Magnetic resonance imaging–based tumor volume measurements predict outcome in patients with squamous cell carcinoma of the mandible

Objective The objectives of this study were to determine the benefit of pretreatment magnetic resonance imaging (MRI)–based tumor volume (Tv) measurements in patients presenting with squamous cell carcinomas (SCCs) involving the oral cavity subsites most frequently associated with mandibular bone invasion. Study Design A 10-year retrospective study of all patients undergoing surgical resection for primary SCC of the retromolar trigone, mandible, or floor of mouth (with bone involvement) was completed. In total, 62 patients met the inclusion criteria, and Tv measurements completed on their pretreatment MRI. Results Tumor volume was significant at predicting all-cause survival and disease-free survival at 5 years. Tv stratification to correlate with the TNM staging system resulted in down-staging in 40 of the 62 cases. Conclusions Tumor volume was a more useful predictor of outcome than the current clinical or pathologic TNM staging, considering the automatic up-staging of tumors involving mandibular bone to T4 tumors.