Swallowed capsule falls short for colon cancer test

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 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.

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New Target Eyed for Colon Cancer Drugs

Drugs that target a cell surface molecule called ERBB3 could offer a more effective way to treat colon cancer, a new study suggests.

Currently, drugs that target the epidermal growth factor receptor (EGFR) are used to treat a number of cancers, but these drugs haven't proven very effective against colon cancer. ERBB3 is closely related to EGFR. Drugs aimed at ERBB3 may be much more effective than EGFR inhibitors at treating colon cancer.

In this study, researchers genetically blocked ERBB3 in mice with colon cancer and in human colon cancer cells.

"If you genetically remove ERBB3, as you would if you were pharmacologically targeting it, then the mice rarely develop colon cancer," lead author David Threadgill, adjunct professor in the department of genetics at the University of North Carolina at Chapel Hill and a professor in the genetics department at North Carolina State University, said in a news release.

He and his colleagues also found a dramatic increase in cell death when ERBB3 was genetically removed from human colon cancer cell lines.

"If we can use an inhibitor to block ERBB3, then it should be a very potent anti-cancer therapy," Threadgill said.

The study appeared online Aug. 17 in the Journal of Clinical Investigation.

Source : health.usnews.com

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Colonoscopy Beats 'Camera Pill' at Catching Colon Cancer

Researchers had high hopes for a minimally invasive cancer-screening technique known as capsule endoscopy, but the "camera pill" appears to be less effective than standard colonoscopy at identifying precancerous polyps and cancer, new research from Belgium suggests.

Although able to identify many lesions and cancers, the relative underperformance of capsule endoscopy -- in which a patient swallows a tiny, battery-operated, excretable capsule fitted with a double-sided video camera -- suggests that for now the more invasive colonoscopy should remain the gold standard for colorectal cancer detection.

"Although this study shows encouraging results, the use of the colon capsule can not be recommended at this stage for colon screening," said study lead author Dr. Andre Van Gossum from the department of gastroenterology at Erasme University Hospital at the Free University of Brussels.

The findings were published in the July 16 issue of the New England Journal of Medicine.

The study involved more than 300 patients who were scheduled to undergo a colonoscopy at one of eight medical centers, because they either had a history of colon cancer (about one-third of the patients) or were suspected of having the disease (about two-thirds of the patients). The patients underwent capsule endoscopy and, after that, conventional colonoscopy.

Participants ranged in age from 22 to 84 (average age was nearly 59), and 55 percent were men.

The researchers determined that capsule endoscopy -- which does not require sedation -- is indeed a safe and less invasive technique for visualizing the colon.

Technically, the colon capsule functioned as intended in nearly 98 percent of patients, the team found. The pill was deemed easy-to-swallow, and none of the patients experienced any problems excreting the capsule. Nearly 93 percent did so within 10 hours of ingestion and before the pill's battery-life was exhausted. On average, travel time for capsule navigation through the full length of the gastrointestinal tract -- from mouth to anus -- was calculated at four hours.

Most side effects were observed as mild and passing, and related not to the pill ingestion itself but to the bowel-prep requirements. Described as more extensive than colonoscopy preps, this involves swallowing liquids designed to clean the colon and optimize pill movement and imaging.

The effectiveness of the colon capsule was directly related to how well the patients had cleaned their colons. Detection sensitivity was significantly worse among those patients with poor or fair colon cleanliness than those with good or excellent cleanliness.

Also, the pill procedure detected only 64 percent of polyps 6 millimeters in size or larger that were identified by standard colonoscopy. And with similarly sized advanced cancer, capsule screening captured just 73 percent of adenomas that were spotted by colonoscopy.

Of 19 confirmed cases of colon cancer uncovered through colonoscopies, just 14 were caught by the pill technique, the researchers noted.

The authors therefore concluded that capsule endoscopy is currently inferior to colonoscopy as a screening method, but they called for more research.

The noninvasive character of this technique has the potential to encourage more patients to get screened for colon cancer, Van Gossum said. In time, "technological improvements, as well as adapted protocol for colon preparation, could increase the sensitivity of this new method," he noted.

Dr. Felice Schnoll-Sussman, director of research with the Jay Monahan Center for Gastrointestinal Health at the New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City, said the capsule does have value, despite seemingly significant deficiencies in identifying both polyps and cancers.

"The results were still admirable in terms of what colon capsules were able to identify," she observed. "And although the prep for the capsule exam is more arduous than the prep for a colonoscopy, it seems that the experience was viewed as convenient, safe and tolerable."

"I think that in certain patient populations --those incapable of undergoing a colonoscopy because they are very difficult to sedate, or those that are just not willing to undergo a colonoscopy -- this may be an appropriate alternative," she said. "But patients will have to weigh the options, recognizing that the accuracy of colon capsule detection is lower."

Source : www.drugs.com

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Colon Cancer Gene Test Can Predict Disease Return

A gene test for colon cancer, developed by Genomic Health Inc., can help alert patients their cancer may recur after surgery, giving them a chance to protect themselves with chemotherapy, researchers said.

