Cheek Swab Helps Spot Early Lung Cancer

But experts say the test may not yet be accurate enough for widespread use

MONDAY, Oct. 31, 2005 (HealthDay News) -- One of the reasons lung cancer is so deadly is that it is often detected too late for treatments to be effective.

Now, a new test based on scrapings of inner cheek cells may be useful in identifying early malignancy in high-risk patients, Canadian researchers report.

Using mucosal scrapings from the inner part of the cheek, researchers analyzed changes in the nucleus of those cells to distinguish patients with lung cancer from high-risk patients without malignancy.

The finding could spur more research into the use of cheek cell analysis as a simple, inexpensive method of early detection of lung cancer, the number-one cancer killer of both men and women.

"Ultimately, this test could be administered in primary-care settings or dental offices. The procedure is simple enough that specimen collection could be done by patients themselves," lead researcher Dr. Bojana Turic, the director of clinical and regulatory affairs at Perceptronix, Inc., in Vancouver, explained in a prepared statement.

The findings were to be presented Monday in Montreal at CHEST 2005, the annual international scientific assembly of the American College of Chest Physicians.

"Previous research has shown that cell nuclear changes can extend a significant distance from the site of a malignancy," Turic explained. "We have already conducted a successful clinical trial for our sputum test for lung cancer. New data suggest that the effects of lung cancer can also be measured as far away as skin cells in the mouth."

In their test, Tutic and his team analyzed randomized cheek scrapings of 150 confirmed lung cancer patients and 990 patients at high risk for the disease. "A sufficient amount of cells can be collected by scraping the inside of the cheek with a small wooden spatula similar to a tongue depressor," Turic said.

According to the researchers, the cheek cell test had an overall 66 percent sensitivity -- meaning it spotted cancers two-thirds of the time, and a specificity of 70 percent -- meaning that it had a "false-positive" rate of 30 percent. The test achieved a 61 percent sensitivity when researchers focused on early, stage I lung cancers.

Turic's team cautioned that more testing is needed to validate the test's performance.

Two experts believe this new early detection tool shows promise, but they say it's still not accurate enough to be used in lieu of other diagnostic methods.

"I'm glad to see the work being done," said Dr. Norman Edelman, the chief medical officer of the American Lung Association. "It's a simple, noninvasive, potentially inexpensive test that will pick up early lung cancer. That would certainly be a big help."

However, the test's accuracy in diagnosing stage I lung cancer is only 60 percent, Edelman noted. "That means they will miss 40 percent of cancers. That's hardly a perfect test," he said. "I don't think it's ready for prime time."

"Obviously, we will welcome anything that will aid in the early detection of lung cancer," said Tom Glynn, the director of cancer science and trends at the American Cancer Society. "We're still stuck at about a 15 percent survival rate, and anything that can help improve that obviously is important."

Glynn agreed that the test is still in the early stages of development. "The whole sputum cytology [cell analysis] area has been around for a decade and this study takes it one step further in terms of trying to make it more accurate," he said. "I cannot see this test being universally used until they make it more accurate."

Moe information

For more on lung cancer, head to the American Cancer Society.

SOURCES: Tom Glynn, Ph.D., director, cancer science and trends, American Cancer Society, Washington, D.C.; Norman Edelman, M.D., chief medical officer, American Lung Association, New York City; Oct. 31, 2005, presentation, CHEST 2005, 71st annual international scientific assembly of the American College of Chest Physicians, Montreal, Canada
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