Appendix C. Detail on criteria for audit of the use of imatinib for the treatment of unresectable and/or metastatic gastro-intestinal stromal tumours

Appendix C. Detail on criteria for audit of the use of imatinib for the treatment of unresectable and/or metastatic gastro-intestinal stromal tumours

Possible objectives for an audit

An audit on the appropriateness and effectiveness of use of imatinib for the treatment of unresectable and/or metastatic GIST could be carried out to ensure the following.

  • Imatinib is used appropriately for the treatment of unresectable and/or metastatic GISTs.

  • The use of imatinib for the treatment of unresectable and/or metastatic GISTs is supervised by an appropriate cancer specialist.

Possible patients to be included in the audit

An audit could be carried out on patients diagnosed with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST over a reasonable time period for audit. In view of the small number of patients who may be eligible for inclusion in the audit, all patients should be included in the audit and it may be desirable to collect data for the audit concurrent with treatment.

Measures that could be used as a basis for an audit

The measures that could be used in an audit on the use of imatinib for the treatment of unresectable and/or metastatic GISTs are as follows.

Criterion

Standard

Exception

Definition of terms

1. For a person with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST, imatinib therapy is provided as first-line management as follows:

a. at 400 mg/day and

b. for up to 12 weeks

100% of people with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST

None

2. Imatinib therapy at 400 mg/day is continued beyond the first 12 weeks only if the person's GIST has responded to treatment within 12 weeks 

100% of people with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST who have been provided imatinib

None

'GIST response to treatment' is assessed by imaging to assess the size and density of the tumour(s), patients' symptoms and other factors, and is classified as complete response, partial response or stable disease as defined by the SWOG criteria (see Appendix D).

3. A person whose GIST has responded to imatinib therapy is treated as follows:

a. the person is assessed at intervals of approximately 12 weeks and

b. imatinib therapy at 400 mg/day is continued until the GIST ceases to respond

100% of people with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST who have been provided imatinib and whose GIST has responded to imatinib therapy

None

See above for definition of GIST response to treatment.

'Assessment' includes review of the findings of diagnostic imaging and clinical symptoms.

4. If progressive disease develops in a person whose GIST initially responded to imatinib therapy, the dose of imatinib is not increased

100% of people in whom progressive disease develops when the GIST responded initially to imatinib therapy

A. In cases for which initial tumour flare reaction is possible, either symptoms must persist beyond 4 weeks or there must be additional evidence of progression

B. Lesions that appear to increase in size due to presence of necrotic tissue are not considered to have progressed

See above for definition of progressive disease.

5. A cancer specialist with experience in the management of people with metastatic and/or unresectable GISTs supervises the use of imatinib

100% of people with KIT (CD117)-positive unresectable and/or KIT (CD117)-positive metastatic GIST who have been provided imatinib

None

Clinicians will need to agree locally on what constitutes supervision of the use of imatinib for people with KIT (CD117)-positive unresectable and/or KIT (CD 117) positive metastatic GIST, for audit purposes.

Calculation of compliance

Compliance (%) with each measure described in the table above is calculated as follows.

Number of patients whose care is consistent with the criterion plus number of patients who meet any exception listed

x 100

Number of patients to whom the measure applies

Clinicians should review the findings of measurement, identify whether practice can be improved, agree on a plan to achieve any desired improvement and repeat the measurement of actual practice to confirm that the desired improvement is being achieved.