RESEARCH FOR IMPROVEMENT OF LOCAL CONTROL AND LATE EFFECT IN RADIOTHERAPY FOR ORAL CANCERS

1993 Fiscal Year Final Research Report Summary

• Project/Area Number: 04671228
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 外科・放射線系歯学
• Research Institution: HIROSHIMA UNIVERSITY
• Principal Investigator: NAITO Kumiko Hiroshima University, Dental School, Research Associate, 歯学部, 助手 (10155632)
• Co-Investigator(Kenkyū-buntansha): KASHIWADO Kouzo Hiroshima University, Medical Hospital, Research Associate, 医学部, 助手 (70169431) ; HIROKAWA Yutaka Hiroshima University, Medical School, Associate Professor, 医学部, 助教授 (40116653) ; SUEI Yoshikazu Hiroshima University, Dental School, Research Associate, 歯学部, 助手 (10206378) ; KODERA Yoshie Kinki University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (10124794) ; WADA Takuro Hiroshima University, Dental School, Professor, 歯学部, 教授 (10028756)
• Project Period (FY): 1992 – 1993
• Keywords: ORAL CANCER / RADIOTHERAPY / HYPERFRACTIONATION

Research Abstract

Between 1990 and 1993,21 cases of squamous cell carcinoma of the oral region were treated with twice-a-day irradiation (1.2 Gy/fraction, 4-hour interfraction interval), and followings were disclosed.
1.Twice-a-day irradiation with 1.2 Gy/fraction and 4-hour interfraction interval was feasible without a split, even if a total dose was over 80 Gy.
2.The crude survival rate at 2 years was 66.7 % in T1 and 2 cases. Twice-a-day irradiation did not improve the survival rate in T3 and 4 cases, especially in cases with marked mandibular bone destruction.
3.Local control at 2 years was different between stages ; that is, 11/18 in T1 and 2 cases and 3/19 in T3 and 4 cases. This treatment regimen seems to be preferable for T1 and 2 cases in respect of local control but was not sufficient for T3 and 4 cases.
4.Cervical lymph node metastasis was treated in 8 patients, and was controlled in 6. Electron boost was effective for the control of metastasis.
5.Acute mucosal reaction became severer in the 2nd and 3rd radiation weeks. The degree of mucositis was generally less severe and almost all the patients did not need a rest interval during treatment.
6.One pathologic fracture, probably due to toothextraction, was found. There was no interference with the healing process in patients who underwent a salvage operation.
From this study, it was considered that hyperfractionation with a total dose of 80 Gy was preferable for Tl and 2 in respect of local control but was not sufficient for T3 and 4. Combination of chemotherapy to hyperfractionated irradiation might be an another approach to improve treatment results.