Page 200 - 18F-FDG PET as biomarker in aggressive lymphoma; technical and clinical validation

Chapter 7
used to assess the effect on EOT response rate and the survival endpoints of the following baseline characteristics: BM involvement, WHO PS categorized as 0, 1, 2 or 3, disease stage I-II versus III-IV, presence of B symptoms, presence of concomitant diseases, IPI, number of extranodal localizations categorized as 0, 1, 2 or more, and age as continuous variable. The predictive value of CMR at interim response evaluation for CMR at EOT was assessed through positive predictive value (PPV ) and negative predictive value (NPV ), where response was simplified to “CMR” versus “no-CMR”. PPV was defined as the proportion of patients without EOT PET-CT CMR among the patients without CMR on iPET, and NPV was defined as the proportion of patients with EOT PET-CT CMR among the patients with CMR on iPET. The effect of CMR at EOT on OS was independently evaluated using achievement of CMR as a time-dependent covariate in a Cox proportional hazards regression model, and visualized using the Kaplan-Meier method with a landmark at 7 months.
Exploratory analyses consisted of descriptive subgroup analyses based on rearrangement group (SH versus DH and TH) as determined by central pathology review. Analyses were performed by tabulation of response rate and Kaplan-Meier curves for OS by rearrangement group. All analyses, except analysis of the primary endpoint for which R software was used, were performed using Stata software, version 15. Data cut-off was June 28, 2019.
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