Development of Percutaneous Cryosurgery for Renal Tumor

1991 Fiscal Year Final Research Report Summary

• Project/Area Number: 01570901
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Urology
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: UCHIDA Mutsumi Kyoto Prefectural University of Medicine, Urology, Assistant Professor, 医学部, 講師 (70168706)
• Co-Investigator(Kenkyū-buntansha): KAWAUCHI Akihiro Kyoto Prefectural University of Medicine, Urology, Clinical Conductor, 医学部, 助手 ; IMAIDE Yoichiroh Kyoto Prefectural University of Medicine, Urology, Clinical Conductor, 医学部, 助手 (90203306)
• Project Period (FY): 1989 – 1991
• Keywords: Renal tumor / Cryosurgery / Percutaneous surgery

Research Abstract

Recently, as many doctors think much of the "quality of life" in the treatment of patients, many minimal invasive surgical methods have been developed. However, treatment for the renal tumor is mainly by open surgery. Though chemotherapy, interferon and the embolization of the renal artery have been used, the effective rates are not high. It seemed important to investigate the use of percutaneous cryosurgery for renal tumor using interventional ultrasound.
At first, an original cryoprobe was developed in order to carry out the puncture. This probe was only 6.8m in diameter and the tip of the probe was 30mm. The possibility of percutaneous cryosurgery for renal tumors was examined using this probe.
In freezing tests of renal cell cancer cell lines, most were necrosed after freezing below -20ﾟC, through many survived after freezing above -10ﾟC. This result suggested that the freezing temperature for renal cell cancer must be below -20ﾟC.
In freezing tests of the human kidney, though human r enal cell cancer could be frozen by the original probe, the freezing temperature with irrigation was different from that without irrigation. Without irrigation, the freezing temperature reached -20ﾟC which was necessary temperature to necrose renal cell cancer. However the freezing temperature with irrigation did not reach -20ﾟC. This result suggested that in the treatment of hypervascular tumors the embolization of the renal artery was necessary as a pretreatment.
The monitoring of cryosurgery is important in order to minimize the damage to the normal tissues. We tried to monitor cryosurgery for renal tumors. As a result, in all instances of freezing a freezing iceball could be seen as a hypoechoic lesion with partial hyperechoic rim drawing an acoustic shadow. This result suggested that sonography is an effective means of monitoring cryosurgery for renal tumors.
Percutaneous puncture with the cryoprobe is necessary to place the probe in the middle of the tumor. We have experience of performing biopsy of renal tumors using interventional ultrasound, and are able to reach the aimed position with accuracy.
Percutaneous cryosurgery is a promising treatment for renal tumors. Clinical evaluation will be undertaken in the near future.