Jaw opening changes after radiotherapy for Nasopharyngeal Carcinoma

Abstract

Objectives: To investigate the changes of jaw opening in patients with nasopharyngeal carcinoma (NPC) after radiotherapy. Methods: Two hundred forty-two consecutive patients with newly diagnosed NPC were recruited. A jaw opening device plus daily jaw exercise instructions was prescribed to each patient. Maximum jaw opening at incisal region was measured at baseline and 2, 6 and 12 after radiotherapy. Multi-way repeated measures ANCOVA test was used to compare jaw opening changes over time and between groups (cancer staging, adjuvant chemotherapy and compliance with the jaw exercise). The level of significance was set to be 0.05.

Results: A total of 212 patients completed the study. There was a significant reduction in mean jaw opening (P<0.05) from baseline (48.5±0.6 mm) to 2 months (46.6±0.6 mm) after radiotherapy. The mean jaw opening was significantly reduced further (P<0.05) at 6 months (42.1±0.7 mm) after radiotherapy but it remained stable at 12 months (42.1±0.8 mm) after treatment. Patients who received adjuvant chemotherapy exhibited significant smaller mean jaw opening after radiotherapy than patients who did not (P<0.05). Cancer staging and compliance with jaw exercise did not affect the jaw opening.

Conclusions: Jaw opening was significantly reduced after radiotherapy for NPC and the use of adjuvant chemotherapy could further compromise the degree of jaw opening.