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Study: X-Rays Can Detect Early Lung Cancer


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Study: X-Rays Can Detect Early Lung Cancer


AP Medical Writer

WASHINGTON (AP) -- Use of routine chest X-rays to hunt lung cancer leads to frequent false alarms, but when tumors are found they tend to be early-stage, say preliminary results of the biggest study ever to address lung-cancer screening.

The next question is whether this screening leads to fewer deaths. An answer is still several years away.

More than 172,000 Americans will be diagnosed with lung cancer - the nation's top cancer killer - this year. Most will die within two years because this stealth cancer almost always is diagnosed at advanced stages. If lung tumors are caught early, five-year survival skyrockets, but there is no proven early-screening method.

Studies during the 1970s concluded that X-ray screening didn't save lives, either because it didn't catch the deadliest tumors soon enough or it needlessly put patients with slow-growing tumors through risky surgery and other treatments.

Now, X-rays are being put to the test again in a government-sponsored study of more than 150,000 seemingly healthy 55- to 74-year-olds. Half were given annual chest X-rays; the rest received no screening.

Of the more than 77,000 people screened, doctors spotted something suspicious on the X-rays of 5,991, almost 9 percent, researchers reported Tuesday in the Journal of the National Cancer Institute.

Patients were sent back to their regular doctors for repeat X-rays, CT scans or other evaluations, and 206 wound up undergoing a biopsy.

Ultimately, 126 people were diagnosed with lung cancer - 2 percent of the initially suspicious X-rays.

Importantly, 44 percent of the cancers were in the disease's earliest stage, noted lead researcher Dr. Martin Oken of Minnesota's Hubert H. Humphrey Cancer Center.

But that's a lot of false alarms, cautioned Dr. Christine Berg of the NCI, which is sponsoring the study. So-called false-positive results can bring more than needless anxiety and high health bills; a biopsy sometimes causes a collapsed lung.

The study is tracking the newly diagnosed cancer patients to determine if early detection reduces deaths enough to warrant the false alarms.

"That risk may be worth taking if you knew the lung cancer that could potentially be detected would be caught at an early enough stage to potentially save your life," Berg explained. "But lung cancer is an extremely aggressive disease, unfortunately, and we need to prove that we can have an impact on mortality."

Why revisit X-rays? Partly it's because smokers today tend to get a different form of cancer, called adenocarcinoma, than they did before filtered cigarettes became popular in the 1970s - and modern X-rays might spot those tumors more easily.

Many scientists are betting that a more expensive test, called a spiral CT scan, will prove a better screening tool. A separate government study is under way comparing X-rays with spiral CTs - although the $300 test already is in high demand, as many smokers and former smokers aren't waiting for the evidence.

Lung cancer occasionally strikes people who never smoked. Surprisingly, 14 of the 126 cancer diagnoses in Tuesday's study were among people who had never smoked - and they accounted for more than 40 percent of the initially suspicious screenings.

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A little background information on why we don't screen for lung cancer - which is not to say that we never will, of course.

126 people were diagnosed with lung cancer - 2 percent of the initially suspicious X-rays.

A test with only 2% sensitivity (ability to detect the illness when it is indeed present) is considered extremely poor in medicine.

Also, the article doesn't mention how many of the 98% without lung cancer had biopsy-related complications such as collapsed lung or bleeding. It also doesn't mention the costs of screening in dollars and worry per patient. These are the usual explanations for the lack of routine lung cancer screening.

There is a fundamental dilemma, in my opinion, in making health screening decisions because health policy is necessarily driven by objective data, and what the patient/family experiences (the subjective) is disregarded in the interest of objectivity. However, what the patient experiences is tremendously powerful and health care providers agree that it should be incorporated into the care of people with any kind of disease.

So how do we choose how to spend our limited health care dollars? Objective or subjective data, or both? So far, the choice has been to use the objective data, and those data do not yet support lung cancer screening.

That said, the current study that is still in followup may produce evidence that spiral CT screening does indeed reduce mortality. Stay tuned.

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...and how does a study of "55- to 74-year-olds" do anything for the growing group of young, non-smoking women? Older folks with a history of smoking may have the chest x-ray, along with colonoscopies and mammograms, but that doesn't help us "oddities". One of my college dorm mates is getting over a battle with breast cancer - diagnosed at 35. FAR from "the norm" when screening begins at 40....

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Joel asked for a chest Xray during his physical and they caught the tumor there. Stage 1, had the operation and so far C free.

So to me if it is just a minimal they catch, it still could save lives. It saved his life as he was feeling great and had no signs.


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Tina's point is well taken. The number of people who have the disease but are not detected by the test is called the false negative rate. (I know, more than you may have wanted to know.)

And Rich, glad to provide a little information to all of you.

With best wishes for a healthy and joyful new year, Teresa

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I was thinking about this thread and realized I misspoke - a minor one, but worth correcting.

A test with only 2% sensitivity (ability to detect the illness when it is indeed present) is considered extremely poor in medicine.

This is not entirely right; sensitivity is defined correctly, but the 2% is only the "true positive rate", not sensitivity, because we don't know how many false negatives (people who tested negative but had the diseaes) there were.

Anyway, thanks for the kind wishes, Rich and a wonderful 2006 to all! - Teresa

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