Cryosurgery with "Argon-Helium Knife"

Cryosurgery With “Argon-Helium Knife”

Cryosurgery is a novel technique for treatment of cancer which is approved by FDA,USA,1998 and SFDA, China, 1999. Our Hospital has used the technique since 2000, has theexperience of about 4000 patients with a variety of malignant tumors (more 34 kinds ofcancers), stands first on the list in China and over world.

• Principle

Cryosurgery is an important ablation technique for tumor. It destroys tumors by freezing andthawing them. Cryosurgery destructive effects on tumors are due to two major mechanisms,one immediate, the other delayed. The immediate mechanism is the damaging effect offreezing and thawing the cells. The delayed mechanism is the progressive failure ofmicrocirculation; ultimately, vascular stasis becomes operative as an important cause oftumor tissue destruction.Once the temperature falls below -40˚C, ice crystals may form within the cells. Once itoccurs, cell death is almost certain.During cryosurgery, progressive failure of microcirculation occurs due to a cascade of events:endothelial layer destruction causing vessel walls to become porous, interstitial edema,platelet aggregation, microthrombii, and ultimately vascular congestion and obliteration.It was theorized that during cryosurgery, the immune system of the host becamesensitized to the tumor being destroyed by the cryosurgery. Any primary tumor tissueundamaged by the cryosurgery and the metastases were destroyed by the immunesystem after cryosurgery. This response was termed the “cryoimmunological response.”

• Procedure Of Cryosurgery

Cryosurgery is performed through intraoperative, endoscopic or percutaneous routesdepending upon the location and size of tumor.Cryoablation was performed by using argon-helium system (Endocare, CA, USA). Two tothree cycles of the freezing/thawing were performed. The freezing continued until the iceballwas large enough to cover tumor. A 5-10 mm margin of normal tissue was included inthe freezing process. For larger tumors, multiple cryoprobes were used. In some cases, itbecame necessary to perform at least 2-3 sessions of the cryoablation procedure.

• Advantages

1. Cryosurgery is a localized medical procedure. It can be used as the sole means ofcancer treatment or it can be combined with other conventional treatment techniquessuch as surgical operation, chemotherapy, radiotherapy.
2. Combining cryosurgery with excision can be advantageoussince freezing the tumor before excision minimizes the risk ofspreading the cancerous cells during excision
3. In addition to sparing healthy tissue, cryosurgery is advantageousbecause it is not dose-limited， can be repeated asnecessary in order to destroy all cancerous tissue
4. In situations where the tumor is not removed after freezing,especially percutaneous cryosurgery, operative blood loss issmall and post-surgical discomfort is minimized
5. Cryoprobes are relatively small (generally in the range of 24mm in diameter) and therefore they may be used in minimallyin-vasive surgical procedures
6. There are no major side effects which are commonly found inchemotherapy or radiotherapy
7. Cryosurgery is adaptable for treatment of tumor close to largevessel which cannot be removed by operation
8. Cryosurgery can treat small as well as large tumors, and solitaryas well as multiple tumors
9. Cryosurgery per se aims at a local effect, namely, destructionin situ of neoplasms resistant to conventional treatments, butit also elicits an immunologic reaction (cryoimmunologic reaction)against cancer for eradication of residual or metastatictumors
10. There is evidence that the recurrence rate of cancer aftercryosurgery is lower than that of operation

• Indication

Nearly all parenchymal cancers can be given cryoablation.These malignancies include:

• Liver cancer
• Lung cancer
• Kidney cancer
• Ovary cancer
• Pharyngeal cancer
• Testicular cancer
• Uterine tumors
• Vaginal cancer
• Pancreatic cancer
• Breast cancer
• Sarcoma and other benign or malignantlesions of bone
• Prostate cancer
• Skin cancer and melanoma
• Head and neck cancer
• Malignant or benign tumors of soft tissues

In addition, cryosurgery can be an effective treatment for the following:

• Retinoblastoma (a childhood cancer that affects the retina of the eye)
• Early-stage skin cancers (both basal cell and squamous cell carcinomas)
• Precancerous skin growths known as actinic keratosis
• Precancerous conditions of the cervix known as cervical intraepithelial neoplasia (abnormalcell changes in the cervix that can develop into cervical cancer)