Sixty cases of osteoradionecrosis of the mandible were retrospectively studied.
The primary sites of the tumor were 37 tongue, 12 floor of mouth, and 11 oropharynx. The majority of cases in the tongue received radiotherapy combining 60Co external irradiation with 137Cs interstitial irradiation. Most cases of the floor of the mouth and oropharynx received 60Co external irradiation.
The severity of disease was classified as Stage I, II A, II B, III A and II B. There was just 1 case in Stage I which had only bone exposure. In Stage II A there were 19 cases which were cured by sequestration. In Stage III B, 5 cases did not show signs of sequestration and were not cured. In Stage III A, there were 32 cases which healed in spite of pathological fractures and skin fitulae. In Stage III B, there were 3 cases with fractures and skin fistulae in which the disease was not resolved or progressed. Both Stage II and Stage III cases were found in the tongue group and mostly Stage III was noted in the floor of the mouth and oropharynx groups.
As for the initial time of bone exposure, Stage I was 13.0 months, Stage II 14.3 months and Stage III was 22.0 month on the average. All 6 cases showing bone exposure after 48 months were Stage III. Thus the time of bone exposure tended to be later in advanced disease.
Stage I and II received conservative therapy but Stage III was treated surgically. Stage III cases in the tongue group were treated conservatively and the prognosis was relatively good. Stage III cases in the floor of mouth and oropharynx groups showed a poor prognosis when treated conservatively.
The average duration of discomfort was 35 months in all cases. It was found that average duration of discomfort was longer in Stage III cases in the floor of mouth and oropharynx groups than in Stage II cases of the tongue group.