Date: 05 Jan 2011

Compliance with PET acquisition protocols for therapeutic monitoring of erlotinib therapy in an international trial for patients with non-small cell lung cancer

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Abstract

Purpose

The Response Evaluation Criteria in Solid Tumors (RECIST) are widely used but have recognized limitations. Molecular imaging assessments, including changes in 18F-deoxyglucose (FDG) or 18F-deoxythymidine (FLT) uptake by positron emission tomography (PET), may provide earlier, more robust evaluation of treatment efficacy.

Methods

A prospective trial evaluated on-treatment changes in FDG and FLT PET imaging among patients with relapsed or recurrent non-small cell lung cancer treated with erlotinib to assess the relationship between PET-evaluated response and clinical outcomes. We describe an audit of compliance with the study imaging charter, to establish the feasibility of achieving methodological consistency in a multicentre setting.

Results

Patients underwent PET scans at baseline and approximately day 14 and day 56 of treatment (n = 73, 66 and 51 studies, and n = 73, 63 and 50 studies for FDG PET and FLT PET, respectively). Blood glucose levels were within the target range for all FDG PET scans. Charter-specified uptake times were achieved in 86% (63/73) and 89% (65/73) of baseline FDG and FLT scans, respectively. On-treatment scans were less consistent: 72% (84/117) and 68% (77/113), respectively, achieved the target of ±5 min of baseline uptake time. However, 96% (112/117) and 94% (106/113) of FDG and FLT PET studies, respectively, were within ±15 min. Bland-Altman analysis of intra-individual hepatic average standardized uptake value (SUVave), to assess reproducibility, showed only a small difference in physiological uptake (−0.006 ± 0.224 in 118 follow-up FDG scans and 0.09 ± 0.81 in 111 follow-up FLT scans).

Conclusion

It is possible to achieve high reproducibility of scan acquisition methodology, provided that strict imaging compliance guidelines are mandated in the study protocol.

Some of this work was presented at the International Association for the Study of Lung Cancer Annual Meeting, San Francisco, CA 2009.