Skin cancer is the uncontrolled growth of abnormal cells in the outermost layer of skin. The rapid proliferation of these cells results in the formation of malignant tumors.
The main causes of skin cancer are the sun’s ultraviolet rays and the use of indoor tanning equipment. Skin cancer is the most common cancer in the United States and also one of the most treatable. This is because skin cancer in its earliest and precancerous stages can often be detected with the naked eye, simply by engaging in regular skin examinations, including self-exams.
The most common forms of skin cancer are basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Merkel cell carcinoma (MCC) is also among the most common despite being much rarer. Each form has somewhat different symptoms, levels of magnitude, and medical implications.
Basal cell carcinoma is the most common form of skin cancer. Over 4 million cases of BCC are diagnosed in the United States each year.
BCC typically appears on any area of the body that is exposed to the sun, which can include the face, hands, back, shoulders, ears, neck, and scalp. Accordingly, BCC is caused by prolonged or repetitive exposure to sunlight. While BCC can be destructive to its immediate area on the skin, fatalities from BCC are rare.
Squamous cell carcinoma is the second-most common form of skin cancer; over 1 million cases of SCC are diagnosed every year.
Like BCC, the most common cause of SCC is sunlight exposure and it occurs in many of the same places on the body. If detected and treated early, SCC has a high success rate. If SCC goes undetected and is allowed to metastasize, however, it can grow rapidly. Squamous cell carcinoma is responsible for about 16,000 deaths every year.
Melanoma is more serious than BCC or SCC. About 192,000 cases of melanoma were diagnosed in 2019.
While sun exposure and tanning bed usage increase the risk of melanoma considerably, it can appear even in areas where sunlight does not reach, such as the inside of the mouth, underarm, or groin area. This makes it harder to detect. While it causes over 7,000 deaths a year, melanoma can be successfully treated and removed if detected in its early stages.
Of all the most common types of skin cancer, Merkel cell carcinoma is both the most rare and the most serious. MCC is an aggressive cancer that usually appears on sun-exposed areas, specifically the head and neck, as well as the eyelids. It generally appears in people over the age of 50.
MCC is unique in that it usually originates with a virus—Merkel cell polyomavirus—which interacts with the Merkel cells at the base of the epidermis. While only 2,500 cases of MCC are diagnosed each year, around 700 deaths result from it, which is only around a 28% survival rate. This illustrates the absolute need for early detection and treatment, which can improve a patient’s chances.
Skin cancer, in all of its forms, has a much higher chance of being successfully treated if it’s detected early. The best way to detect skin cancer or any skin condition is with regular self-examinations and annual full-body examinations by a board-certified dermatologist.