Bulusu, V. R.;
Jephcott, C. R.;
Fawcett, S.;
Cook, N.;
Hatcher, H.;
Moyle, P.;
Carroll, N.;
Earl, H.;
Save, V.;
Hardwick, R.
RECIST and Choi criteria for response assessment (RA) in patients with inoperable and metastatic gastrointestinal stromal tumours (GISTs) on imatinib mesylate. Cambridge GIST study group experience
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Media type:
E-Article
Title:
RECIST and Choi criteria for response assessment (RA) in patients with inoperable and metastatic gastrointestinal stromal tumours (GISTs) on imatinib mesylate. Cambridge GIST study group experience
Contributor:
Bulusu, V. R.;
Jephcott, C. R.;
Fawcett, S.;
Cook, N.;
Hatcher, H.;
Moyle, P.;
Carroll, N.;
Earl, H.;
Save, V.;
Hardwick, R.
imprint:
American Society of Clinical Oncology (ASCO), 2007
Description:
<jats:p> 10019 </jats:p><jats:p> Background: Imatinib Mesylate (IM) induces an overall response rate of 84% in patients (pts) with metastatic GISTs. Standard RA is by RECIST criteria. This may underestimate the true benefit of IM in such pts. Choi et al observed ↓ in size (10%) and or density (D) (15%) correlated well with disease specific survival. We report our experience using both RECIST and Choi criteria for RA in GIST pts on IM. Methods: Between 2003 and 06, 24 pts with metastatic or inoperable GISTs were treated with IM. 50 lesions (Liver 20, Omentum 21, Primary 9) were identified at presentation on contrast CT (Siemens multi slice CT, IV Niopam, GE PACS system). 3 monthly CT was used for RA until tumour progression (PD) or death. Parameters recorded were: 1.Largest dimension 2. Lesion density (Mean Hounsfield units, HFU) 3.New lesions 4.Any new features. RECIST and Choi criteria were both applied for RA. Results: N=50. At 3 months (m) only 16% of the lesions achieved partial response (PR) by RECIST and 24% increased in size by a mean of 22.5% (Range 3–150%). RA as measured by Choi criteria revealed 88% of lesions had either a 10% ↓ in size or a 15% ↓ in D at 3 m. Mean ↓ in D was 29% (95% CI 24.6–33.4). At 18 m 50% of the lesions achieved PR and 20% had PD by RECIST criteria, and with Choi criteria 68% RR was recorded. Calcification, haemorrhage and perforation within the lesions spuriously altered the mean D value in 15% of the lesions which made assessment by Choi criteria difficult. In 5 pts new hepatic cystic lesions (range 2–22) appeared with a mean D of 16 HF. None were detected in extra-hepatic sites. 4 pts showed new calcifications within lesions 3–18 m on IM. Enhancing nodules within lesions were seen in 4 pts predating clinical PD by 6–18 m. Conclusions: Choi criteria were found to be reproducible in our pts. RRs at 3 months using Choi criteria (88%) were far greater than by RECIST criteria (16%). RRs were more similar at 18 m (68% Choi vs 50% RECIST).Using density for RA can become unreliable in the presence of perforation, calcification and haemorrhage. These criteria should be evaluated by a radiologist experienced in assessing the response to IM in GISTs with awareness of their limitations. </jats:p><jats:p> No significant financial relationships to disclose. </jats:p>