Abstract
Comparative analysis of uptake for 18F-fluorodeoxyglucose (FDG) versus 18F-fluorodeoxythymidine (FLT) PET scans in rectal cancer
Journal of clinical oncology, Vol.32(3_suppl), pp.657-657
01/20/2014
DOI: 10.1200/jco.2014.32.3_suppl.657
Abstract
657
Background: FLT PET is a novel metabolite for imaging cellular proliferation and has shown promise for treatment response monitoring. The utility of FLT PET imaging in rectal adenocarcinomas (RA) has not previously been established. We set out to compare FDG and FLT uptake in RA and correlate FLT response during treatment to tumor regression. Methods: We evaluated 6 patients with RA who were treated on an institutional prospective clinical trial (NCT01717391). Patients were treated neoadjuvantly with concurrent chemoradiation therapy per standard of care. Patients had both FDG and FLT PET scans prior to starting treatment and FLT scans after 1 and 2 weeks of radiotherapy. Tumor volumes and pelvic lymph nodes measuring greater than 6 mm were contoured on the simulation CT scan and adjusted for bladder and rectal filling based on the attenuation correction CT for each PET scan. FLT and FDG SUVs were collected from a total of 40 lymph nodes among the six patients. Pretreatment and change in tumor FLT SUVs were correlated with histopathological regression. The sensitivity of FLT and FDG for identifying lymph nodes was compared using a Student’s t-test. Results: At the time of this analysis, there were post-treatment pathological data on five patients. All but one patient had a decline in the FLT tumor SUV after 2 weeks of treatment. This non-responder was the only patient who did not have histopathological tumor regression after treatment and was the only patient whose pretreatment FLT SUV was below 2. Tumor FDG SUV (4.54 ± 1.03) was consistently higher compared to FLT (2.42 ± 0.51) values, however nodal uptake for FDG (1.89 ± 1.08) was not higher compared to FLT (1.98 ± 0.96). To account for this difference, nodal uptake was normalized to the SUV of each patient’s primary tumor for both FLT and FDG. Mean normalized lymph node FLT SUVs were significantly higher (0.80 ± 0.36) than normalized FDG SUVs (0.44 ± 0.25) (p<0.001). Conclusions: Preliminary data supports using FLT SUV as a biomarker for tumor response early during treatment. Relative FLT uptake in nodal metastasis also appears to be higher when compared to FDG. This indicates potential response and diagnostic applications for FLT PET imaging in RA Clinical trial information: NCT01717391.
Details
- Title: Subtitle
- Comparative analysis of uptake for 18F-fluorodeoxyglucose (FDG) versus 18F-fluorodeoxythymidine (FLT) PET scans in rectal cancer
- Creators
- Arshin Sheybani - University of IowaSudershan Bhatia - University of IowaYusuf Menda - University of IowaLaura Boles-Ponto - University of IowaBrandie Ann Gross - University of Iowa Hospitals and Clinics, Iowa City, IAWilliam Rockey - University of IowaSarah Marie McGuire - University of Iowa Hospitals and Clinics, Iowa City, IA
- Resource Type
- Abstract
- Publication Details
- Journal of clinical oncology, Vol.32(3_suppl), pp.657-657
- DOI
- 10.1200/jco.2014.32.3_suppl.657
- ISSN
- 0732-183X
- eISSN
- 1527-7755
- Language
- English
- Date published
- 01/20/2014
- Academic Unit
- Radiology; Radiation Oncology
- Record Identifier
- 9984315656302771
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