Metabolic active tumour volume quantified on [F-18]FDG PET/CT further stratifies TNM stage IV non-small cell lung cancer patients

Purpose This study aimed to assess whether the whole body metabolic active tumour volume (MTVWB), quantified on staging [F-18]FDG PET/CT, could further stratify stage IV non-small cell lung cancer (NSCLC) patients. Methods A group of 160 stage IV NSCLC patients, submitted to staging [F-18]FDG PET/CT between July 2010 and May 2020, were retrospectively evaluated. MTVWB was quantified. Univariate and multivariate Cox regressions were carried out to assess correlation with overall survival (OS). C-statistic was used to test predictive power. Kaplan-Meier survival curves with Log-Rank tests were performed to compute statistical differences between strata from dichotomized variables and to calculate the estimated mean survival times (EMST). Survival rates at 1 and 5 years were calculated. Results MTVWB was a statistically significant predictor of OS on univariate (p < 0.0001) and multivariate analyses (p < 0.0001). The multivariate model with MTVWB (Cindex +/- SE = 0.657 +/- 0.024) worked significantly better as an OS predictor than the cTNM model (Cindex +/- SE = 0.544 +/- 0.028) (p = 0.003). An EMST of 29.207 +/- 3.627(95% CI 22.099-36.316) months and an EMST of 10.904 +/- 1.171(95% CI 8.609-13.199) months (Log-Rank p < 0.0001) were determined for patients with MTVWB < 104.3 and MTVWB >= 104.3, respectively. In subsamples of stage IVA (cut-off point = 114.5) and IVB patients (cut-off point = 191.1), statistically significant differences between EMST were also reported, with p-values of 0.0001 and 0.0002, respectively. In both substages and in the entire cohort, patients with MTVWB >= cut-off points had lower EMST and survival rates. Conclusion Baseline MTVWB, measured on staging [F-18]FDG PET/CT, further stratifies stage IV NSCLC patients. This parameter is an independent predictor of OS and provides valuable prognostic information over the 8th edition of cTNM staging.

Automated summary

This study found that baseline MTVWB, measured on staging [F-18]FDG PET/CT, further stratifies stage IV NSCLC patients. It is an independent predictor of OS and provides valuable prognostic information. Patients with higher MTVWB have lower EMST and survival rates.