Outcome prediction after surgery and chemoradiation of squamous cell carcinoma in the oral cavity, oropharynx, and hypopharynx: use of baseline perfusion CT microcirculatory parameters vs. tumor volume.

PURPOSE: To assess whether pretreatment perfusion computed tomography (PCT) may predict outcome in chemoradiated patients with oral cavity, oropharynx, and hypopharynx squamous cell carcinoma (SCCA) after surgical excision.
MATERIALS AND METHODS: Twenty-one patients with SCCA were examined before treatment. The primary site was oral cavity in 6, oropharynx in 7, and hypopharynx in 8 patients; there were 11 T2, 6 T3, and 4 T4 tumors. PCT was performed at the level of largest tumor diameter based on standard neck CT. The data were processed to obtain blood flow (BF), blood volume (BV), mean transit time (MTT), and permeability surface area product (PS). Regions of interest were free-hand positioned on the lesions to obtain PCT measurements. Tumor volume was also calculated. Follow-up was performed with positron emission tomography (PET)/CT and endoscopy. Pearson correlation coefficient was used for comparison between the subgroups. A regression model was constructed to predict recurrence based on the following predictors: age, gender, tumor (T) and nodal (N) stage, tumor volume, and PCT parameters.
RESULTS: BF(mean), BF(max), BV(mean), BV(max), MTT(mean), PS(mean), and PS(max) were significantly different between patients with and without tumor recurrence (0.0001, p < 0.04). T stage, tumor volume, N stage, BF(max), BV(max), MTT(mean), and radiation dose (p < 0.001) were independent predictors for recurrence. Cox proportional hazards model for tumor recurrence revealed significantly increased risk with high tumor volume (p = 0.00001, relative risk [RR] 7.4), low PS(mean) (p = 0.0001, RR 14.3), and low BF(max) (p = 0.002, RR 5.9).
CONCLUSIONS: Our data suggest that PCT parameters have a prognostic role in patients with SCCA.