Multi-Threshold Volumetric 18F-FET PET for Tumor Detection and Prognosis in Primary Glioma - A multivariate analysis

Author

Lu Mao

Published

January 29, 2026

Statistical analysis

Unadjusted analysis

Using cutoffs 11.7mL, 2.1mL, 0.6mL, 0.16mL for TBR1.6, TBR2.0, TBR2.5, TBR3.0 respectively, and 2.8 for TBRmax, binary variables are indicating high vs low for each metric. Table 1 shows the results of univariate Cox proportional hazards models for overall survival with each of these binary predictors.

Table 1: Univariate Cox proportional hazards models for overall survival.
Term HR CI Lower CI Upper p-value Predictor
tbr_16 3.59 1.95 6.63 0.0000 tbr_16
tbr_20 4.47 2.17 9.22 0.0000 tbr_20
tbr_25 3.21 1.71 6.01 0.0003 tbr_25
tbr_30 3.07 1.72 5.47 0.0001 tbr_30
tbrmax 2.30 1.18 4.47 0.0143 tbrmax

Adjusted analyses

Adjusting for age, sex, tumor_type, days_surgery_to_fet, dayssincescan1, and cycles, Table 2 shows the results of multivariate Cox proportional hazards models for overall survival with each of these binary predictors.

  • the HRs are reduced after adjustment.
Table 2: Multivariate Cox proportional hazards models for overall survival adjusting for clinical covariates.
term estimate conf.low conf.high p.value predictor
tbr_16 1.353931 0.6342545 2.890209 0.4335262 tbr_16
tbr_20 1.887150 0.7641938 4.660251 0.1685466 tbr_20
tbr_25 1.351465 0.5963085 3.062942 0.4706029 tbr_25
tbr_30 1.566375 0.7705579 3.184096 0.2150277 tbr_30
tbrmax 1.296668 0.5575515 3.015590 0.5463014 tbrmax

Table 3 shows the results of multivariate Cox proportional hazards models for overall survival adjusting for TBRmax. Each of TBR1.6, TBR2.0, TBR2.5, and TBR3.0 is adjusted for TBRmax in separate models.

  • The HRs remain strong and significant after adjusting for TBRmax, indicating that these volumetric metrics provide prognostic information beyond TBRmax alone.
Table 3: Multivariate Cox proportional hazards models for overall survival adjusting for TBRmax.
term estimate conf.low conf.high p.value predictor
tbr_16 3.690522 1.667351 8.168618 0.0012770 tbr_16
tbr_20 5.586598 2.190132 14.250316 0.0003172 tbr_20
tbr_25 5.599095 1.340175 23.392355 0.0182094 tbr_25
tbr_30 3.186174 1.337498 7.590071 0.0088815 tbr_30