PET scans aid in diagnosis of non-small-cell lung cancer patients

PET scanning is much more accurate in determining how far lung cancer has spread than any other diagnostic technique, and should be the standard of care, according to an Australian research team.

In their study, the use of PET scans to double check a diagnosis made by traditional CT and bone scan tests resulted in altered treatment plans in 67 percent of 105 patients with non-small-cell lung cancer.

Because PET is an imaging technique that looks at function instead of structure, it can detect cells that are actively growing, such as tumor tissue. In the study, PET scans revealed cancer in 27 patients that had spread farther than thought based on other conventional imaging modalities. This more accurate staging "spared a substantial number of patients the morbidity related to futile attempts at aggressive therapy," said study co-author, Rodney Hicks, MD, of the Peter MacCallum Cancer Institute in East Melbourne.

But in 10 of 16 patients for whom only palliative therapy was planned because their cancer was diagnosed as too far advanced, PET imaging revealed that their cancer was treatable. PET thus "offered a chance of survival in a significant number of patients who would have been denied potentially curative therapy based on false-positive imaging studies," Hicks said.

Results of a PET scan also changed the extent of radiation treatment that 22 patients ultimately received, and 12 patients originally considered to have inoperable lung cancer underwent surgery as a result of their PET results.

Dr. Hicks said PET results which led to changes in treatment appeared to offer the correct diagnosis in all but one patient, and he believes the technique should routinely be added to CT as a diagnostic tool for staging lung cancer if therapy is being planned. While he said that many health care providers say PET scans are too expensive, Hicks maintains the cost is offset by improved selection of treatments for patients.

"Clinical Impact of 18F Fluorodeoxyglucose Positron Emission Tomography in Patients with Non-Small-Cell Lung Cancer: A Prospective Study;" R. Hicks, et al.; Peter MacCallum Cancer Institute, Melbourne, Australia. Vol. 19, No. 1, (January) 2001, pp. 111-118.