Influence of volumetric 4'-[methyl-11C]-thiothymidine PET/CT parameters for prediction of the clinical outcome of head and neck cancer patients.

Objective: This prospective study compared the value of pretreatment 4'-[methyl-11C]-thiothymidine (11C-4DST) volumetric parameters and those of 2-deoxy-2-[18F] fluoro-D-glucose (18F-FDG) in predicting the clinical outcome in patients with head and neck squamous cell carcinoma (HNSCC).

Methods: Fifty patients with HNSCC underwent 11C-4DST PET/CT and 18F-FDG PET/CT prior to anticancer therapy. 18F-FDG metabolic tumor volume (18F-FDG MTV) and total lesion glycolysis (TLG) were calculated from 18F-FDG PET, and 11C-4DST MTV and total lesion proliferation (TLP) were calculated from 11C-4DST PET. All parameters were measured for the primary lesion and metastatic lymph nodes. Associations between clinical factors and PET/CT parameters and prognostic value were analyzed.

Results: Receiver-operating characteristic analysis revealed that MTV, TLG, and TLP acquired from the primary lesion and metastatic lymph nodes were good parameters for predicting disease relapse and death. The area under the curves (AUCs) ranged from 0.63 to 0.71 for 18F-FDG PET/CT parameters. The AUCs of 11C-4DST PET/CT parameters were larger than those of 18F-FDG (range 0.72-0.81). Univariate analysis revealed that individuals with tumors showing a high value for any PET/CT parameter were at a significantly increased risk of relapse. Upon multivariate analysis, 18F-FDG MTV, 11C-4DST MTV and 11C-4DST TLP were significant independent factors for relapse-free survival (P = 0.04, P = 0.0001 and P = 0.0005, respectively).

Conclusions: Pretreatment 11C-4DST PET/CT volume-based parameters can provide important prognostic information about patients with HNSCC.