Squamous cell carcinoma (SCC) is the second most common type of skin cancer . It is more common in men than women at a 2: 1 ratio. The incidence of squamous cell carcinoma among Caucasians in the United States is 0.1 to 15% per year. The incidence increases with age and the peak incidence of this skin cancer occurs at 66 years of age. The incidence also increases with decreasing latitude, for example, in the southern United States and Australia.
What is squamous cell carcinoma?
Squamous cell carcinoma occurs in the outer layer of the skin, the epidermis , and causes mutations in cells called keratinocytes. UVB radiation is important for the induction of this skin cancer, which damages DNA and its repair system, and also causes mutations in tumor suppressor genes. These mutated cells spread across the surface and cause a change in the appearance of the skin. When mutated cells invade the dermis, the risk of metastasis increases.
Some common risk factors for squamous cell carcinoma include:
- Chronic sun exposure mainly due to UV-B radiation, but also UV-A rays
- A precancerous condition called actinic keratosis or solar keratosis.
- Suppressed immune system
- HIV disease
- Ionizing radiation from acne in the 1940s
- Shiny skin
- Tobacco use
Some rare risk factors for squamous cell carcinoma include:
- Exposure to arsenic
- Exposure to cyclic aromatic hydrocarbons in tar, soot or shale
- Scars or previously damaged skin, especially radiation damage
- Infection with human papillomavirus types 6, 11, 16 and 18
- A rare genetic disorder called xeroderma pigmentosa.
Squamous cell carcinoma appearance
A change in the skin caused by squamous cell carcinoma often looks like a scab. There may be thick adherent scales on the inflamed red base. The scab usually heals significantly within 2 weeks. However, squamous cell carcinoma cannot be cured and may bleed intermittently. As it spreads to the dermis, this skin cancer can look like an ulcer with raised, hard edges. Squamous cell carcinoma is most often found in sun-exposed areas, such as the back of the hand, the scalp, the lip, and the top of the ear.
The only way to diagnose squamous cell carcinoma is with a biopsy of the suspicious growth. The preferred type of biopsy is called a post-shave biopsy, in which the lesion is shaved with a flexible razor. Another biopsy option, depending on the extent of the lesion, is excision of the lesion. Helpful information, such as whether the tumor has been completely removed and the depth of the tumor, can only be obtained with a biopsy.
Treatment options for this skin cancer depend on the information obtained from the biopsy.
Electrodesiccation and Scraping : This procedure involves removing the skin cancer with an electrocoagulator and then scraping it off with a curette. Diseased tissue can often be distinguished from normal tissue by the texture felt during scraping. This process is repeated several times to completely eliminate skin cancer. This procedure is useful for small tumors with a diameter of 1 cm or less on the neck, trunk, arms, or legs. However, this usually leaves a scar.
Simple excision: This procedure involves the surgical removal of a tumor from the skin, including the border of normal skin. For tumors 2 cm or less, 4 mm is sufficient; for tumors> 2 cm, the best margin is 6 mm. The advantage of this treatment is that it is fast and inexpensive. However, the difference between normal and cancerous tissue must be assessed with the naked eye.
Mohs Micrographic Surgery – This procedure should be performed by an experienced Mohs surgeon. It involves removing the skin cancer and immediately examining the tissue under a microscope to determine the boundaries. If any residual skin cancer remains, it can be mapped and removed immediately. The border removal and examination process may need to be repeated several times. The advantage of this method is that it is generally definitive and has been reported to have a lower recurrence rate than other treatment options. The downside is time and cost.
Radiation therapy: This procedure involves a cycle of radiation therapy to the tumor area. However, there is currently insufficient evidence that radiation after surgery improves the recurrence rate of squamous cell carcinoma. It can also have long-term effects in the form of scars, ulcerations, and thinning of the skin.
Chemotherapy. The type of chemotherapy used is 13-cis-retinoic acid and interferon-2A. Chemotherapy is used for advanced squamous cell carcinoma.
Cryotherapy: This procedure involves the destruction of tissue by freezing it with liquid nitrogen. It can be effective for small, well-defined superficial skin cancers. It is also used effectively to treat actinic keratosis, a precancerous condition. This procedure is inexpensive and time-effective, but it can only be used in a small number of cases.
Avoid UV-B radiation from sun exposure. Avoid the midday sun, wear protective clothing, and use a sunscreen with an SPF of at least 15. This is especially important for children.
Avoid tobacco products – This includes cigars, cigarettes, chewing tobacco, and snuff. Since these products increase the risk of squamous cell carcinoma of the lips and mouth, their use should be reduced or eliminated.
Avoid Polycyclic Hydrocarbons – Jobs that require contact with these compounds are highly regulated. Always wear protective equipment when handling these compounds.
Investigate suspicious injuries. If you have questions, please review them. Treatment of precancerous lesions prevents them from transforming into potentially metastatic skin cancer.