BOSTON (Reuters) - A swallowed capsule that takes pictures of the colon as it passes through misses too many pre-cancerous lesions and is not ready to replace more traditional colonoscopies, Belgian researchers reported on Wednesday.
The Given Imaging PillCam, containing tiny video cameras at each end of a 3 cm-long (1.2-inch) capsule, detects some colon tumors and polyps but missed five of the 19 tumors found in patients who were also checked with a colonoscopy, the researchers reported in the New England Journal of Medicine,.
The PillCam technique, actively marketed in Europe but still considered experimental in the United States, also missed more than one quarter of polyps and pre-cancerous lesions, known as adenomas, that were larger than 6 millimeters (0.23 inch).
"Since the size of colorectal lesions is a predictor of the development of cancer, the relatively lower sensitivity of capsule endoscopy for the detection of large adenomas is cause for concern," Dr. Michael Bretthauer of Oslo University Hospital in Norway wrote in a commentary on the study.
Doctors are looking for an easier way to screen for colorectal cancer, the third leading cause of cancer deaths in the United States and an important cause globally.
The best method, a colonoscopy, uses a lit tube inserted into the colon. But preparing for the test can be uncomfortable and the procedure requires anesthesia or sedation. In rare cases, the colon may be punctured. Only about half of the people who should get one actually do.
Dr. Andre Van Gossum of Erasme University Hospital in Brussels and colleagues tested the Israel-based Given's PillCam in 320 people.
The capsule did well at finding small abnormalities, so it may work well in combination with a so-called virtual colonoscopy, which uses a computer enhanced X-ray called a CT scan, Van Gossum said.
The PillCam for the colon "is probably not ready to be recommended as a screening procedure. But the results are quite encouraging," Van Gossum said in a telephone interview.
Given, which also makes a PillCam for the small intestine, paid for the study.
The capsule examination costs about the same as a colonoscopy. But if suspicious polyps are found, a colonoscopy is still needed to remove them.
"With the capsule's relatively low sensitivity for the detection of colorectal lesions, its requirement for more extensive bowel-cleansing regimens as compared with colonoscopy and CT colonography, and its high cost, colon capsule endoscopy cannot be recommended at this time," Bretthauer wrote.
The capsule takes pictures for three minutes after being swallowed, providing images of the esophagus and stomach. Then it turns itself off for 105 minutes to preserve the battery while is passes through most of the small intestine on its way to the large bowel.
It generally took as little as four minutes and as long as eight hours for it to pass through the colon, although in one patient it stayed in the body for nearly a month.
Van Gossum said he did not think the findings are a setback for the capsule technique and hopes the technology will improve.
Editing by Maggie Fox and Bill Trott