Figure 1. Hypothetical Tumor Volume Variation and Definition of Hyperprogressive Disease (HPD) in the Immunotherapy Cohort.

Variation of tumor growth rate (TGR) volume per month was calculated both before the start of programmed cell death (PD-1) and programmed cell death ligand 1 (PD-L1) inhibitor therapy and during PD-1/PD-L1 inhibitor therapy. Hyperprogressive disease was defined as Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 progressive disease at the first computed tomography (CT) scan during PD-1/PD-L1 inhibitor therapy and an absolute increase in the TGR exceeding 50% per month.
^aNew lesions and nonmeasurable disease not included in the TGR.
^bThe baseline CT scan performed within 6 weeks before PD-1/PD-L1 inhibitor therapy initiation.