- Skin cancer is the most common cancer in the United States.
- Basal cell carcinoma accounts for 70 - 80% of the total.
- Squamous cell carcinoma accounts for 20%.
- This does not include melanoma which is classified separately.
- Some of the risk factors include fair complexion, tendency to sunburn easily, radiation induced dermatitis, thermal burns, certain scars and chronic ulceration.
- Among the environmental causes, exposure to sunlight, primarily ultraviolet-B rays is most significant.
- The incidence is maximum at lower latitudes.
- Arsenic exposure, transplantation and subsequent immunosuppression by medication, human papilloma virus and HIV are some of the other risk factors.
BASAL CELL CARCINOMA
- This malignancy arises from epidermal basal cells.
- This is most common on trunk and extremities.
- The lesions sometimes can be mistaken for benign conditions like eczema and psoriasis.
- Sometimes the lesions look like melanoma.
- The natural history is that of a slow growing locally invasive neoplasm.
- The metastatic potential is very low, estimated to be less than 0.1%.
- As a result, most of the lesions are curable.
- Electrodesiccation and curettage is the most commonly employed method of treatment.
- Excision is done for more aggressive tumors.
Some of the other modalities of treatment are:
- Cryosurgery with liquid nitrogen.
- Mohs micrographic surgery.
- Topical chemotherapy with 5-Fluorouracil.
SQUAMOUS CELL CARCINOMA
- This is a cancer of keratinizing epidermal cells.
- Unlike basal cell carcinoma, it can grow rapidly and has high metastatic potential.
- It can develop anywhere in the body but usually arises on sun damaged skin.
- This usually appears as an ulcer.
- There are several lesions which can be said to be premalignant forms - actinic keratosis, actinic cheilitis.
- Bowen's disease is localized only to epidermis (called in-situ).
- Early recognition and treatment of these lesions that predispose to cancer and in-situ lesions can prevent subsequent development of invasive disease.
- Metastatic spread is much higher in these skin cancers, 0.3 to 3.7%.
- Lesions of the lower lip, chronic ulcerations, scars and genitalia is even higher.
- Surgical excision, radiation and Mohs micrographic surgery are standard methods of treatment. The treatment is more aggressive and definitive as compared to basal cell carcinoma. Majority of lesions are curable.
- Since majority of skin cancers are related to chronic UV-B exposure, they can be prevented by reducing exposure to UV-B rays beginning early in life.
- Sunscreen should be used regularly and sun exposure avoided from 10:00 a.m. to 2:00 p.m.
- Tanning salons should be avoided.