Comparison of PET/CT with F18-FDG and with C11-choline for the detection of recurrence of head and neck cancer after radio-chemotherapy

Objectives FDG avid inflammatory reaction after combined radio-chemotherapy has disturbed early detection of recurrence using PET. Here we have examined the possibility of C11-choline PET for post radio-chemotherapy evaluation of advanced head and neck cancer. Also optimal timing to perform PET/CT after radiotherapy was explored.

Methods Sixty subjects (40 men and 20 women) with inoperable head and neck cancer (31-77 y.o., mean 58) were recruited. PET/CT imaging with C11-choline and with F18-FDG were performed to all the patients in the same day in this order between 8 -10 weeks after the radio-chemotherapy. The PET/CT imaging was evaluated with visual interpretation. All the patients were followed for one year after PET/CT and checked the recurrence with a biopsy and other imaging in 3 times: within 3 months and between 3 and 6 months, and 6 months and 12 months.

Results The recurrence after PET/CT was eventually conformed in the 20, 5 and 4 patients each term. The sensitivity and specificity of F18 FDG-PET at 3 months after therapy (90.5% and 89.7%, respectively) and of C11 choline PET (87.5% and 79.5%) were higher than those at 6 months (FDG:73.1% and 88.2%, choline:69.2% and 76.5%) and 12 months (FDG:64.5% and 89.6%, choline:61.3% and 75.9%).

Conclusions For the detection of recurrent head and neck cancer after chemo-radio therapy, the ability of the C11 coline PET/CT was not superior to F18 FDG PET/CT. F18 FDG-PET/CT at 3 and 6 months after therapy may be the best timing for the initial and second follow-up PET/CT.