Predictive value of quantitative metabolic tumor volume and metabolic index analysis in lung cancer stereotactic radiotherapy with F-18 FDG PET/CT

OBJECTIVE: The objective of this study was to investigate predictive value of quantitative metabolic tumor volume and metabolic index analysis in lung cancer stereotactic radiotherapy with F-18 FDG PET/CT. PATIENTS AND METHODS: Overall, 94 early-stage non-small cell lung cancer (NSCLC) patients who were administered stereotactic radiotherapy were included in the study. RESULTS: Most of the study patients were male (91.5%). Mean age of the patients was 68.5 +/- 9.0 years. The primary lung tumor was located centrally and peripherally in 25 (26.6%) and 69 (73.4%) of the patients, respectively. The median gross tumor volume (GTV) was 16.2 cc [interquartile range (IQR): 7.1-32.9]. Whereas all patients who had peripheral tumors survived. 17 patients with central tumors (70.8%) died during the study period (p= 0.001). Biologically effective dose (BED10) values were significantly higher in patients who had peripheral tumors compared with patients with central tumors (p= 0.001). Significantly more patients died in patients who had BED values below 100 Gy compared to patients who had BED values over 100 Gy (p= 0.001). The survival distributions for the two groups were significantly different (p < 0.001). Only GTV and Pretreatment SUVmean appeared as significant predictors of mortality. BED10 values showed a significant and strong positive correlation with total radiation dose, whereas it showed a significant strong negative correlation with number of fractions. CONCLUSIONS: The use of repeated 18F-FDG PET to assess survival early during stereotactic radiotherapy is possible in patients with early-stage non-small cell lung cancer. A decrease in GTV and pretreatment SUVmean according to F-18 FDG PET/CT uptake by the primary tumor correlates with survival.

Automated summary

This study investigated the predictive value of quantitative metabolic tumor volume and metabolic index analysis in lung cancer stereotactic radiotherapy using F-18 FDG PET/CT. The results showed that a decrease in gross tumor volume (GTV) and pretreatment SUVmean correlated with survival. Patients with peripheral tumors had lower mortality rates and higher BED10 values.