli firm. It previously developed capsule endoscopy devices for examination of the esophagus (the PillCam EO) and the small bowel (PillCam SB).

Special Controls

The FDA determined that premarket approval (PMA) will be required before Given may market the device.To obtain PMA, Given must present satisfactory evidence of:

  • biocompatibility, i.e., the device will not cause adverse reactions in the patient’s tissue;
  • electrical, thermal, and mechanical safety, addressing the possibility that the device may malfunction;
  • electromagnetic compatibility (lack of interference) with other electronic devices;
  • compatibility and secure communication between the camera, transmitter, and recorder;
  • accurate and complete image acquisition;
  • adequate battery life; and
  • accurate interpretation of the images.

These matters must be addressed through clinical and nonclinical testing and through appropriate labeling. For example, the labeling should provide instructions to both doctors and patients on the preparation required, signs of possible malfunction, and what to do if they suspect that the device has malfunctioned or has not been excreted.  The images transmitted from the camera must be compared to the images from colonoscopy to determine the likelihood that the PillCam will miss polyps that the colonoscopy would reveal or appear to find polyps that are not there.

Terms of Clearance, Consumer Hopes

Anyone who has undergone a colonoscopy would probably consider the PillCam an attractive option. The colonoscopy is invasive and requires sedation. Given expects that the device eventually will be approved for routine screening. But the FDA clearance is limited to use with patients who have undergone an incomplete optical colonoscopy with adequate preparation,  where it was not technically possible to complete the evaluation. The device was approved in Japan in July 2013 with similar restrictions.

The PillCam is significantly less expensive than colonoscopy, costing about $500 compared to $4,000 or so. Patients can continue most normal activity while testing, although they must avoid sources of electronic interference, such as MRI machines.  If it were approved for general screening, patients with lower incomes and substandard  benefits might find the PillCam more feasible.  But the PillCam Colon is not as effective at detecting polyps and adenomas. In a 2009  study published in the New England Journal of Medicine  (NEJM), 322 patients had a capsule endoscopy using the PillCam, followed by a colonoscopy several hours later after the capsule was excreted. The colonoscopy revealed polyps in 212 patients; about 64 percent were found on analysis of the PillCam transmission. Cancers were detected by colonoscopy in 19 patients; the PillCam found 14 of them. Similarly, 52 patients had one or more advanced adenomas according to the colonoscopy; 44 of them showed up in  the capsule endoscopy.

Another reason why capsule endoscopy may not become a substitute for colonoscopy is the preparation. Many people consider the bowel cleansing process before colonoscopy unpleasant. According to the NEJM article, the preparation needed for a capsule endoscopy is “more extensive” because of the need too propel the capsule through the digestive tract.