Squamous Cell Skin Cancer
This type of skin cancer arises from the squamous cells and is slow growing. Most cases (about 95%) can be cured with minimal damage if caught early and removed promptly. However, new tumors may develop.
Treatment varies and is based on the type, location, size, and depth of the tumor as well as the person’s age and general health. Although there are possible drug treatments for squamous cell skin cancer, common methods of removal are surgical procedures and radiation therapy. These include:
• Simple excision - The cancerous tissue, along with surrounding healthy tissue, is excised (cut out with a scalpel) and the site is sutured closed.
• Curettage and electrodesiccation - A curette is used to scrape off the growth and an electrocautery needle is used to kill remaining cancer cells and control bleeding.
• Mohs micrographic surgery - This procedure removes the growth with a very thin layer of surrounding tissue. If cancerous cells are noted (under a microscope) in the depths or peripheries of the surrounding tissue, another very thin layer is removed and examined until the tissue is free of cancerous cells. This helps save healthy tissue.
• Cryosurgery - A liquid nitrogen is used to freeze and kill cancer cells.
• Radiation therapy - X-ray beams destroy the tumor. This normally requires a series of treatments and no anesthesia or cutting are needed.
The following are possible drug treatments for squamous cell skin cancer:
Imiquimod and 5-fluorouracil (5-FU)
Both of these drugs are FDA approved for the treatment of actinic keratoses (precancerous lesions that can develop into squamous cell cancer). They are currently being tested for the treatment of superficial squamous cell skin cancer and have had positive results in treating the earliest form (called squamous cell carcinoma in situ or Bowen’s disease). Some trials suggest imiquimod may be helpful with some invasive squamous cell cancers but is not FDA approved at this time for this purpose. 5-FU should not be used to treat invasive cell carcinoma.
Imiquimod, a cream, is believed to work by activating the immune system to fight off abnormal skin growths. When treating actinic keratoses, it is normally applied twice a week for 16 weeks. Possible side effects include redness, swelling, pain, burning, itching, peeling, and thickening/hardening of the skin. Women who are pregnant or breastfeeding should avoid use.
5-fluorouracil is also applied topically. It is a chemotherapy drug that kills abnormal cells by halting cell division and by inducing cell suicide (apoptosis). When treating actinic keratoses, it is normally applied twice a day for several weeks. Possible side effects include darkening of the skin and dry, cracking, peeling skin. Women who are pregnant or breastfeeding should avoid use.
Photodynamic therapy (PDT) is especially helpful for growths on the scalp and face. A photosensitizing drug, like 5-aminolevulinic acid (5-ALA), is applied to the growth which is taken up by abnormal cells. The next day, a strong light is used to destroy the abnormal cells. Damage to healthy tissue is minimal. PDT is used to treat actinic keratosis but is not yet FDA approved for squamous cell carcinoma. While it may be helpful with early, noninvasive growths, it is not recommended for invasive squamous cell cancer. Common side effects include redness and swelling.
Medline Plus: Squamous cell skin cancer - https://www.nlm.nih.gov/medlineplus/ency/article/000829.htm
Skin Cancer Foundation: Squamous Cell Carcinoma Treatment Options - https://www.skincancer.org/scc-treatment-options.html
WebMD: Imiquimod - Topical - https://www.webmd.com/drugs/drug-1191-Imiquimod+Top.aspx?drugid=1191&drugname=Imiquimod+Top&source=2
Chemocare: Chemotherapy Drugs 5-Fluorouracil - https://www.chemocare.com/bio/fluorouracil_t.asp
Images courtesy of the National Library of Medicine (NLM)