Cryosurgery (cryotherapy; icing) involves the targeted icing of benign (benign) and malignant (malignant) skin lesions and is referred to as a physical destructive method. The consequence of the rapid drop in temperature is a so-called cryonecrosis or cryodestruction, which means the destruction of the diseased tissue. In this way, both harmless warts and dangerous skin tumors can be treated.
Indications (areas of application)
- Actinic keratoses – cornification disorder of the skin caused by radiation (especially UV radiation) (precancerous stage; risk factor for squamous cell carcinoma).
- Angiokeratomas – so-called blood wart; benign skin changes consisting of wart-like hyperkeratosis (excessive keratinization of the skin) combined with telangiectasias (extension of small, superficial skin vessels) or angiomas (blood sponge; tumor-like formation of new vessels)
- Basal cell carcinoma (BZK; basal cell carcinoma) – semi-malignant (conditionally malignant) tumor of the skin, which is characterized by slow growth and very rarely forms metastases (daughter tumors).
- Basal cell nevus syndrome, naevoid phase – hallmarks of this disease are numerous superficial basal cell carcinomas, which in the further course pass into true basal cell carcinomas.
- Cheilitis actinica – radiation-induced inflammation of the lower lips, caused by sunburn or chronic sun exposure.
- Erythroplasia queyrate – a precancerous (cancerous) condition of the skin caused by human papillomaviruses and occurs on the genitals
- Fibromas – benign connective tissue tumor.
- Granuloma anulare – non-infectious granulomatous skin disease; coarse, ring-shaped, closely spaced, reddish nodules of the dermis (dermis).
- Hypertrophic scars – strongly grown scar tissue.
- Keloids (bulging scars)
- Cutaneous melanoma metastases – skin metastases (daughter tumors in the skin) of malignant melanoma.
- Lentigines/Lentigo maligna – so-called lentigines or liver spot, which is caused by increased activity of melanocytes (cells that stain the skin brown) and can develop into malignant melanoma
- Leishmaniasis (kala-azar) – parasitic disease transmitted by a small insect (sand fly (Phlebotomus)), which leads to ulcerative (ulcer-like) skin lesions.
- Leukoplakia – so-called white callus disease characterized by a white flat mucosal lesion. Leukoplakia can progress to squamous cell carcinoma (prickle cell cancer).
- Lichen ruber verrucosus – inflammatory nodular lichen of the skin and mucosa with a wart-like appearance.
- Eyelid tumors
- Lip margin angiomas – tumor-like neoplasm due to vascular sprouting at the lip margin.
- Lupus erythematosus (SLE) – systemic disease affecting the skin and connective tissue of the vessels, leading to vasculitides (vascular inflammation) of numerous organs such as the heart, kidneys or brain, as well as characterized by various types of erythema (inflammation-related redness of the skin)
- Bowen’s disease – so-called Bowen’s skin cancer, the precursor of which can be caused by human papillomavirus, arsenic exposure and UV light.
- Nevus teleangiectaticus – a variant of nevus flammeus (port-wine stain; light to dark brown spots caused by capillary dilation) with planar telangiectases (usually acquired dilation of small, superficial skin vessels)
- Necrobiosis lipoidica – inflammation of the middle dermis with accumulation of lipids, leading to necrosis (tissue death).
- Prurigo nodularis – rare, chronic skin disease with large, itchy, coarse nodules with a rough surface.
- Pseudolymphoma – benign, regressive proliferation (growth by cell division) of lymphoid tissue.
- Infant hemangiomas – benign neoplasm of small vessels (capillaries) in the skin (= blood sponge) in newborns.
- Seborrheic keratoses (synonyms: seborrheic wart, age wart, verruca seborrhoica) – most common benign skin tumor caused by a proliferation of the so-called keratinocytes (horn-forming cells of the skin).
- Senile angiomas – age-related, tumor-like neoplasms caused by vascular sprouting.
- Verrucae vulgares – vulgar warts (common warts), which are also called prickly warts.
The procedure
Local icing of diseased tissue is performed by cooling it below -40 °C. To achieve this temperature, liquid nitrogen is usually used, which has its boiling point at -195.8 °C. Two forms of application are distinguished:
- Open spray process: The liquid nitrogen is sprayed directly onto the lesion from a short distance. This allows a fast, deep-acting result and reaches a depth of 12 mm.
- Contact method: A pre-cooled metal stamp or a probe perfused with liquid nitrogen are placed directly on the lesion. The choice of different probes guarantees a gentle icing of circumscribed lesions and reaches a depth of about 4 mm.
The effect of icing is characterized by a variety of processes that result in cell destruction. Tumor cells are particularly sensitive to cold because they have a high water content. The following mechanisms lead to cryonecrosis (tissue death due to cold):
- Phospholipid denaturation of the cell membrane – The cell membrane is composed of special fats that change their structure during icing, so that the membrane is destroyed.
- Mechanical damage to the cell membrane due to the formation of ice crystals, especially during recrystallization during the thawing process.
- Mechanical damage to cell organelles (e.g. mitochondria).
- Emergence of toxic (poisonous) concentrations of intracellular (located inside the cell) electrolytes.
- Stagnation of metabolic processes
The success of the process depends on the temperature reached, speed, cooling and thawing process. Optimal is a cooling rate of 100 Kelvin/min (Kelvin: SI base unit of thermodynamic temperature and also legal temperature unit; it is also used to indicate temperature differences; the Kelvin scale begins at the absolute freezing point) and a spontaneous thawing process of less than 10 Kelvin/min. Therapeutic success can be improved by repeated application of local icing (especially in benign conditions). The duration of icing is 10-60 seconds and depends on the skin lesion, its size, localization and icing method. Cryosurgery is usually performed on an outpatient basis, although individual cases may require hospitalization (e.g., eyelid or finger treatments). Prior to treatment, a punch biopsy (tissue sample taken through a punch) is usually performed followed by histological confirmation (viewing of a tissue sample using a microscope), for example, to confirm the diagnosis of a malignant skin lesion. In most cases, local anesthesia is not required because cold anesthesia (insensitivity to pain from the cold) occurs after an initial stabbing pain.
Benefits
Cryosurgery makes a valuable contribution to the therapeutic options for benign and malignant skin lesions, especially in dermatology. It is versatile and highly effective.
