[Radiation-induced temporomandibular joint damage in nasopharyngeal carcinoma patients after intensity-modulated radiotherapy].

Background & Objective: Radiation-induced temporomandibular joint damage is a kind of common complication after radiotherapy for nasopharyngeal carcinoma (NPC) patients. Trimus is the main symptom of this damage, and severely affects the quality of life of the patients. This study was to evaluate radiation-induced temporomandibular joint damage in NPC patients treated with intensity-modulated radiotherapy (IMRT), and analyze its affecting factors.

Methods: From Feb. 2001 to Feb. 2003, 148 naive NPC patients were treated with IMRT by 2.27-2.80 Gy per fraction at a total dose of 63-77 Gy within 31-86 days. The distance between 2 dens incisivus medialis (DDIM) was measured before radiotherapy, and 6 months, 1 year, 2 years, and 3 years after radiotherapy, respectively.

Results: The overall 1-, 2-, and 3-year survival rates were 97.26%, 94.83%, and 92.04%. The irradiation dose to temporomandibular joint was 17.9-51.36 Gy. Seven (4.73%) patients suffered from grade I-II temporomandibular joint damage after IMRT; no patient had grade III-IV temporomandibular joint damage.

Conclusions: IMRT can spare the temporomandibular joint from high dose irradiation. The risk of radiation-induced severe temporomandibular joint damage in NPC patients after IMRT is low.