Purpose: This prospective study compares the incidence and severity of sensorineural hearing loss (SNHL) in the nasopharyngeal carcinoma patients who received treatment by conventional two-dimensional (2D) radiation to IMRT technique.

Methods and materials: Between November 2009 and August 2010, 18 nasopharyngeal carcinoma patients were treated with chemoradiation (similar to the Intergroup 0099 trial) and randomly assigned to receive radiotherapy by conventional radiation (n=10) and IMRT technique (n=8). Pure-tone audiometries were performed before treatment and on the day that completed radiation to evaluate hearing threshold at low speech (frequencies pure tone average; conversation in normal activities) and high speech frequency (4 kHz). An increase in bone conduction threshold more than 15 dB from baseline was considered as signifi  cant SNHL.

Results:  The incidences of SNHL at PTA were 10% and 12.5% (p=0.608) and at 4 kHz were 15% and 56.2% (p=0.014) for conventional radiation and IMRT group, respectively. There was no difference in the severities of SNHL between two groups at both PTA and 4 kHz (p>0.05).

Conclusion: No signifi  cant difference was seen in the incidence of SNHL at PTA between conventional radiation and IMRT technique. The incidence of SNHL at 4 kHz were signifi  cant greater in IMRT group. The severity of SNHL was also not different between two radiation techniques.