Prognostic value of the quantitative metabolic volumetric measurement on 18F-FDG PET/CT in Stage IV nonsurgical small-cell lung cancer.

RATIONALE AND OBJECTIVES: Stage IV non-small-cell lung cancer (NSCLC) consists of a heterogeneous group of patients with different prognoses. We assessed the prognostic value of baseline whole body tumor burden as measured by metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake values (SUV(max) and SUV(mean)) of all tumors in nonsurgical patients with Stage IV NSCLC.

MATERIALS AND METHODS: Ninety-two consecutive patients with newly diagnosed Stage IV NSCLC who had a pretreatment F-18 fludeoxyglucose positron emission tomography/computed tomography scan were retrospectively reviewed. The MTV, TLG, SUV(mean), and SUV(max) of whole-body (WB) tumors were measured with the MIMvista workstation with manual adjustment.

RESULTS: There was a statistically significant association between overall survival (OS) and ln(MTV)/ln(TLG) at the level of WB tumor burden (MTV(WB)) and of primary tumor (MTV(T)). The hazard ratio (HR) for a 1-unit increase of ln(MTV(WB)) and ln(MTV(T)) before and after adjusting for age and gender was 1.48/1.48 (both P < .001) and 1.25/1.25 (P = .006, .007), respectively. The HR for a 1-unit increase of ln(TLG(WB)) and ln(TLG(T)) before and after adjusting for age and gender was 1.37/1.37 (both P = .001) and 1.19/1.19 (P = .001, .017), respectively. There was no statistically significant association between OS and ln(SUV(max)) and ln(SUV(mean)) at WB tumor burden, primary tumor, nodal metastasis, or distant metastasis (P > .05). There was low interobserver variability between two radiologists with concordance correlation coefficients of 0.90 for ln(MTV(WB)) and greater than 0.90 for SUV(maxWB), SUV(meanWB), and ln(TLG(WB)).

CONCLUSION: Baseline WB metabolic tumor burden, as measured with MTV and TLG, is a prognostic measurement in patients within Stage IV NSCLC with low interobserver variability. This study also suggests pretreatment MTV and TLG measurements may be used to further stratify patients with Stage IV NSCLC and are better prognostic measures than SUV(max) and SUV(mean) measurements.