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UI study finds non-invasive, low-cost test for lung cancer is appropriate

IOWA CITY, Iowa -- When it comes to lung cancer diagnosis sometimes less is more, even in the high-tech world of medicine.

That is the message of a University of Iowa study showing that the analysis of sputum -- a low-cost, low-risk method for detecting lung cancer -- makes more sense as an initial diagnostic test for many patients than the more expensive invasive methods. In addition, the potential national savings in testing costs with the adoption of sputum analysis would be at least $30 million per year.

The study conducted by Dr. Stephen Raab, UI associate professor of pathology, is one of the first to compare the cost effectiveness of lung cancer diagnostic techniques such as sputum analysis, bronchoscopy, fine needle aspiration, thoracotomy and expectant management -- following tumor growth with x-rays.

Raab's findings show that the analysis of cells in sputum, the mucus and other material coughed up from the lungs, is an appropriate first-line test for lung cancer in many patients, especially those who have a tumor in the central part of their lung. Compared to other tests, sputum analysis causes little discomfort for the patient, has a low risk for medical complications, is inexpensive and does not adversely affect death rate or life expectancy.

The study concludes that the test should be used more frequently as an initial diagnostic test for lung cancer.

"In this time of cost consciousness, using a sputum cytology first is cheaper for all of society in the long run," Raab says. "But it is also a quality of life question and depends upon the patient. Most people don't want to undergo surgery or other invasive procedures unless it is absolutely necessary. They prefer the sputum test unless they want to know the diagnosis immediately."

According to Raab, sputum analysis was the method most commonly used to diagnose lung cancer before the 1960s. Today, sputum analysis has been virtually replaced by techniques that are more sensitive, but carry a higher risk of medical complications and are more costly.

Though no test is 100 percent effective in detecting cancer, sputum analysis is the least effective, detecting the disease only 40 to 60 percent of the time. Thoracotomy, surgical incision of the chest wall, is the most effective; however, the risk of surgery and the high cost of the procedure and other invasive techniques may tip the scales in favor of the low cost, non-invasive sputum analysis, at least as the initial test for lung cancer. This is particularly true for the majority of lung cancer patients who have advanced cancer and will not benefit from surgery.

The investigators used decision analysis, a sort of diagnostic flow chart, to examine the clinical outcome of various diagnostic tests alone and in combination. A positive result, for any test, indicated the presence of cancer and no further tests were conducted. If no cancer was indicated by the first test, the next test was performed, and so on. Raab and his co-authors examined the effect of the tests on death rate among lung cancer patients, cost of testing, life expectancy and lifetime cost of medical care in patients with centrally- and peripherally-located tumors.

They found that neither life expectancy nor death rate was significantly altered when a sputum analysis was the first diagnostic test performed in patients, particularly those with centrally-located tumors. However, the economic difference was significant when less expensive tests were used to make the diagnosis. For instance, using the sequence of sputum-bronchoscopy-fine needle aspiration and expectant management, initial test and treatment cost was $5,120 as compared to $11,217 for thoracotomy alone. The lifetime cost of medical care was $24,561 for the sputum-bronchoscopy-fine needle aspiration-expectant management series and $33,984 for thoracotomy.

The Surveillance Epidemiology and End Results Program and the National Center for Health Statistics were used to determine life expectancy and death rate.

Test-associated costs were calculated from the billing offices of the UI Hospitals and Clinics and Stanford University Hospital.