
<b>Cryoablation of Tumors  [Often liver.]</b>

Cryoablation [sometimes called cryosurgery] is done with a machine which uses pressurized argon and helium gases to regulate freezing and thawing processes. There is scanning during placement of the probe.  Once the probe is activated, freezing and thawing cycles are monitored with MRI. Multiple cycles are performed to obliterate as much of the tumor as possible. 

Freezing tumor cells interrupts critical cell functions and results in cell death. Cells that remain within the body are absorbed along with scar tissue. The effectiveness of cryotherapy has been well documented as it is utilized in the treatment of numerous lesions throughout the body. Freezing and thawing cycles have been well studied; they are not experimental in nature.

The procedure is performed under general anesthesia. After freezing, the probe is removed and the incision is closed with two or three sutures. Recovery time ranges from two to eight days, depending on the location of the lesion and depth of treatment. You will need pain medication.

Risks of the procedures include freezing of non-target tissues, internal bleeding, infection and damage to normal structures in the vicinity of the target tumor.  [From FAQs of next section]

"The technological advances which have caused renewed interest in cryosurgery are the development of intraoperative ultrasound to monitor the therapeutic process and the development of new cryosurgical equipment designed to use supercooled liquid nitrogen. The thin, highly efficient probes, available in several sizes, can be placed in diseased sites via endoscopy or percutaneously in minimally invasive procedures. The manner of use is to place the probe in the desired location in the diseased tissue with ultrasound guidance. If required by the size or location of the tumor, as many as five probes can be inserted and cooled to -195 degrees C simultaneously. The process of freezing is monitored by ultrasound which displays a hypoechoic (dark) image when the tissue if frozen. Rapid freezing, slow thawing, and repetition of the freeze/thaw cycle are standard features of technique." [1]
"The cases selected for cryosurgery are generally those for which no conventional treatment is possible.  ... Diverse tumors [in sites] such as the brain, bronchus, bone, pancreas, kidney, and uterus, have ... been treated in small numbers by cryosurgery. Judging from this experience, further expansion in the use of cryosurgical techniques seems certain." [1] 

1. Cryobiology 1997 Jun;34(4):373-84
Minimally invasive cryosurgery--technological advances. 
Baust J, Gage AA, Ma H, Zhang CM. 
Center for Cryobiological Research State University of New York, Binghamton 13902, USA. 
&&url PMID: 9200822

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