More than 3.5 million skin cancers are diagnosed each year in the United States, making it the most prevalent of all cancers. It is more common than cancer of the breast, prostate, lung, and colon combined. It is estimated that 20% of Americans will develop skin cancer in their lifetime. Although it is very widespread, there is some good news:
- Since most skin cancers are caused by excessive sun exposure, prevention measures can significantly reduce your risk of getting skin cancer
- Awareness of skin cancer warning signs enables treatment at an early stage thereby minimizing the risk of spreading or recurrence
Basal and squamous cell cancers (keratinocyte cancers) are the most common forms of skin cancer. They are found mainly on parts of the body exposed to the sun, such as the head and neck. These cancers rarely spread elsewhere in the body and are much less likely than melanomas to be life threatening. Although they grow very slowly, both of these types of skin cancer can become quite large and affect nearby tissues. Scarring, disfigurement, or even functional loss may be the outcome if they are ignored or left untreated.
Melanomas can occur anywhere on the body but certain locations are at higher risk. Women are most commonly affected on the legs, neck, and face while the chest and back have the highest incidence in men. Melanomas can be much more invasive than basal cell and squamous cell cancers, but are almost always curable in their early stages. Disability and death can result if melanoma spreads to other parts of the body.
Basal cell carcinomas have a range of appearances. They may appear flat, firm, and pale in color but can develop as a small, raised, pink or red growth on your skin. A characteristic translucent, shiny, or waxy surface may be evident. They also may be prone to bleed after a minor injury. Multiple small blood vessels may be apparent on the surface. Sometimes the central portion of the lesion may have a crater-like depression and blue, brown, or black areas may be present. Large basal cell carcinomas may have oozing or crusted areas.
Squamous cell carcinomas typically look like lumps that will gradually increase in size if left untreated. The surface is usually rough, scaly, and crusted. These carcinomas may also appear as flat red patches that grow very slowly.
Melanomas are flat or raised pigmented areas on the skin that appear to change in size, shape, or color over time. They also frequently look different from moles or skin pigmentation present elsewhere on your body.
The ABCD rule is a guide for any signs of change in a pigmented skin lesion that should immediately be brought to the attention of your doctor:
(A) Asymmetry – meaning each half of the skin lesion or growth appears different
(B) Border irregularity – meaning the edge of the lesion is uneven
(C) Color irregularity – meaning the color of the lesion is not uniform and may have several different shades
(D) Diameter – meaning the diameter is relatively large (over 5 mm)
The ABCD rule does not apply in every case, so it is important to be aware of any changes that occur in skin lesions that have been present for a long time. In addition, new skin lesions or lesions that look different from the rest of your moles need to be carefully monitored.
An annual body check by a physician is especially important if you have a history of extensive sun exposure. Any lesions that develop ulcerations and are eroding or enlarging need to be evaluated.
In the next blog, prevention and treatment of skin cancers will be discussed.