A study on clinical usefulness of nuclear DNA distribution for the judgment of radiotherapy response in oral cancer

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07672174
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: HIROSHIMA UNIVERSITY
• Principal Investigator: TANAKA Kohji Hiroshima University, University Dental Hospital, lecturer, 歯学部附属病院, 講師 (90179747)
• Project Period (FY): 1995 – 1996
• Keywords: oral cancer / radiotherapy / nuclear DNA distribution

Research Abstract

This study was done in order to establish more objective criteria for the judgment of radiotherapy response in oral squamous cell carcinoma. I applied a semiautomatic-scanning microphotometry system connected to a computer with home made analyzing software. During radiotherapy, I measured the nuclear DNA of the exfoliated cells from squamous cell carcinoma in oral cavity of 18 cases and normal oral epithelium of same cases by this system. Measured parameter was the DNA content, the mean DNA density, total measured points of a nuclear region and the nuclear diameter. In addition, I analyzed nuclear DNA distribution with digital image processing and the new parameter "Density Score" was defined from the computing contour lines of DNA density with the computer program originated in this study. It is important to investigate how these parameters changed with increasing dose of irradiation. In 6 cases (33.3%), the Density Score peaked at about 10 Gy irradiation and later showed a decreasing tendency. The Density Score of 7 cases (38.9%) showed decreasing tendency to be similar to normal cells. On the other hand, the Density Score of 3 cases (16.6%) did not changed and that of 2 cases (11.1%) increased in spite of irradiation dose. These cases were poor response cases of radiotherapy. For the judgment of radiotherapy response, it is useful to know how decrease the Density Score.