Abstract
Background3’-Deoxy-3’-[18F]fluorothymidine ([18F]FLT) PET has limited utility in abdominal imaging due to high physiological hepatic uptake of a tracer. We evaluated [18F]FLT-PET/CT combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (KSF) to improve tumour visualisation in patients with locally advanced and metastatic gastro-oesophageal cancer and as a marker of early response to chemotherapy.Dynamic [18F]FLT-PET/CT data were collected before and 3 weeks post first cycle of chemotherapy. Changes in tumour [18F]FLT-PET/CT variables were determined. Response was determined on contrast-enhanced CT after three cycles of therapy using RECIST 1.1.ResultsTen patients were included. Following application of the KSF, visual distinction of all oesophageal and/or gastric tumours was observed in [18F]FLT-PET images. Among the nine patients available for response evaluation (RECIST 1.1), three patients had responded (partial response) and six patients were non-responders (stable disease). There was a significant association between Ki-67 and all baseline [18F]FLT-PET parameters. Area under the curve (AUC) from 0 to 1 min was associated with treatment response.ConclusionsThe results of this study indicate that application of the KSF allowed accurate visualisation of both primary and metastatic lesions following imaging with the proliferation marker, [18F]FLT-PET/CT. However, [18F]FLT-PET uptake parameters did not correlate with response. Instead, we observe significant changes in tracer delivery following chemotherapy suggesting that further [18F]FLT-PET/CT studies in this tumour type should be undertaken with caution.
Highlights
Chemotherapy is the mainstay of therapy for patients both with locally advanced and metastatic gastrooesophageal cancers (GOCs) [1, 2]
As [18F]FLT is a biomarker of cellular proliferation, we investigated the relationship between Ki-67, a histologic marker of proliferation with the PET variables SUVmean and SUVmax
The kinetic spatial filtering (KSF) has been investigated by our group in visualising pancreatic cancer, and liver metastases from different primary tumour sites, and we have consistently demonstrated the applicability of this technique [17, 18]
Summary
Chemotherapy is the mainstay of therapy for patients both with locally advanced and metastatic gastrooesophageal cancers (GOCs) [1, 2]. In patients with locally advanced disease, the aim of neoadjuvant chemotherapy is to downstage the tumour to enable complete surgical resection, whilst in the metastatic setting, the overall goal is palliation. In both clinical scenarios, accurate and sensitive evaluation of tumour response is critical as combination chemotherapy is not without significant side-effects. There is a need for early assessment of tumour response to minimise patient exposure to potentially toxic treatment regimens, especially in those patients unlikely to benefit. The MUNICON I trial conducted in patients with tumours of the oesophagogastric junction illustrated that early metabolic response assessment with [18F]fluorodeoxyglucose ([18F]FDG-PET) guides therapy allocation following 2 weeks of therapy [3]. There is a need to develop more specific tracers for both predicting and monitoring efficacy of chemotherapy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
