Prognostic value of masticatory muscle involvement in nasopharyngeal carcinoma patients treated with intensity-modulated radiation therapy

MM involvement is an independent prognostic factor for OS and LRFS. We conclude that the decision to down-stage MP as T2 in the 8th edition staging system is valid. However, tumors with LP involvement were more rational classified into a higher T-staging category than tumors with only-MP involvement.