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