Posttreatment PET may predict survival in lung cancer
Higher tumor uptake of a radiotracer used in positron emission tomography (PET) appears to be a predictor of worse survival in persons who have undergone treatment for stage III non-small cell lung cancer (NSCLC), based on recent study findings.
The American College of Radiology Imaging Network/Radiation Therapy Oncology Group prospective trial, funded by the National Cancer Institute, focused on 250 persons with stage III NSCLC. Mitchell Machtay, MD, chairman of radiation oncology at University Hospitals Case Medical Center and Case Western Reserve University School of Medicine in Cleveland, Ohio, and colleagues hypothesized that the standardized uptake value (SUV) on posttreatment [18F]fluorodeoxyglucose (18F-FDG) PET correlates with survival in stage III NSCLC.
18F-FDG is a radiolabeled glucose molecule. Most cancer cells absorb glucose at a higher rate than do normal cells; 18F-FDG PET can help determine sites of abnormal glucose metabolism and characterize various types of tumors.
As Machtay and fellow researchers explained in Journal of Clinical Oncology (2013;31:3823-3830), the study participants received conventional concurrent platinum-based chemoradiotherapy without surgery. Postradiotherapy consolidation chemotherapy was allowed. A total of 226 patients were evaluable for pretreatment SUV and 173 for posttreatment SUV.
Posttreatment scan was predictive for prognosis, demonstrating that persons with high levels of 18F-FDG uptake following therapy had more aggressive tumors that were more likely to recur, and had worse survival. Pretreatment SUV peak and maximum levels were not associated with survival.
In addition, a strong correlation seen between the radiation dose intensity and local control of the cancer indicated that further research is needed in radiation technology for lung cancer.