In a presentation on October 2011 at the 2011 annual meeting of the American Society for Radiation Oncology (ASTRO) in Miami Beach (FL, USA), Mitchell Machtay, MD, lead investigator of the ACRIN 6668/RTOG [Radiation Oncology Therapy Group] 0235 trial and RTOG deputy chair, reported that posttreatment F-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging scans show promise for predicting the prognosis of patients with inoperable disease. “These results are encouraging,” said Dr. Machtay. “Definitive prognostic information after a patient completes therapy has not been available for making decisions about further treatment options, and these preliminary results suggest that FDG-PET may play an important role in that regard.”

Twenty American College of Radiology Imaging Network (ACRIN; Reston, VA, USA) and RTOG participating sites enrolled 251 patients into the phase III trial that gathered pre- and posttreatment FDG-PET scans—treatments, which included both chemotherapy and radiation therapy. Specifically, investigators sought to determine if the standardized uptake value (SUV), a quantitative measure of how rapidly tumor cells are using the glucose-based FDG radiotracer, obtained on posttreatment FDG-PET scans was predictive of a patient’s survival. As Dr. Machtay reported, “The posttreatment scan was predictive for patients’ prognosis by identifying that patients with high levels of FDG uptake following treatment had more aggressive tumors that were more likely to recur, and the higher the SUV measure in the primary tumor, the greater the recurrence rate and the lower a patient’s corresponding survival outlook.”

“The results suggest that FDG-PET has a role in helping physicians make more informed treatment decisions, such as starting a patient on a new chemotherapy program,” stated Barry Siegel, MD, ACRIN codeputy chair and medical director of the ACR PET Imaging Core Laboratory, “and helping investigators determine whether a treatment regimen is worthy of further study before long-term survival data are available.”

The FDG-PET scan findings provided for this analysis were interpreted by physicians at the participating sites. Further analyses are ongoing evaluating scan data interpreted by central review at the ACR Imaging Core Laboratory and using other semiquantitative measures.

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American College of Radiology Imaging Network