[Clinical, radiological and histopathological studies of squamous cell carcinoma of lower gingiva].

In order to improve the treatment results of the lower gingival carcinoma, the treatment results were analysed based on the X-ray views, histopathological findings and mode of treatment. A series of 152 cases of primary lower gingival carcinomas treated at the First Department of Oral and Maxillofacial Surgery, Tokyo Medical and Dental University, during the 25 years between 1964 and 1988 was surveyed. The lesions with the invasive type of bone resorption on the X-ray picture often had unclear tumor margin histopathologically and those of the pressure type had a smooth front, with a small number of exceptions. The five-year cumulative survival rate was 76.7% for the pressure type, 64.6% for those without bone resorption, 53.9% for the invasive type. The deeper the resorption was, the higher the death rate was in the invasive type. Grade II of WHO classification and Grade 3 of the mode of invasion had the least recurrence rate and the least frequency of delayed cervical metastases. Grade 4D showed the highest recurrence rate and Grade 4C a high frequency of cervical metastases. Five-year cumulative survival rate was 77.8% for the cases treated by surgery, 65.6% for those by the combination of surgery and radiation, 57.1% for those by chemotherapy and 29.5% for those by radiation.