Pretreatment PET Metabolic Tumor Volume Is Associated With Outcome in Stage III NSCLC
In a study reported in the Journal of the National Cancer Institute, Ohri et al found that higher pretreatment metabolic tumor volume on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was associated with poorer overall survival and an increased risk of locoregional failure in patients with locally advanced non–small cell lung cancer (NSCLC) receiving definitive concurrent platinum-based chemoradiotherapy.
Study Details
The study was a secondary analysis in the ACRIN 6668/RTOG 0235 study, which evaluated the prognostic value of FDG-PET uptake before and after treatment in the patient population. Complete data were available for 214 patients in the overall survival analysis and 189 patients in the locoregional control analysis.
Effect of Baseline Metabolic Tumor Volume
On multivariate analysis including PET metrics and clinical variables (sex, age, performance status, and clinical stage), pretreatment metabolic tumor volume was an independent predictor of worse overall survival, with a hazard ratio of 1.04 per 10 cm3 increase (P < .001). High metabolic tumor volume was also associated with an increased risk of locoregional failure at baseline (HR = 1.16 per 10 cm3 increase, P < .001); the risk decreased over time and was significant at 6 months (HR = 1.05 per 10 cm3 increase, P < .001) but not at ≥ 12 months.
Other independent predictors of overall survival were age (P = .01) and performance status (P < .001), and performance status was also a significant predictor of locoregional failure (P = .006). FDG-PET maximum standardized uptake value was not significantly associated with overall survival (P = .64) or locoregional control (P = .65).
The investigators concluded: “Pretreatment [metabolic tumor volume] is a predictor of clinical outcomes for NSCLC patients treated with chemoradiotherapy. Quantitative PET measures may serve as stratification factors in clinical trials for this patient population and may help guide novel trial designs.”
Nitin Ohri, MD, of Montefiore Medical Center, Albert Einstein College of Medicine, is the corresponding author of the Journal of the National Cancer Institute article.
The study was supported by the Radiological Society of North America Research & Education Foundation, American College of Radiology Imaging Network (now the Eastern Cooperative Oncology Group-American College of Radiology Imaging Network Cancer Research Group), and National Cancer Institute.
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