[Analysis of tolerable radiation dose on the oral mucosa and mandibular bone--external beam and/or brachytherapy].

Cooperative study from six institutes was made for the late radiation damage of oral mucosa and mandibular bone. Analysis was made for the selected patients with oropharyngeal cancer for external beam alone and with tongue cancer for interstitial implant. All of them were followed at least two years without recurrence having no secondary treatment after initial radiotherapy. As for external beam alone, frequency of the mucosal ulcer was not increased with high dose level, but tolerance dose for the oral mucosa was limited from associated mandibular damage. Late damages were not likely after brachytherapy alone.