Cryosurgery
Cryosurgery is a medical procedure that employs extreme cold to treat various conditions, primarily focusing on the removal of minor skin lesions, such as warts and freckles, as well as certain types of skin and internal cancers. Utilizing liquid nitrogen as its primary cryogenic agent, cryosurgery is valued for its low cost and the ability to perform the procedure in outpatient settings, such as dermatology or family practice offices. The procedure works by freezing tissue, which disrupts cell membranes and leads to cell death, followed by tissue regeneration within weeks.
Cryosurgery is particularly effective for superficial skin cancers, such as basal and squamous cell carcinomas, with high cure rates reported, especially in facial areas where scarring is minimal. It is also applied in the treatment of internal cancers, including prostate, liver, and pancreatic cancers, often used in conjunction with other treatments to enhance outcomes. While cryosurgery generally results in less pain and shorter recovery times compared to traditional surgery, it may lead to side effects such as discoloration, minor scarring, and, in some cases, complications like incontinence. As the field continues to evolve, the long-term effectiveness of cryosurgery for certain cancers remains an area of ongoing research.
Cryosurgery
Also known as: Cryotherapy
Anatomy or system affected: All
Definition: The destruction of undesired or abnormal body tissues by exposure to extreme cold.
Indications and Procedures
Cryosurgery, the therapeutic use of extreme cold, is used to remove minor skin lesions, such as freckles and warts, as well as cancers of the skin and other tissues. Skin heals well after cold injury, and skin pathologies were among the first lesions treated cryosurgically. Although cryosurgery is not the first treatment choice for all skin problems, it is a popular one because of the availability of liquid nitrogen, the main cryogenic agent. In addition, cryosurgery is inexpensive compared to other procedures and can be performed without surgical facilities. For example, family physicians and dermatologists use it to treat minor skin lesions at their offices.
Cryosurgery kills tissue via extracellular and intracellular ice. When cells freeze, extracellular ice squeezes them together and changes their extracellular/intracellular volumes. Thawing causes similar, opposite changes that break cell membranes. The rapid temperature drops used in cryosurgery produce intracellular ice, another major source of cell destruction. The result is altered solute concentrations in tissue fluid, electrolyte loss from cells, disrupted membranes, and protein inactivation and transmigration. Reversed temperature gradients cause more destruction during thawing.
Cryosurgery results in tissue hyperemia, discoloration, and ice buildup. On thawing, edema (swelling) develops, yielding necrosis (cell death) in four days. Dead tissue sloughs off in three more days. Within a month, it is replaced by granulation tissue, which yields normal tissue.
Cryosurgery uses between one and five freeze-thaw cycles (FTCs). The freeze speed is 300 degrees Celsius per minute with a drop from 37 degrees Celsius to -196 degrees Celsius followed by crash (about ten-second), short (one-minute), medium (about three-minute), or long (ten-minute) thaws, depending on the type of lesion treated.
For external tissue treatment, liquid nitrogen (at -196 degrees Celsius) may be applied by swab or in a spray. More often, liquid nitrogen-cooled cryoprobes are pressed on lesions. Cryoprobes are cylindrical, with flat contact surfaces. The duration of cryoprobe use depends on the lesion size and type. For example, genital warts of the cervix are treated by quick freeze, a several-minute thaw, and refreezing.
Treating cancer is more complex. In treating internal cancer, liquid nitrogen is circulated through a cryoprobe touching the lesion. Its position and cell freezing are monitored by ultrasound, which also minimizes the destruction of healthy tissue and identifies the extent of cancer death. The size of the cryoprobe depends on the size of the lesion. If a lesion is not destroyed entirely, then the number of FTCs and the treatment time can be lengthened at follow-up visits.
Uses and Complications
The complexity of cryosurgery varies. Cervical warts require one FTC and a cryoprobe without any anesthetic. Because of the possibility of postoperative fainting, patients are observed for twenty minutes and should arrange for a ride home. Mild abdominal cramps or vaginal discharge may occur. The surgeon should be contacted about prolonged bleeding, infection, or cramps lasting more than twenty-four hours.
