PET/CT predicts chemo response in lung cancer patients

FDG-PET/CT can accurately tell which lung cancer patients will have a successful response to chemotherapy, and therefore a longer survival, and which will not, according to a study in the May issue of the Journal of Nuclear Medicine. Findings may have important implications for patient management.

Chemotherapy, alone or combined with radiotherapy, remains the standard of care for patients with inoperable non-small cell lung cancer. Chemo does not work in every case, however, subjecting some patients to unnecessary toxicity and severe side effects. The ability to provide an early indication of therapeutic response could improve patient care by identifying those patients who are not benefiting from their current treatment, said principal investigator Dr. Claude Nahmias, a professor of radiology and medicine at the University of Tennessee Medical Center in Knoxville.

"Although we studied a relatively small number of patients, it is clear that a repeat PET study with FDG at the end of the first cycle of chemotherapy would allow the identification of those patients for whom the therapy was futile," he said.

Nahmias and colleagues prospectively assessed 16 patients with non-small cell lung cancer as they received two courses of treatment with docetaxel and carboplatin. Patients underwent weekly FDG-PET/CT scanning over seven weeks, starting right before the first chemo dose. The investigators found that PET/CT scans performed at one and at three weeks accurately indicated which patients would successfully respond to treatment.

Fifteen patients completed the study. Eight did not respond and died within 35 weeks after the completion of the study. Seven patients were classified as responders. Five survived, while one died at 25 weeks and another at 76 weeks. A 0.5 decrease in FDG standardized uptake value at one and three weeks scanning correlated with survival longer than six months.

By the end of the first cycle of chemotherapy, FDG-PET/CT would allow identification of patients who will not benefit from the treatment. These patients could benefit by either stopping chemo or by entering a different, more adequate therapeutic approach, Nahmias said.

The small patient sample calls for caution in interpreting results. This study needs validation by a larger trial, but it demonstrates that patients who respond to chemotherapy and those who do not can be identified early in the course of their treatment, Nahmias said.

"I am forever grateful to all the patients who came back week after week to undergo our PET scans," he said.

For more information from the Diagnostic Imaging archives:

PET/CT finds footing in breast, cervical, and ovarian carcinoma

Experts pinpoint benefits of hybrid systems in cancer

Oncology tasks require disease-specific PET/CT

Imagers explores PET/CT for lung cancer diagnosis