Functional imaging: Predicting patient outcomes during chemo-radiation therapy for NSCLC? (#105)
Positron emission tomography (PET)/computed tomography (CT), using 2′-deoxy-2′-[18F]fluoro-d-glucose (FDG) is the best available imaging modality for diagnosing and staging non-small cell lung cancer (NSCLC). In patients proceeding with radiation therapy (RT), FDG PET/CT also facilitates superior identification of target lesions for RT. However, in routine clinical practice, the radiobiological response of NSCLC is unknown throughout the six week course of therapy.
This presentation will discuss a clinical trial that was initiated to study the interim anatomical and biological tumour response of NSCLC in candidates for radical chemo-RT. Seven sequential PET/CT scans using FDG and a novel PET radiopharmaceutical 3′-[18F]fluoro-3′-deoxy-l-thymidine (FLT) were used to assess the metabolic (FDG) and proliferative (FLT) tumour response. Both a FDG and FLT PET/CT scan was performed prior to the commencement of therapy and during the second and fourth weeks of therapy. A FDG PET/CT was also performed following treatment completion.
Between 2009-13, 60 patients participated in the study, yielding approximately 400 PET/CT scans for analysis. Preliminary results suggest that functional imaging with FDG and FLT provides an early insight into the biological tumour response to chemo-RT. Further, a comparison of equivalent time-point scans reveal an earlier response on FLT PET, with many tumours demonstrating no FLT uptake at week four. Although the design of the study was observational, clinically significant findings prompted changes to the management of several patients. This included the detection of brain metastases on baseline FLT PET/CT and progressive local, regional and distant disease detected during the course of chemo-RT on FDG and FLT PET/CT study scans.
This presentation will provide an overview of the metabolic and proliferative therapeutic response of NSCLC to chemo-RT as observed by sequential FDG and FLT PET/CT imaging. The ability of these scans to predict patient outcomes and potential strategies for future biologically personalised treatments based on interim imaging will also be discussed.