Purpose: The aim of this study was to determine if the standardized uptake value (SUV) of fluorodeoxyglucose positron emission tomography (FDG-PET) for head and neck cancer can predict the outcome of radiotherapy and if the SUV is correlated with histological grade, mitosis, and apoptosis.
Materials and methods: The study included 45 head and neck cancer patients who underwent FDG-PET scanning before radiotherapy. The maximum SUV (SUVmax) of their primary lesions were measured. Biopsy was performed in all patients to determine the histological diagnosis. Altogether, 14 biopsy specimens were available for mitotic and apoptotic cell counts.
Results: The mean SUVmax of T3 tumors was significantly higher than that of T1 (P = 0.01) and T2 (P = 0.011) tumors. The mean SUVmax of stage II disease was significantly lower than that of stage III (P = 0.028) and stage IV (P = 0.007) disease. There was a tendency toward a better locoregional control rate and disease-free survival for the lower SUV group using a cutoff value of 5.5. For 41 patients with squamous cell carcinoma or undifferentiated carcinoma, SUVmax did not reflect the histological grade. There was no correlation between the SUVmax and the mitotic/apoptotic status.
Conclusion: SUVmax may correlate with the T classification and stage, but there was no predictive value for outcome of radiation therapy. Neither histological grading nor mitotic/apoptotic status is correlated with SUVmax.