When damaged cells on the skin begin to grow and divide uncontrollably, cancer of the skin develops. Skin cancer develops in the outermost layer of the skin (epidermis). So a tumor on the skin becomes clearly visible. Hence, most skin cancers are detected in the early stages. In the U.S., cases of skin cancer have grown dramatically, and studies show that 45-50% of all Americans who live until the age of 65 will develop at least one kind of skin cancer. Skin cancer can be broadly classified into 2 types: non-melanoma skin cancer and melanoma.
Non-melanoma skin cancer can be further divided into basal cell carcinoma and squamous cell carcinoma. These skin cancers are more common – at least 1 million new cases occur every year in the U.S. Melanoma is the more serious form of skin cancer because of its tendency to spread to other parts of the body.
Basal cell and squamous cell cancer:
Basal cell carcinoma (BCC) is the most common cancer in humans. This cancer occurs in the cells located in the lowest layer of the epidermis – the basal cells. BCC begins as a small bump that is covered by superficial blood vessels. The texture of this area is ‘pearly’. If the BCC contains melanin, the area may appear dark. BCC is most common in light colored people who are exposed to the sun for long periods of time. The face, ears, scalp and upper trunk are especially vulnerable. These tumors grow very slowly and take many years to reach even half an inch and they do not spread. But, as with any cancer, early detection and prompt treatment are the best ways to handle BCC.
Squamous cell carcinoma (SCC) begins in the squamous cell. These cells are found in the upper layer of the epidermis. Roughly 16% of skin cancers are SCC. Fair skinned middle aged and elderly people having a history of long exposure to the sun risk SCC. SCC is seen on the skin as a crusted scaly area with a red inflamed base that resembles a crusted-over patch of skin. This cancer can occur anywhere ranging from the inside of the mouth to the genitalia, although areas exposed to the sun are more vulnerable. SCC may arise from scaly lesions or from actinic keratoses. Lesions may occur many years after sun damage. Therefore people who were ‘sun worshippers’ in their twenties may develop cancer when they reach their early forties. SCC is slightly more dangerous than BCC and needs early treatment to prevent spreading. The lower lip is particularly prone to metastatic spread.
Melanoma begins in the cells called melanocytes. Melanocytes are spread throughout the lower part of the epidermis and they produce melanin (the coloring pigment). When melanocytes grow in clusters, they are benign and are commonly called moles. But when these melanocytes become malignant, cancer occurs. In men, melanoma is often found in the upper parts of the body – the trunk, head or neck. In women, the lower legs and the trunk are at risk. In dark skinned people, it develops under the fingernails, toenails, on the soles of the feet, or palms of the hands. Signs of melanoma include ‘ABCD’ – A: Asymmetry in shape, B: Jagged borders, C: Uneven colors with shades of gray, brown or black; and D: The diameter is big.
Surgical excision and radiation therapy work well with BCC and SCC. In the case of melanoma, if the cancer has spread to other areas, chemotherapy may be needed.
Avoiding overexposure to the harmful UV rays of the sun is the best way to prevent skin cancer.