The relationship between initial radiographic features and prognosis in 38 patients with squamous cell carcinoma of the lower gingiva treated at the Department of Oral and Maxillofacial Surgery at Kyoto University Hospital during the period from 1973 to 1986 was investigated.
Radiographs were first divided into two groups with or without bone resorption. Those showing resorptions were classified according to the mode of resorption as erosive type or invasive type and these were further divided, according to the range of resorption, into those in which the tumor did not extend into the mandibular canal (A range) and those in which it did (13 range).
Kaplan-Meier 5-year survival rates were calculated in each group. 26 (68.4%) of the cases showed bone resorption radiographically, of which 16 (61.5%) were of invasive type and 10 (38.5%) were of erosive type. 18 cases (69.2%) were A range and 8 (30.8%) wereB range. Of the 18 A range radiographs, the number of invasive type was almost equal to that of erosive type, but in B range, the invasive type showed a preponderance. The 5-year survival rate of patients whose initial radiographs showed no bone resorption was 66.7%, while it was 29.8% where radiographs revealed hone resorption.
There was a significant difference (P<0.01) in the 5-year survival rate between patients of invasive type (0%) and those of erosive type (67.5%).
These results suggested that there was a significant relationship between the mode of bone resorption and the clinical course in patients with a squamous cell carcinoma of the lower gingiva.
