From Stanford University Medical Center
Stanford study determines cost-effectiveness of lung cancer diagnostic tools STANFORD, Calif. - A promising imaging system called FDG-PET is a cost-effective way to diagnose lung cancer if used selectively, said researchers at the Stanford University Medical Center and Veterans Affairs Palo Alto Health Care System. The team investigated a number of diagnostic methods and found that the cost-effectiveness of each approach depends critically on a patient's risk of malignancy.
FDG-PET, which stands for positron emission tomography with 18-fluorodeoxyglucoseis, is an imaging test that can identify malignant tumors on the basis of their increased metabolic rate. Although expensive, the test has become increasingly popular in evaluating single nodules, or spots on the lung, that could be cancerous.
"FDG-PET is very helpful an in almost all circumstances can provide useful information and improve outcomes," said Michael Gould, MD, lead author of a paper appearing in the May 6 issue of the Annals of Internal Medicine. "It's an expensive test, but we found it can be a very good value when it's used selectively."
More than 150,000 single lung nodules are discovered in patients each year in the United States. Most of the small, round or egg-shaped lesions are discovered incidentally on chest X-rays; about 60 percent of all nodules are benign. If a patient is diagnosed with lung cancer - the leading cause of cancer death among men and women in the United States and other developed countries - the only cure is the removal of the tumor before it spreads.
Gould said management of lung nodules can be challenging because clinicians and patients must take into account the risks and benefits of each approach. In addition to FDG-PET, other diagnostic and management tools for lung cancer include computed tomography, or CT, an inexpensive test that provides cross-sectional images of the body and is commonly used to evaluate a nodule; needle biopsy; surgery (considered the diagnostic "gold standard"); and "watchful waiting," in which chest X-rays or CT scans are repeated every several months.
Each approach has disadvantages, said Gould. FDG-PET is more expensive than CT but not 100 percent accurate; CT does not reliably distinguish between malignant and benign nodules; biopsy is potentially risky and does not always reveal presence of cancer; surgery is not recommended for patients with benign lesions; and watchful waiting could delay diagnosis and treatment in cases of malignancy.
"For every month you wait and observe, the cancer could be growing," said Gould, an assistant professor of medicine at the School of Medicine. "The cancer could be curable in the beginning but then wind up spreading." Gould's study aimed to quantify the health effects and economic costs associated with each approach.
The researchers first used literature review and meta-analysis to estimate the accuracy and complications of each diagnostic tool. They then studied survival outcome from a large tumor registry and Medicare claims data to estimate long-term outcomes and costs associated with the approaches. The team went on to conduct separate cost-effectiveness analyses for populations of patients with low, intermediate and high risks of malignancy.
The results were expressed in terms of costs, quality-adjusted life-years and incremental cost-effectiveness ratios. The researchers found that FDG-PET is highly effective for lung nodule diagnosis, but is most cost-effective when CT results and the risk of cancer conflict with one another, for example when CT results indicate a possible malignancy in a low-risk patient or, less commonly, when CT suggests a benign diagnosis in a high-risk patient. Such an approach ensures that FDG-PET is used in cases in which the diagnosis is most in doubt.
Among the team's other findings:
- It is cost-effective to use CT as the initial test in nearly all patients with lung nodules.
- Because strategies that use FDG-PET are more costly and only marginally more effective than CT-based strategies in this population, it is not cost-effective to use FDG-PET when the risk of cancer is intermediate.
- For patients who are not at high risk of surgical complications, strategies that use surgery and needle biopsy aggressively result in slightly better outcomes and slightly higher costs than less aggressive strategies.
- Watchful waiting without any other testing is the least expensive strategy for patients in all risk categories, but it is much less effective than other management approaches.
Gould recommends that clinicians rely on CT as the initial test for almost all patients and use FDG-PET selectively. "As clinicians, our obligations are to our patients, but we also have an obligation to use resources wisely," said Gould, who is now studying the cost-effectiveness of FDG-PET for lymph node staging. "By using expensive technology unnecessarily we're not fulfilling that responsibility."
Gould's collaborators on the study include Gillian D. Sanders, PhD, assistant professor of medicine; Paul G. Barnett, PhD, consulting associate professor of health research and policy; Chara E. Rydzak, former research assistant; Courtney C. Maclean, former research assistant; Mark B. McClellan, MD, PhD, associate professor of economics and of medicine; and Douglas K. Owens, MD, associate professor of medicine. The research was funded by a Career Development Award from the Department of Veterans Affairs' Health Services Research and Development Service and the VA Cooperative Studies Program.
Stanford University Medical Center integrates research, medical education and patient care at its three institutions - Stanford University School of Medicine, Stanford Hospital & Clinics and Lucile Packard Children's Hospital at Stanford. For more information, please visit the Web site of the medical center's Office of Communication & Public Affairs at http://mednews.stanford.edu.
PRINT MEDIA CONTACTS: Michelle Brandt at 650-723-02372 (firstname.lastname@example.org) and Amy Adams at 650-723-3900 (email@example.com)
BROADCAST MEDIA CONTACT: Neale Mulligan at 650-724-2454 (firstname.lastname@example.org)