Impact of postoperative daily image-guided intensity-modulated radiotherapy on overall and local progression-free survival in patients with oral cavity cancer

Background: We compared the outcome of patients who received non-image-guided intensity-modulated radiotherapy (IMRT) with those who received helical tomotherapy (HT), a daily image-guided radiotherapy (IGRT), after surgery for oral cavity cancer (OCC). Methods: During the period November 2006 to December 2013, a total of 152 postoperative OCC patients underwent either IMRT (n = 79) or daily IGRT (n = 73) 4 to 6 weeks after surgery. Patients in the IMRT group received 6 MV photon beams to 7 fields and those in the IGRT group received daily fractions of 1.8 or 2 Gy on five consecutive days. Results: Patients who received daily IGRT had higher 5-year overall survival than those who received IMRT (87 % versus 48 %, p = 0.015). The local progression-free survival rate was also higher in patients who received IGRT (85 % versus 58 %, p = 0.006). More patients in the IGRT group completed the package of overall treatment time in ? 13 weeks and completed their course of radiation therapy in ? 8 weeks than patients in the IMRT group (89 % versus 68 %, p = 0.002; 84 % versus 58 %, p = 0.001), respectively. The rate of local failure in the primary tumor area was 24.0 % in the IMRT group and 6.8 % in the IGRT group. Among patients with primary local failure, the marginal failure rate was 52.6 % in the IMRT group and 0 % in the IGRT group. Conclusions: For patients with locally advanced OCC, postoperative IGRT results in better overall survival, better local progression-free survival, less marginal failure and shorter overall treatment time than postoperative non-image-guided IMRT. ? 2016 Hsieh et al.