Targeted versus non targeted lesion measurements – Radiation, RECIST

Please note: lesion = tumor
To measure localized changes:

Targeted: Tumors that have been measured and then compared with follow-up scan

Non-targeted: Tumors that were present and have been noted, but measurements have not been taken

Complete Response (CR): Disappearance of all non-target lesions and normalization of tumor marker level

Incomplete Response – Stable Disease (SD): Persistence of one or more non-target lesion(s) or/and maintenance of tumor marker level above the normal limits

Progressive Disease (PD): Appearance of one or more new lesions and/or unequivocal progression of existing non-target lesions (1)

Radiation technology is still developing and is not perfect. As noted, incomplete response and stable disease are combined. This may take in account the thickness of the CR plate measuring 1 cm and other notable insufficiency inherent to the current technology.