Prediction of distant metastasis and survival in adenoid cystic carcinoma using quantitative 18 F-FDG PET/CT measurements.

OBJECTIVES: Adenoid cystic carcinoma (AdCC) in the salivary gland shows a high rate of distant metastasis, which is related to the resulting poor prognosis. We therefore examined the role of pretreatment 18 F-FDG PET/CT for prediction of distant metastasis, recurrence/progression, and survival in AdCC.

METHODS: This study included 52 patients who underwent pretreatment 18 F-FDG PET/CT scanning and subsequent treatments for AdCC. Maximum, mean, and peak standardized uptake value (SUVmax , SUVmean , and SUVpeak ), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured on 18 F-FDG PET/CT. Univariate and multivariate Cox proportional hazards regression analyses were used to identify associations between the quantitative measurements of 18 F-FDG PET, and progression-free survival (PFS), distant metastasis-free survival (DMFS), and disease-specific survival (DSS).

RESULTS: Distant metastases were found in 20 (39%) patients: 6 (12%) at initial diagnosis and 14 (27%) during the median follow-up of 72 months after treatment. Univariate analyses showed that all the 18 F-FDG PET parameters of SUVmax , SUVmean , SUVpeak , MTV, and TLG were significantly associated with overall PFS, DMFS, and OS (all P < .05). After controlling for clinicopathological variables, SUVmax remained an independent factor predictive of PFS (P = .001), while MTV and TLG were independent predictors of DMFS (P = .009) and DSS (P = .017). Patients with MTV > 14.8 mL showed a 5.9-fold higher risk of distant metastasis and a 4.2-fold higher risk of disease-specific death than those with a lower MTV.

CONCLUSIONS: Quantitative measurements using 18 F-FDG PET/CT are useful for predicting tumor progression, distant metastasis, and survival in patients with AdCC.