Most skin cancers, most often basal and squamous cell carcinomas, can be treated cryosurgically. Often, three or four FTCs are used. Ear, eyelid, and nose cartilage sites are good targets because scarring and necrosis of surrounding tissue are rare. Superficial basal cell carcinoma exhibits a near 100 percent cure rate, as do nose and ear lesions because these cancers rarely enter cartilage. Squamous cell carcinoma often does, however, and is harder to treat without creating scars. Cryosurgery is the treatment of choice for facial Bowen’s squamous cell carcinoma, with a cure rate near 100 percent, and for cancers of the cervix or penis; removing these cancers does not leave scars. Treating lesions on the eyelids, however, may cause them to swell shut.
Cryosurgery can also be used for localized prostate cancer. Warm saline is passed through a urethral catheter to prevent freezing. Cryoprobe placement is achieved through incisions between the anus and scrotum, guided by ultrasound. As with conventional surgery, anesthesia is needed for pain. The appearance of prostate tissue changes during cryosurgery and damage to healthy tissue can be minimized through the observation of ultrasound images. The prostate gland swells postoperatively, and a catheter in the bladder is used to prevent urination stoppage. This complication and bruises from probe insertion sites can result in hospital stays. However, cryosurgery causes less bleeding, shorter hospitalization and recovery periods, and less pain than does surgical removal of the prostate. Assurance of complete cancer destruction requires follow-up with radiation or chemotherapy.
Cryosurgery is also used to treat liver, pancreas, and breast cancers, and some types of low-grade tumors of the bone. The applicability of cryosurgery to breast, colon, and kidney cancers is under study. In these cases, cryosurgery is part of a mixed treatment, including conventional surgery and radiation or chemotherapy. Initial reports are encouraging, but the long-term effectiveness here is unknown. When standard treatments fail or are unusable in primary or secondary liver cancer, cryosurgery may be used alone. If the surgical removal of cancer from other internal organs is impossible, then cryosurgery may be used to increase symptom-free survival time.
With all cryosurgeries, the discoloration of treated areas and minor scarring may occur. The skin can lose pigment, sweat glands, and hair follicles. Therefore, cryosurgery is less desirable for dark skin and is not suggested for lesions at sites where alopecia (hair loss) would be a problem.
Perspective and Prospects
The first use of cryosurgery was in the early twentieth century through liquid air freezing for skin cancer treatment and cosmetic surgery. In the mid-1950s, improved cryotools began the expansion of cryosurgery to its modern state. This progress was enhanced by the availability of liquid nitrogen, which enabled clinicians to work at temperatures of -196 degrees Celsius.
Cryosurgery is a standard method used in cosmetic surgery and the treatment of skin cancers and is accepted for use with other cancers, including prostate, liver, pancreatic, uterine, lung, and brain cancers. Cryosurgery is employed alone and with other treatments (such as traditional surgery) or when other methods fail. After cryosurgery, many patients regain a high quality of life and are pain-free. Moreover, they are often outpatients, spend little time in surgery, have short hospitalizations, and recuperate rapidly. Scarring is minimal, and cure rates are high.
Cryosurgery has side effects, though they are less severe than those of traditional surgery. In treatment of the liver, cryosurgery may damage bile ducts or blood vessels, causing hemorrhage or infection. In the treatment of prostate cancer, it may cause incontinence and impotence. The main disadvantage, unclear long-term value in internal cancer surgery, is sure to be addressed.
Bibliography
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Peterson, Elizabeth A., Michael J. Fucci. “Cardiac Catheter Cryoablation.” Health Library, 26 Nov. 2012.
Usatine, Richard, et al. Cutaneous Cryosurgery: Principles and Clinical Practice. 4th ed. CRC Press/Taylor & Francis Group, 2021.
Wechter, Debra G., et al. “Cryotherapy.” MedlinePlus, US National Library of Medicine, 28 July 2015, medlineplus.gov/ency/article/007506.htm. Accessed 18 Jan. 2017.
Xu, Kecheng, Nikolai N. Korpan, and Lizhi Niu. Modern Cryosurgery for Cancer. World Scientific, 2012.