[Results of electron beam irradiation for tongue cancer]

One hundred and eighty three patients with squamous-cell carcinoma of the tongue were treated with electron beam irradiation at the Dept. of Radiology, Nihon University School of Medicine, from 1967 to 1988. We analyzed the therapeutic results of the investigation to find out indications of squamous-cell carcinoma of the tongue to see if it could be treated by intra-oral cone irradiation with electron beam (IOC). The patients were restaged, as follows: stage I, 38 cases: stage II, 64 cases: stage III, 58 cases: stage IV, 23 cases. There were 113 males and 70 females, ranging in age from 18 to 87 years old. IOC was applied for T 1 or smaller T 2 cases. External neck irradiation and IOC were combined for larger T 2, T 3 or T 4 cases. The two-year local-control rates for primary lesions with the present method were 85% for T 1, 73% for T 2, and 58% for T 3. There were no two-year local-control cases for T 4. Clinical feature of the tumor were classified into tumourous type, small ulcerating type, and large ulcerating type. The two-year local-control rates were as follows: 80% for tumorous types, 68% for small ulcerating types and 53% for large ulcerating types. Uneven fractionated irradiation was performed on 144 cases and even fractionated irradiation was performed on 39 cases. The two-year local-control rates were as follows: 68% for uneven fractionated irradiation cases, 61% for even fractionated irradiation. In T 2 and T 3 cases, the two-year local-control rates were as follows: 77%, 63% for uneven fractionated irradiation cases, 56%, 40% for even fractionated irradiation cases. The two-year local-control rates were increased by uneven fractionated irradiation for T 2, T 3 cases (P < 0.05). We analyzed the therapeutic results in details for T 3 cases. T 3 patients were classified into two categories according to tumor size (category 1: long axis X short axis > 1000mm2: category 2: long axis X short axis < or = 1000mm2). The two-year local-control rates were 48% for category 1, and 72% for category 2. T 3 patients were classified into two categories according to clinical feature of the tumor (tumors with ulcers and tumors without ulcers). The two-year local-control rates were 43% with ulcers, and 74% without ulcers. The actuarial five-year survival rates were 92% for stage I, 72% for stage II, 67% for stage III, and 12% for stage IV.(ABSTRACT TRUNCATED AT 400 WORDS)