Lung cancer can strike almost without warning

The death of ABC News anchor Peter Jennings from lung cancer is a sad reminder of how difficult it is to diagnose and treat the nation's leading cancer killer.

Even though deaths from cancer have been steadily declining since the early 1990s and more Americans are surviving cancer for five years or more, lung cancer remains stubbornly lethal, claiming an estimated 160,440 American lives in 2004, according to the American Lung Institute.

Jennings, who announced to viewers in a hoarse voice four months ago that he had been diagnosed with the disease, had quit smoking 20 years ago, but started up again after the Sept. 11 attacks.

"I was weak and I smoked over 9/11," he said during the evening newscast in April.

Although he visited the ABC News office between treatments of chemotherapy he did not return to the air again. At the time of his announcement, doctors speculated that the noticeable symptoms of hoarseness and weight loss indicated an advanced state of the disease.

Diagnosis often comes too late
There are two major types of lung cancer: non-small cell lung cancer and small cell lung cancer. Non-small cell lung cancer is much more common and usually spreads to different parts of the body more slowly than small cell lung cancer.

The Jennings family has not released specifics about his condition, but no matter which type of lung cancer Jennings had, both are usually caused by smoking or exposure to secondhand smoke. Smoking causes 87 percent of lung cancer cases, studies show. Exposure to radon causes a significant portion of the remaining cases.

Lung cancer, like some other cancers, often doesn’t produce symptoms until it is too late and has spread beyond the chest to the brain, liver or bones.

"Once a person is coughing up blood, it's too late to get a cure," says Dr. Norman Edelman, chief medical officer of the American Lung Association.

The expected 5-year survival rate for all patients in whom lung cancer is diagnosed is 15 percent, compared to 63 percent for colon cancer, 88 percent for breast cancer and 99 percent for prostate cancer, according to the American Lung Association.

Because of late diagnosis, about 6 out of 10 people with lung cancer die within one year of being diagnosed with the disease.

Better detection desperately needed
Why is there no screening for lung cancer that's the equivalent of mammograms for breast cancer, pap smears for cervical cancer or colonoscopies for colon cancer?

The chest X-ray is not considered a very good screening device because studies have shown that even large cancers can hide in a routine X-ray.

Doctors have long sought improved screening tests for lung cancer, but it's only been within the last few years that new developments in technology might make early detection more feasible, says Dr. Steven Keller, chief of the Division of Thoracic Surgery at Montefiore Medical Center in New York City.

The most promising screening tool is computer tomography, or CT images of the lung. More doctors have been using CT scans to find small lung cancer tumors at an early enough stage when surgery is still an option.

A recent study at the New York-Presbyterian Hospital/Weill Cornell Medical Center found that using computerized scans to screen for lung cancer in high-risk patients could help save lives. The researchers recommended using them as part of regular checkups for those at risk.

In the study, researchers followed about 27,000 cases of people who were at a high risk for lung cancer, diagnosing more than 400 with cancer, mostly in the early stages. Of those diagnosed through CT scans who went on to have the cancer removed, 96 percent found that the disease did not return.

Meanwhile, a government study through the National Cancer Institute is following 50,000 people who were assigned to undergo either CT scans or chest X-rays annually for three years. Researchers will track the participants mortality rates through 2009 to determine whether a spiral CT scan is an effective screening tool for lung cancer.

The spiral CT scan is controversial, however, because it is so powerful that it can pick up nodules that may not be cancerous, leading to potentially unnecessary surgeries. And even when the scan picks up smaller tumors, it's possible that the cancer cells have already spread to other parts of the body. Surgery could remove the tumor in the lung, but wouldn't affect parts of the body where the cancer cells have spread.

"The screening predisposes that we have effective treatment that would kill off microscopic tumor cells," says Keller. "But chemotherapy is not at the point where can wipe out whatever tumor cells that have spread elsewhere."

In addition, the tests cost hundreds of dollars and aren't usually covered by insurance.

Does quitting pay off?
But researchers aren't giving up. Studies are looking at alternative detection tools that would analyze chemicals in a patient's sputum and blood, which could indicate the presence of cancer cells. Another method would examine a person's exhaled breath with an "electronic nose" for cells from the lung that might contain cancer DNA.

If Jennings had not started smoking again, would he have still developed the disease? Stopping smoking doesn’t eliminate the risk but it can cut the odds, research shows.

It takes about 10 years to cut the risk for lung cancer, although it never decreases to the level of people who have never smoked, according to the American Cancer Society.

"For the most part, risk is due to cumulative effects of smoking, how many packs multiplied by number of years," although after 20 years of quitting his risk would have declined, says Edelman.

In Jennings case, "he just wasn’t lucky."

Beyond improved detection and treatment, the best way to reduce lung cancer deaths is to convince people not to smoke cigarettes.

"It’s clear that an ounce of prevention here is worth a pound of cure," says Keller. "Without smoking, 90 percent of lung cancer would go away."

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