悪性腫瘍に対する凍結手術の組織学的研究

抄録

Cryosurgery has now been widely utilized in the treatment of malignant tumors. In spite of many experimental and clinical studies, the true mechanism of cryotherapy remains uncertain yet and the most appropriate modality in cryotherapy is not well established. The present study was performed to try to elucidate the mechanism by light and electron microscopy.
Both transplanted syngeneic mammary adenocarcinoma 755 of C57BL/6 and human squamous cell carcinoma of the head and neck regions were treated.
The degree of the tissue damage was campared in terms of the following four conditions, 1) when the tumors were treated either by freezing alone or freezing-thawing, 2) when the tumors were treated either at -180°C by liguid nitrogen gas or -70°C by nitrogen oxide gas, 3) when the tumors were treated by one- or three- cycled cryosurgery, and 4) when the area of treatment was either limited to the tumor mass or included the surrounding tissues.
The main histological change was the destruction of cell membrane. Cryonecrosis was presumably due to the destruction of cells during thawing subsequent to freezing. It is concluded from our data that to carry out effective cryotherapy, the tumor mass should be treated including wide margin of normal surrounding tissues by three-cycled freezing-thawing at -180°C.