The Therapeutic Benefit of Radical Resection for T4b Oral Cavity Squamous Cell Carcinoma with Partial or Complete Response After Radical Chemo-Intensity-Modulated Radiotherapy (IMRT)

Background: This study investigated the therapeutic benefit of radical resection (SRR) for clinical T4b oral cavity squamous cell carcinoma (OSCC) with partial or complete response after radical chemoradiotherapy (CRT). Methods: At the authors’ institution, 79 patients with newly diagnosed non-metastatic T4b OSCC were treated with CRT from January 2009 to December 2014. All of them were irradiated using intensity-modulated radiotherapy (IMRT), with a radical dose (median 70 Gy; range 66–76 Gy) in the gross tumor area. Of the 65 cases achieving partial or complete response after CRT, 33 were treated further with SRR and 32 with adjuvant chemotherapy or observation. The locoregional control (LRC), overall survival (OS), and cancer-free survival (CFS) rates were compared between the two groups. Results: The 3-year LRC, OS, and CFS rates were respectively 72.3, 75.1, and 72.6 % in the SRR group compared with 32.8, 47.7, and 44.3 % in the non-SRR group (p < 0.05). Multivariate analysis showed that SRR was the only statistically significant prognostic factor related to LRC, OS, and CFS. For those with SRR, pathologic downstaging was observed in 27 cases (81.8 %). Perioperative flap failure was observed in three cases (9.2 %) and neck wound necrosis in four cases (12.1 %). Conclusions: For T4b OSCC, incorporating SRR in the therapy is technically safe and has survival benefit, with a significant response after CRT applied by IMRT, with a radical dose in the gross tumor area.