Criteria of therapeutic response

LD measured on liver metastasis

Evaluation of treatment response in oncology is one of the basic parameters not only for clinical studies, but also for determining the clinical success of treatment. In practice, for example, it can decide to change Palliative care.

RECIST criteria, are currently used for solid tumors , previously used WHO criteria are considered obsolete. .

Evaluated lesions

RECIST focuses on so-called „measurable lesions“, which are lesions with the longest dimension (LD) ≥20 mm or ≥10 mm when using spiral CT. Although all changes that have occurred in a patient need to be assessed clinically, the RECIST classification, unlike the WHO classification, does not evaluate other features (so-called "evaluable lesions"), such as ascites or peritoneal spread.

„Non-measurable lesions“ are all other lesions observable on imaging methods that do not meet the criteria for measurable lesions.

RECIST criteria

The determination of the overall therapeutic response consists of the evaluation of measurable lesions and non-measurable lesions.

Measurable lesions

Objective response is assessed in 4 stages according to changes in LD in long-term target lesions:

1. Complete response (CR) – disappearance of all target lesions.
2. Partial response (PR) – at least a 30% decrease in the sum of the longest averages (LD) compared to the initial measurement.
3. Stable disease (SD) – failure to meet the conditions for CR, PR or PD.
4. Progressive disease (PD) – at least a 20% increase in the sum of the longest averages (LD) or the appearance of 1 or more new lesions.

Non-measurable lesions

CR for immeasurable lesions is their complete disappearance and normalization of tumor markers. The progression of the disease (PD) is determined by the unambiguous progression of existing lesions or the emergence of new lesions. Conditions that do not meet these criteria are referred to as SD.

Overall response

According to the RECIST criteria, we determine the overall answer as follows:

• Complete remission (CR)
  • CR in measurable and non-measurable lesions.
• Partial remission (PR)
  • CR in measurable and SD in non-measurable lesions;
  • PR for measurable and CR / SD for non-measurable lesions.
• Disease stabilization (SD)
  • SD for measurable and CR / SD for non-measurable lesions.
• Disease progression (PD)
  • PD in any criterion.

iRECIST

Due to the emergence of immunotherapy modified criteria were introduced. These include the phenomenon of pseudoprogressionthat arises from successful immunotherapy. Thus, the disease will not be evaluated as a progressive and thus functioning immune therapy

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• ws:Kritéria léčebné odpovědi