Among 309 patients with the squamous cell carcinoma of the oral cavity treated at Department of Oral Surgery, Kyushu University during a period of twenty years, from 1963 to 1983, 11 patients (3.6%) with retromolar cancer were examined with regard to their clinical and histological findings and the causes for poor prognosis
Chief complaints of the patients at the time of the first visit were pain and trismus. Most cases were in advanced condition as nine cases were classified into stage II and IV (4 and 5, respectively). In most instances the lesions were ulcerated and roentgen examination revealed mandibular bone destruction in 4 cases.
Five cases were only treated by radiation and 4 of them died due to recurrence of the primary lesion. One died of other illness.
Six cases in the last five years received surgical treatment combined with preoperative radiation and chemotherapy and another recent case received only surgical treatment. Radical neck dissection was performed on 6 patients and 4 had histologically positive lymph nodes. More than three metastatic lymph nodes were noted over multiple levels in all cases.
Five of the surgically treated cases had primary lesion recurrence and the pterygomandibular region was the most frequent recurrence site. Of 4 fatal cases, two died of primary lesion recurrence and the other two died of lung metastasis and pneumonia, respectively. The crude survival rate in all cases was 37.5% (3/8) for 2 years and 12.5% (1/8) for 3 and 5 years.
This poor prognosis of retromolar cancer patients could be accounted for by the difficulty in control of the primary lesion. Several possible reasons are as follows:
1. Most cases rapidly develop to the advanced stage.
2. It is difficult to determine an exact border of tumor invasion and accordingly difficult to get an adequate surgical margin and exposure.
3. Radiation therapy is less effective on the retromolar cancer.
4. There is difficulty in early detection of recurrence.
