GIST Management
Ongoing Management
The poor prognosis for patients with malignant GIST has recently changed with the availability of Glivec® (imatinib), a specific inhibitor of the KIT and PDGFR tyrosine kinases. Glivec is a breakthrough in systemic therapy, achieving unprecedented response rates in clinical trials.1,2 At 52-month follow-up, results of the pivotal phase 2 B2222 trial have demonstrated that 84% of patients with advanced GIST were able to achieve stable disease or better3,4 (16% achieved stable disease, 67% achieved a partial response, and 1% achieved a complete response). The median overall survival with Glivec is 4.8 years
As with all solid tumours, there is a possibility of recurrence or progression of GIST. Frequent monitoring through periodic CT, MRI, or PET scans will ensure that the patient receives the best possible care. Current recommendations published by the European Society of Medical Oncology (ESMO) suggest follow-up with CT scan after primary resection of the GIST tumour on a schedule that corresponds to prognostic risk factors associated with the likelihood of developing malignant GIST disease.
| Patient prognostic risk group (criteria) | Criteria | Monitoring recommendations |
|---|---|---|
| High and intermediate risk | Tumours >5 cm or with mitotic index >5/50 high-power fields | CT scan is recommended every 3 to 4 months for 3 years, then every 6 months until 5 years, and annually thereafter |
| Very low and low risk | Tumours <5 cm and with a mitotic index <5/50 high-power fields | CT scan every 6 months for 5 years is suggested |
For patients with high-risk and intermediate-risk GIST tumours (ie, tumours >5 cm or with mitotic index >5/50 HPFs), a CT scan is recommended every 3 to 4 months for 3 years, then every 6 months until 5 years, and annually thereafter. For patients with very-low-risk or low-risk GIST tumours (ie, tumours <5 cm and with a mitotic index <5/50 HPFs), a CT scan every 6 months for 5 years is suggested.5
Glivec should be given immediately upon diagnosis of unresectable and/or metastatic GIST. Treatment should then be continued until progression, intolerance, or patient refusal6. In the case of progression in GIST, multidisciplinary treatment approaches should be considered including dose escalation of Glivec and clinical trials with Glivec therapy in combination with other agents or targeted therapy agents.5,6
References:
1. Demetri G, von Mehren M, Joensuu H, et al. Long-term clinical outcomes of imatinib treatment in patients with advanced gastrointestinal stromal tumors. J Clin Oncol. Manuscript submitted.
2. Blanke CD, Demetri G, von Mehren M, et al. Long-term follow-up of a phase II randomized trial in advanced gastrointestinal stromal tumor (GIST) patients (pts) treated with imatinib mesylate [abstract]. J Clin Oncol. 2006;24:526s. Abstract 9528.
3. Demetri G, Benjamin R, Blanke CD, et al. NCCN Task Force Report: optimal management of patients with gastrointestinal stromal tumor (GIST)--expansion and update of NCCN Clinical Practice Guidelines. J Natl Compr Canc Netw. 2004;2(suppl 1):S1-S26.
4. DeMatteo RP, Lewis JJ, Leung D, Mudan SS, Woodruff JM, Brennan MF. Two hundred gastrointestinal stromal tumors: recurrence patterns and prognostic factors for survival. Ann Surg. 2000;231:51-58.
5. Blay JY, Bonvalot S, Casali P, et al. Consensus meeting for the management of gastrointestinal stromal tumors. Report of the GIST Consensus Conference of 20-21 March 2004, under the auspices of European Society for Medical Oncology. Ann Oncol. 2005;16:566-578.
6. Reichardt P. Optimising therapy for GIST patients. Eur J Cancer. 2006;4(suppl 1):19-26.