The test, called Oncotype DX for colon cancer, sifts through patients’ tumor cells for a telltale pattern of genes that indicate a two-fold increased risk of relapse, according to a study previewed yesterday by the American Society of Clinical Oncology. The test failed to predict whether chemotherapy drugs would actually work for high-risk patients.

Doctors can’t absolutely predict when colon cancer, diagnosed in 146,970 Americans yearly, might return in early- stage patients. While the new test may be useful “as a tie- breaker” in patients whose need for chemotherapy is unclear, it isn’t the final answer, said Alan Venook, professor of medicine at the University of California San Francisco.

“You got half a loaf, instead of a whole loaf,” said Venook, who has consulted for Genomic Health, in a telephone interview yesterday.

The study, led by David Kerr at the University of Oxford in England, is one of about 4,000 presentations planned for the American Society of Clinical Oncology’s annual meeting May 29 to June 2 in Orlando, Florida.

Genomic Health of Redwood City, California, plans to launch Oncotype DX for colon cancer in early 2010, said Emily Faucette, a company spokeswoman. The company already markets a similar gene test for breast cancer, at a cost of $3,820, to gauge risk of relapse as well as predicting if they will benefit from chemotherapy.

The research summary noted lead author Kerr is a consultant and has received research funding from Genomic Health.

Shares Rise

Genomic Health rose as high as 11 percent to $21.00 in extended trading, after closing up 1 cent at $18.91 in Nasdaq Stock Market composite trading prior to release of the report.

The research confirmed that in colon cancer patients taking a new version of the Oncotype DX test, those with a particular 18-gene signature had a 25 percent risk of relapse. People who did not show the same gene pattern had a 10 percent risk that the malignancy would return, the study found.

That information is valuable to doctors who otherwise can’t predict which colon cancer patients will relapse, said Richard Schilsky, president of the cancer organization, in a briefing.

“Twenty percent of cancers recur and we can’t tell who the 20 percent are,” Schilsky said. “It’s a big black box.” The test is “not as powerful as we would like,” he said.

Other Predictive Factors

Schilsky said doctors may want to use this method along with other predictive factors, including a patient’s age, general health, tumor stage, and willingness to get chemotherapy.

The colon cancer gene study, called Quasar, was “a landmark” because it selected patients who should consider chemotherapy after surgery, even though the study failed to meet its second goal of predicting clear benefit from such treatment, said Steven Shak, Genomic Health’s chief medical officer, in a telephone interview.

Shak said the company worked almost four years to identify an 18-gene signature from a bank of tumor samples collected from more than 1,851 patients. Quasar confirmed that the 18-gene test identified recurrence risk in 1,436 patients with stage 2 colon cancer.

Failure to Predict

Use of the gene test failed to predict whether patients would get better using the standard chemotherapy drugs 5-FU and leucovorin, the study abstract concluded.

A separate study previewed yesterday by the oncology society found another genetic test can tell lung cancer patients whether to get chemotherapy or a new drug, according to Schilsky. The research by Masahiro Fukuoka in Japan found that certain gene mutations can inform patients whether their lung cancer will respond best to AstraZeneca Plc’s Iressa or standard chemotherapy drugs carboplatin and paclitaxel.

“Patients showed some striking differences,” said Fukuoka, a professor of medicine at Kinki University School of Medicine in Osaka, Japan, in the telephone briefing yesterday.

In patients who had the gene glitches, Iressa stopped tumor growth for an average 9.5 months, while chemotherapy stopped tumor growth for 6.3 months. In patients with the normal genes, chemotherapy stopped tumor growth for 5.5 months compared with just 1.5 months for Iressa, the study found.

Drug Response Predicted

The study evaluated genes of 437 patients with non-small- cell lung cancer that had spread to their lymph nodes and other body organs. Gene mutations correctly predicted whether they would respond to the drugs, according to the study summary.

Fukuoka has received honoraria from AstraZeneca and other drugmakers, the study said.

Lung cancer is the most lethal malignancy, with an estimated 219,440 new cases and 159,390 deaths in the U.S. in 2009, according to the National Cancer Institute.

While cigarette smoking is the largest risk factor for lung cancer, according to the American Cancer Society, the malignancy can occur in nonsmokers. The Fukuoka study focused on non small- cell lung cancer patients in Asia who had never smoked or were classified as by researchers as “light ex-smokers,” the study abstract said.

Gene Mutations

The gene in question is called EGFr -- for epidermal growth factor receptor. Patients with mutated forms of the gene responded better to Iressa than to chemotherapy, the study said. Chemotherapy worked better in people without the mutations, Schilsky noted.

Drugs like AstraZeneca Plc’s Iressa and Tarceva, by Roche Holding AG’s Genentech unit and OSI Pharmaceuticals, are directed against EGFr, Schilsky said, adding early studies showed only “modest results.” Now that cancer patients can be grouped according to the gene test, candidates for such treatment can be selected according to who will benefit.

“Everybody with non small-cell lung cancer needs to get mutation analysis,” said Schilsky in a May 11 telephone briefing.“If you have lung cancer and your tumor has EGFr mutations, you do far better if you get Iressa,” said Schilsky in the telephone briefing. Patients lacking that glitch, he added, “need to get chemotherapy, which works better in the non-mutated tumors.”

Source : www.bloomberg.com

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