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

2004 Fiscal Year Final Research Report Summary

• Project/Area Number: 14571787
• 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, Graduate School of Biomedical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (90116658)
• Co-Investigator(Kenkyū-buntansha): NAITO Kumiko Hiroshima University, Graduate School of Biomedical Sciences, Research Associate, 大学院・医歯薬学総合研究科, 助手 (10155632) ; LEE Kaoru Hiroshima University, Hospital, Research Associate, 病院・助手 (00294596)
• Project Period (FY): 2002 – 2004
• Keywords: RADIOTHERAPY / HYPERFRACTIONATION / ORAL CANCER / CHEMOTHERAPY

Research Abstract

Ninety two patients with previously untreated and biopsy-proven squamous cell carcinoma of the oral cavity were treated by hyperfractionated radiotherapy (HF) with or without chemotherapy (CT) to improve treatment results. Ultimate local control rates of all patients were 44.8%. This fairly good result was considered to be contributed by the number of T2 tumors among them. There was not any improvement in local control rates by HF alone with a fraction size of 1.2Gy compared with standard radiotherapy by conventional fractionation. Neoajuvant CT seemed to improve local control rates slightly than HF alone treatment. A higher local control rate was obtained in the patients treated by HF concomitantly with CT. Similar local control rate was obtained by HF alone with a fraction size of 1.4Gy, and the use of neoadjuvant CT combined to HF with a fraction size of 1.4Gy showed a higher local control rate. These results suggested that a larger fraction size might provide a higher local control rate and that CT combined with HF might also provide a better local control rate, even if CT was combined neoajuvantly or concomitantly. CT concomitantly combined with HF, however, provided a higher local control rate obviously. The results suggested followings ; 1)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 CT. 2)Smaller tumors were good candidates for HF with or without CT, but in larger tumors the goal of HF should be down-staging for a curative operation. 3)The severest late complication was the mandibular bone necrosis. Although it might be most important to exclude the mandible from an irradiated field as much as possible, it is inevitable to exclude the mandible in the treatment of oral cancer. Intensive dental care should be necessary not only before HF but also during and after it. The improvement of this complication should be a breakthrough for further application of HF with and without CT to oral cancers.