The use of PET with the F-18-fluorothymidine (F-18-FLT) can help predict the early early loco-regional outcomes of chemoradiotherapy for patients with head and neck cancer, according to a study in the October issue of the Journal of Nuclear Medicine.
According to the authors, led by Hiroshi Hoshikawa, M.D., of Kagawa University in Japan, while studies have shown that F-18-fluorodeoxyglucose (F-18-FDG) PET may be used to assess response, it has been associated with false-positives. The research team decided to compare the utility of F-18-FDG with that of F-18-FLT.
In the study, 28 patients with head and neck squamous cell carcinomas underwent both F-18-FLT and F-18-FDG PET imaging before radiation therapy, four weeks after radiation therapy began, and again five weeks after it was completed. Uptake of both agents was measured in primary and metastatic lesions.
The researchers found that during radiation therapy F-18-FLT uptake decreased more significantly than that of F-18-FDG. F-18-FLT accumulations disappeared in 34 of 54 lesions and had a negative predictive value of 97 percent. F-18-FDG PET also had a high negative predictive value of 100 percent but only 16 percent of the lesions showed an absence of F-18-FDG.
F-18-FLT's specificity and accuracy were "significantly higher" than that of F-18-FDG during and after radiation therapy, the authors reported. According to a release by the Society of Nuclear Medicine and Molecular Imaging, "this indicates that F-18-FLT PET is more useful for assessing early loco-regional clinical outcomes and helpful for avoiding unnecessary radical surgery,"
"With the development of new molecular imaging agents, it's now up to clinical researchers to utilize them to assess the characteristics of malignant tumors and their therapeutic response to chemotherapy, radiotherapy and molecular targeting therapy," said Hoshikawa in the release. "We hope that our findings will be helpful in understanding the significance of F-18-FLT-PET."