ABSTRACT
Cryosurgery is a method of in situ destruction of tumors using subfreezing temperatures (<−20°to −30°C). Intraoperative
ultrasonography is utilized for accurate placement of cryoprobes and precise monitoring
of the freeze front. This allows the application of cryosurgery to treatment of deep
liver tumors, since the visible freeze front can be monitored in real time to ensure
complete ablation of tumor sites with extension of the cryolesion beyond the tumor
margins into the adjacent surrounding liver. The morbidity from the procedure is fairly
low and primarily involves bleeding at the cryosurgical site from cracks in the liver
capsule. Length of stay is on average 2 to 3 days less for cryosurgical ablation than
for hepatic resection. Actuarial survival curves at 3 and 5 years show comparability
to published surgical survival curves. It should be noted, however, that there is
no evidence of plateau in the survival curve, even at 5 years; hence, further long-term
follow-up studies are necessary. Surgical resection remains the definitive treatment
for liver cancer, but most patients are technically unresectable. A certain percentage
of these patients may benefit from cryosurgical ablation, which allows for sparing
more liver parenchyma. The precise role of cryosurgical ablation relative to other
therapeutic modalities, such as percutaneous ablative techniques, hepatic artery chemo
embolization, and newer techniques such as gene therapy, will require much further
study.
KEYWORDS:
Liver, interventional procedure - liver neoplasms, therapy - liver neoplasms, ultrasound
- ultrasound, intraoperative - cryotherapy
