Skin cancer is the most common type of cancer in America with more than a million patients diagnosed annually in the United States – and it is becoming more common every year. Worryingly, it also is affecting younger people.

Between 1980 and 2004, the annual incidence of melanoma among 15- to 39-year-old women increased by 50 percent, from 9.4 to 13.9 cases per 100,000 women. Melanoma is the most aggressive form of skin cancer.

If not detected early, it can spread through the body (metastasize) and cause death. Basal cell carcinoma and the majority of squamous cell carcinomas – the two most common types of non-melanoma cancer – respond well to treatment (most often surgery) and can be completely curable.

Non-melanoma skin cancers also are becoming more common in younger patients. One large population study conducted at the Mayo Clinic in Minnesota looked at non-melanoma skin cancers in people younger than 40. Between 1976 and 1979, roughly 18 out of 100,000 of them developed basal cell carcinoma, and one in 100,000 developed squamous cell carcinoma.

Between 2000 and 2003, those figures had risen to 29 out of 100,000 for basal cell carcinoma and four out of 100,000 for squamous cell carcinoma. The increases were especially great in women: The number of women younger than 40 diagnosed with basal cell carcinoma more than doubled.

Use Sunscreen. Lots of Sunscreen

In my own practice as a dermatologic surgeon, I commonly diagnose and treat skin cancer in patients in their 20s and early 30s. Many of the tumors I treat are preventable with the use of sunscreen and sun protective measures. UV light exposure damages DNA in skin cells, causing mutations that form cancer cells.

It also suppresses the immune system, potentially decreasing the body’s ability to fight off cancerous changes in the skin.

When using sunscreen, you should generously apply a broad-spectrum, water-resistant sunscreen with a sun protection factor, or SPF, of 30 or greater, especially during the peak hours of 10 a.m. to 4 p.m. Broad-spectrum means the sunscreen effectively blocks both UVB and UVA light; the SPF rating refers only to the sunscreen’s ability to block UVB light. While UVB is the main cause of sunburns, both UVB and UVA contribute to skin cancer formation and photoaging, or the visible changes of aging, such as wrinkles and brown “age spots.”

Unfortunately, there is no current FDA-approved standard for rating a sunscreen’s efficacy in blocking UVA rays; however, a rating system is currently being developed.

Sunscreens that contain titanium dioxide and zinc oxide do a good job of blocking both UVA and UVB rays. Other common sunscreen ingredients with good UVA coverage include avobenzone, ecamsule (or Mexoryl™) and oxybenzone.

Although most people are aware that properly applied sunscreen can reduce the risk of skin cancer, questions and misconceptions about sunscreen abound. Here are a few of the most

commonly asked questions:

Is sunscreen with SPF 70 better than SPF 30?

Sunscreen with SPF 30 blocks 97 percent of UVB rays, if adequately applied. The rating assumes an optimal standardized amount of sunscreen is applied (2 mg/cm2).

This is about one ounce (the size of a shot glass) to cover the exposed areas of the body adequately, or about 1/4 to 1/3 of a teaspoon for just the face. Studies have shown that the average person uses only half or even a quarter of that amount.

This downgrades the SPF to a square or fourth root of the labeled value. For example, an SPF 70 sunscreen would be downgraded to roughly SPF 3 to 9. The bottom line is that a sunscreen with an SPF of at least 30 provides good UV protection if an adequate amount is applied. How often do I need to apply sunscreen?

Sunscreen should be applied 15 to 30 minutes prior to sun exposure and reapplied every two hours and after swimming or perspiring heavily. Don’t forget the ears and lips: Use a lip balm with sunscreen.

Can I use a tanning bed to get a base tan before the summer? No. In July 2009, the World Health Organization’s International Agency for Research on Cancer classified UV-emitting tanning devices as carcinogenic to humans, adding tanning beds to a list of other known carcinogens, including asbestos, tobacco smoking and arsenic. Analysis of multiple studies shows that the risk of melanoma is increased by 75 percent with use of tanning devices prior to the age of 30.

What about vitamin D?
Vitamin D is important for bone health, and vitamin D deficiency has been linked to increased risk of cancer – including breast, lung and colon cancer – and other diseases, such as multiple sclerosis.

Because vitamin D is synthesized in the skin after exposure to sunlight, some have claimed that purposeful sun exposure is necessary for vitamin D generation. However, vitamin D is also obtainable through diet.

The American Academy of Dermatology issued a position statement in 2008 stating that in order “to minimize the risk of UV-induced skin cancers, a comprehensive photoprotective regimen, including the regular use and proper use of a broad-spectrum sunscreen, is recommended.

This is especially important for those with fair skin, as the amount of UV exposure required to maximize vitamin D synthesis in the skin is far less than the sunburn dose.”

Vitamin D obtained from foods and dietary supplementation provides the same benefits as vitamin D from UV light without increasing the risk of skin cancer and visible signs of aging. I’m 55 years old. Does it really matter if I start using sunscreen now? It is never too late to use sunscreen.

While starting earlier better reduces your overall lifetime sun exposure, starting sun protection at any age can help prevent aging changes, skin cancer and pre-cancers, and it even helps the skin repair previous UV-induced cell damage. When should I see a dermatologist?

An annual skin examination is a good idea, especially if you have risk factors for melanoma or other skin cancer.

Get to know your skin. If you notice any skin lesion that has changed in size or pigmentation, that is bleeding or that just doesn’t seem right, you should see a dermatologist.

For more information, visit www.westlakedermatology.com.