RESEARCH FOR IMPROVEMENT OF LOCAL CONTROL AND LATE EFFECT IN THE TREATMENT OF ORAL CANCER BY HYPERFRACTIONATED RADIOTHERAPY COMBINED WITH CHEMOTHE|RAFY

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 11671867
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 病態科学系歯学(含放射線系歯学)
• Research Institution: Hiroshima University
• Principal Investigator: FUJITA Minoru Hiroshima University, Dental School, Associate Professor, 歯学部, 助教授 (90116658)
• Co-Investigator(Kenkyū-buntansha): HIROKAWA Yutaka Hiroshima University, Midical School, Associate Professor, 医学部, 助教授 (40116653) ; NAITO Kumiko Hiroshima University, Dental School, Research Associate, 歯学部, 助手 (10155632)
• Project Period (FY): 1999 – 2001
• Keywords: RADIATION THERAPY / HYPERFRACTIONATION / ORAL CANCER / CHEMOTHERAPY / LATE COMPLICATION

Research Abstract

Eighty two patients with previously untreated and biopsy-proven squamous cell carcinoma of the oral cavity were treated by hyperfractionated radiotherapy(HF) with chemotherapy to improve treatment results of radiotherapy. Two-year survival rates of T1 to 4 were 80.4%, 65.5%, 32.7%, and 5.8%, respectively. There was not any findings which improved survival rates by HP alone. However, combined chemotherapy seemed to improve local control rates than HF alone treatment. A higher local control rate was obtained in the patients with lower stages of tumors, and it was considered in the standpoint of organ preservation that a smaller size of buccal carcinoma should be an indication for HF combined with chemotherapy.The results showed followings ; l)The total dose of 80Gy or more was tolerable to patients in the HF alone using a fraction size of 1.2 or 1.4Gy, and 70-74Gy in the HF combined with chemotherapy. 2)Smaller tumors were good candidates for HF with or without chemotherapy, but in larger tumors the goal of HF should be down-staging for a curative operation. 3)Both local and regional controls influenced the survival. 4)Acute reactions in HF alone were torelable to patients, but those in the combined treatment often needed a split of 1-2 weeks. 5)The severest late complication was the mandibular bone necrosis. It was found about 1.5 to 2 years after the treatment. It might be most important to exclude the mandible from an irradiated field as much as possible. This would be accomplished with a computer-simulation system which provide careful treatment planning. Urgent treatment of dental diseases which might be a source of infection should be advisable before radiotherapy. Intensive dental care was necessary not only before radiotherapy but also during and after it. The improvement of this complication should be a breakthrough for further application of HF with and without chemotherapy to oral cancers.