Skin Cancer 101

Gino Bottino, MD


As I write this, the Northeast is having the first nice spring day of the year—sunny and relatively warm, a harbinger of the sunny days to come. As a result of sun exposure, however, over 1.6 million Americans will be diagnosed with skin cancer this year, and 10,000 will die of the disease. The number of skin cancer cases has doubled in the past 10 years, and the death rate is also rising. An estimated one in five Americans will develop skin cancer during their lifetime.

Skin cancers—basal cell, squamous cell and melanoma—account for the majority, nearly 40%, of all cancers. Certain individuals are more prone to skin cancer: Those with fair skin, light complexion, freckles, blond or red hair, and blue or green eyes. In addition, having a close relative with melanoma tends to increase the risk.

By definition, cancer is diagnosed when cells grow out of control and invade other tissue. The diagnosis is confirmed by a skin biopsy.

Our immune system helps to monitor the skin for abnormal cells and can stop them from growing. Because of this, individuals with immune system diseases or those on immune-suppressing medications are at increased risk of skin cancer. Increasing age is also a risk factor for basal cell and squamous cell cancers. However, advanced skin cancers can occur in younger individuals. In fact, melanoma is the most common cancer in people from 25 to 30.

basal cell cancer

Basal cell cancer

The most common of all cancers and the most common skin cancer, basal cell cancers arise primarily in sun-exposed areas from cells in the basal layer of the skin that grow abnormally. It most commonly presents as a sore that won’t heal, but it can be a nodule or spot that grows over months and generally does not cause pain. In general, basal cell cancers are successfully treated with minor surgery and rarely spread.

Squamous cell cancer

The next most common skin cancer, squamous cell cancers arise in the top or squamous layer of skin. Like basal cell cancers, they tend to occur in sun-exposed areas like the face, nose, ears, shoulders, neck, forearms and backs of the hands. Although they can present as sores, they most commonly appear as hard, crusty growths. These cancers may develop from abnormal skin growths called actinic keratoses. These precancerous growths can be treated by freezing with liquid nitrogen or creams. Once it has progressed to squamous cell cancer it can be treated with freezing, surgery, or topical chemotherapy.

melanoma cancer


Melanomas make up about 5% of all skin cancers, but they cause 98% of skin cancer deaths. In 2020, melanoma was responsible for over 7,000 deaths out of over 196,060 cases diagnosed in the U.S. These cancers arise from the skin’s melanocytes or pigment-producing cells. Melanomas can occur in young people, and while they are mostly in sun-exposed areas, they can occur anywhere. One blistering sunburn in childhood more than doubles a person’s chances of developing melanoma later in life. Regular sun protection throughout childhood can reduce the risk of skin cancer by 80%.

The characteristics to watch for in a mole are asymmetry (meaning it tends to have an irregular shape), irregular borders, changes in color especially dark or black tissue, and growth of the mole. Melanomas are best treated with surgery when found early. The danger of melanoma is that it can spread to other parts of the body. If it spreads, treatment becomes much more difficult.

Sunscreen saves lives

When applying sunscreen, pay particular attention to the face, ears, hands, and arms, and generously coat the skin that isn’t covered by clothing.

One ounce of sunscreen, enough to fill a shot glass, is considered the amount needed to completely cover the exposed areas of the body.

Reapply sunscreen every two hours or immediately after swimming or strenuous activities.

The most important recent change in sunscreen is the formulation of some products to block ultraviolet radiation type A. Ultraviolet type A, referred to as UVA, does not cause sunburn. As a consequence, most of the older formulations of sunscreen only blocked the sunburn-causing UVB. We now know that UVA is a large contributor in the development of skin damage and skin cancer.

The sun protection factor of sunscreen (the SPF) refers only to the product’s ability to block UVB radiation, not UVA. The SPF number on the sunscreen’s label tells you only how much longer you can remain in the sun with the sunscreen on than you could without it. For example, an SPF of 15 will allow you to be in the sun without turning red 15 minutes longer than your normal unprotected “MED.” Your “MED” is the measure of the sun’s energy it takes for your skin to turn red.

To achieve UVA protection, you must check that your sunscreen contains one or more of the following additives: benzophenone, oxybenzone, sulisobenzone, titanium dioxide, zinc oxide, or avobenzone, a sunscreen chemical recently approved by the Food and Drug Administration and sold under the brand name Parsol 1789.

In the past, the government has recommended an SPF of 15 because this would allow the average fair-skinned American five hours of protection between the hours of 10 a.m. and 3 p.m. With the depletion of the ozone layer, it’s probably advisable to use even higher SPF. If you are fair-skinned, use an SPF of 29 with one of the UVA protectants.

Gino Bottino, MD

Gino Bottino, MD, has had wide experience in medical practice and emergency medical matters. A member of United States Power Squadrons First Aid Support Team (FAST) and the Safety Committee, Gino also has a background in competitive sail racing and is familiar with health-related problems afloat.

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