Osteoradionecrosis after the radiation treatment for tongue cancer. The relationship between dental extraction and osteoradionecrosis

Osteoradionecrosis (ORN) generally follows radiotherapy for tongue cancer, and ORN is the most serious clinical problem among these complications. In this study, we focused on the incidence of ORN of the mandible and its relationship with preradiation dental extraction. During the period 1975 through 1990, 124 previously untreated patients with histologically verified squamous cell carcinoma of the tongue were treated by brachytherapy alone or in combination with external radiotherapy. All patients were diagnosed as T1N0, T2N0, according to the TNM classification of UICC, 1979. Twenty-one (18.4%) of 114 tongue cancer patients who underwent radiotherapy without a spacer developed ORN. Nine (20.9%) of 43 and 12 of 71 (16.9%) patients who did and did not undergo preradiation, respectively, developed ORN. The intervals between extraction and radiotherapy for the patients who did and did not develop ORN were 6.9 and 12.4 days, respectively, indicating that at least two weeks should be allowed to elapse after extraction before starting radiotherapy. The patients who underwent preradiation extraction tended to develop ORN earlier than those who did not, and the short interval between extraction and radiotherapy in our institute indicates that an inadequate healing time may increase the risk of ORN in the early postradiotherapy stage. We have used radiation prostheses for 10 patients since 1985, but in this study, their treatment effect was not clear although other workers have already established their usefulness. (author)