Summary of tumor response assessment and definitions for RECIST, Choi and MASS criteria
| RECIST | MASS | Choi | |
|---|---|---|---|
| Measurements and lesion evaluations | Diameter*1 | Diameter | Diameter |
| CT attenuation (HU) | CT attenuation (HU) | ||
| Marked central necrosis*2 | |||
| Response criteria*3 | ≥30% diameter decrease | ≥20% diameter decrease, ≥40HU decrease, or marked central necrosis | ≥10% diameter decrease, or ≥15% density decrease |
*1: The longest diameters for non-nodal lesions and short axis for nodes were used according to RECIST1.1 [31]. This was applied to size measurement for Choi and MASS criteria in the present study.
*2: Marked central necrosis is defined as >50% of the enhancing central portion of a predominantly solid enhancing mass subjectively changing to near fluid attenuation (necrosis) after treatment [25].
*3: The sum of the diameters of all target lesions and the average of CT density measured in HU are used to assess response, comparing the values on the follow-up scan during therapy in reference to the values on the baseline pretherapy scan.