Role of structures in the masticator space in selecting patients with resectable T4b oral cancer: findings from a survival analysis.

Oral squamous cell cancers involving the masticatory space are staged as unresectable cancers and their treatment is difficult. Curative treatment with extensive surgery followed by adjuvant therapy is one of the treatment options. In this retrospective study, the survival of 123 patients (93 with T4a cancers, 30 with T4b cancers), treated during the period August 2009 to August 2015, was evaluated. The majority had bucco-alveolar cancers (62.6%), were male (61.8%), and were tobacco users (76.4%). The select group of T4b oral cancer patients were treated with surgery, which included infratemporal fossa clearance in all 30 patients, followed by adjuvant therapy. The masseter was the most commonly involved masticatory muscle, and 24 patients had fewer than three involved structures. Free margins were obtained in 90.2% of cases; 41.5% of cases were node-positive. One hundred and four patients (84.6%) completed adjuvant treatment. The median follow-up was 42 months. For node-negative patients with T4a and T4b cancers, the 5-year overall survival was 59% and 50.2%, respectively (P= 0.62), and 5-year disease-free survival was 64.6% and 53.5%, respectively (P= 0.01). In conclusion, the select group of patients with T4b oral cancers and less than three masticatory space structures involved had comparable outcomes to those with T4a cancers after treatment with surgery and adjuvant radiotherapy.