A pilot study of pentoxifylline in the treatment of radiation-induced trismus

Radiation-induced trismus has a significant impact on the quality of life o f patients receiving radiotherapy for head and neck cancers. Pentoxifylline has immunomodulatory activities that downregulate certain cytokines that h ave been implicated as mediators of fibrogenic reactions after radiation. A pilot study was therefore conducted to evaluate the efficacy of pentoxifyl line in the treatment of radiation-induced trismus. Twenty patients with se vere trismus (dental gap less than or equal to 25 mm) after receiving radio therapy for nasopharyngeal carcinoma were enrolled onto the study. Four pat ients were excluded from analysis because of poor drug compliance. The rema ining 16 evaluable patients completed an 8-week course of pentoxifylline at a dose of 400 mg two to three times daily. Changes in dental gap were reco rded by measuring the distance between left upper and lower incisor before and after treatment. At the end of treatment, 10 patients had a measured in crease in dental gap ranging from 2 to 25 mm. Six patients had an increment of 5 mm or more. The mean dental gap before treatment was 12.5 mm compared with 16.5 mm at the end of treatment (p = 0.023). The mean difference in d ental gap was 4 mm, with a 95% confidence interval of 0.6 to 7.4 mm. The dr ug pentoxifylline appears to exert a modest therapeutic effect in patients with radiation-induced trismus, although our findings need to be confirmed by a randomized placebo-controlled study. While awaiting more evidence from clinical studies, a therapeutic trial of pentoxifylline is worth consideri ng in patients experiencing radiation-induced trismus.