Abstract
In Proton Medical Research Center, University of Tsukuba, 1,046 patients have been treated from the time of its foundation in September 2001 to March 2007. Our facility focuses mainly on cancers commonly found in Japanese people, such as liver cancer, lung cancer, prostate cancer, esophageal cancer and brain or skull base tumors. Combined with the patients treated in the old facility, approximately 1800 patients have been treated so far in Tsukuba.
In this presentation, I would like to center on our recent trial for malignant gliomas. Glioblastoma, a most malignant type of glioma, is highly radioresistant, harboring mutated p53 in more than half of all cases. In addition, the kinase activity of DNA-PK, a non-homologous end-rejoining enzyme, is found to correlate with their radioresistance. These molecular profiles can partially explain its high radioresistance resulting in very poor outcome of the patients.
We have been treating glioblastoma patients by high dose hyper-fractionated concomitant boost radiotherapy combining x-rays and 200MeV proton beams. In this protocol, 96.4GyE is delivered to the gross tumor volume. So far, 17 cases have been enrolled and their treatments completed.The median survival time of these 17 cases is 21.4 months at present, which is approximately 5 months longer than that of patients treated with 64 Gy of x-ray irradiation in the same institute.
Immunohistochemical analyses of the tissue surgically taken after this treatment were performed in 7 cases. The details of these data will be presented at the meeting.
Our present protocol study is yielding even longer survival in patients with glioblastoma. However, it is mandatory to control peripherally invading tumors using other treatment modalities.
