Medical Edge Newspaper Column

Detecting Lung Cancer Early So Surgery Can Help

Jan. 14, 2007
Dear Mayo Clinic:
We hear about lung cancer prevalence more and more, but we also hear of people surviving with surgery. What types of surgical options are available for lung cancer patients? -- Illinois

Answer:
You are right that lung cancer patients who undergo surgery to remove the cancerous portions of the lung have good survival rates, considerably higher than among those who do not.

But the problem is that relatively few lung cancer patients -- only about 20 percent -- are candidates for surgery, and they are not easy to identify.

Upon diagnosis, the patient's disease is "staged" -- assigned a numerical rating depending on how far it has spread. At one end of the spectrum is Stage I cancer, which means that it has not spread to any lymph nodes or surrounding structures. At the other end, Stage IV, the cancer has spread to other parts of the body, such as the liver, bones or brain. In between are Stage II (spread to neighboring lymph nodes), Stage IIIA (spread from the lung to lymph nodes in the center of the chest), and Stage IIIB (spread locally to areas such as the heart, blood vessels, trachea and esophagus -- all within the chest -- or to lymph nodes near the collarbone or on the other side of the chest).

Stage IIIB and Stage IV patients usually have developed symptoms, such as pain, breathing difficulty, or coughing up blood, that make their disease easier to detect, but by then the cancer has usually advanced too far for surgery to be useful. Most of our surgery patients, then, are at Stages I, II, and IIIA, and the operations are effective. The five-year survival rates are 80 percent, 50 percent, and 30 percent, respectively -- much better than the rate of only about 15 percent for all lung cancer patients.

But patients at these earlier stages are usually symptom-free, with little reason to be tested. Many candidates for lung cancer surgery are in fact discovered accidentally, when an unrelated problem -- persistent back pain, for example -- has prompted their doctor to order an X-ray of the chest area, which then reveals an early-stage lung cancer.

What we need is an inexpensive and accurate screening test comparable to, say, the prostate-specific antigen (PSA) test for prostate cancer. A chest X-ray was thought to be an excellent screening test for lung cancer, but extensive studies have shown that it makes no perceptible overall difference in the lung cancer survival rate -- many of the tumors detected by a simple chest X-ray may be too large and aggressive for subsequent treatment to make much of a difference.

CT scans, a more technologically advanced alternative to chest X-rays, can detect tumors that are smaller and at an earlier stage, so the medical community is hopeful that CT screening will help us find many more Stage I, II, and IIIA patients. But will "smaller" be small enough? The answer is currently being sought through the National Lung Screening Trial -- a major study sponsored by the National Cancer Institute -- that will run through 2009.

Another potential option, still in the laboratory phase, is a chemical test to analyze blood samples for proteins or other molecules that would alert doctors that a patient is at high risk of lung cancer or may already have the disease.

The discussion above applies mostly to non-small-cell lung cancer, as opposed to the more aggressive small-cell type that is caused almost entirely by smoking. Few small-cell patients qualify for surgery because their disease has usually spread throughout their body by the time they are diagnosed.

Of course, the best "treatment" for lung cancer is prevention -- to quit smoking, even if you are a long-time smoker, or, better yet, to not take it up in the first place.

-- Mark S. Allen, M.D., Thoracic Surgery, Mayo Clinic, Rochester, Minn.