Intensity-modulated radiotherapy for stage I glottic cancer: a short-term outcomes compared with three-dimensional conformal radiotherapy

Purpose: To investigate the differences in treatment outcomes between two radiation techniques, intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and Methods: We retrospectively analyzed 160 (IMRT = 23, 3DCRT = 137) patients with stage I glottic cancer treated from January 2005 through December 2016. The IMRT was performed with TomoTherapy (16 patients), volumetric-modulated arc therapy (6 patients), and step-and-shoot technique (1 patient), respectively. The 3DCRT was performed with bilateral parallel opposing fields. The median follow-up duration was 30 months (range, 31 to 42 months) in the IMRT group and 65 months (range, 20 to 143 months) in the 3DCRT group. Results: The 5-year overall survival and 3-year local control rates of the 160 patients were 95.7% and 91.4%, respectively. There was no significant difference in 3-year local control rates between the IMRT and 3DCRT groups (94.4% vs. 91.0%; p = 0.587). Thirteen of 137 patients in the 3DCRT group had recurrences. In the IMRT group, one patient had a recurrence at the true vocal cord. Patients treated with IMRT had less grade 2 skin reaction than the 3DCRT group, but this had no statistical significance (4.3% vs. 21.2%; p = 0.080). Conclusion: IMRT had comparable outcomes with 3DCRT, and a trend of less acute skin reaction in stage I glottic cancer patients.