Melanoma may account for a small percentage of skin cancers, yet it causes an estimated 75 to 80 percent of skin cancer deaths. Caught early, it has a 99 percent five-year survival rate, but if it slips patients’ and clinicians’ notice, digs deeper into the skin and spreads beyond the lymph nodes, that rate can drop to 25 percent, according to the National Cancer Institute. The ACS predicts there will be 6,850 deaths in the United States from melanoma this year.

Although more skin pigment provides more protection, melanin itself has a sun protection factor, or SPF, of less than 5, says Fisher, suggesting that it functions physiologically as more than mere sunblock. He and others have clarified how different types of melanin raise or lower melanoma risk, and they’ve shown that any minimal benefit provided by tanning, such as the production of vitamin D, doesn’t outweigh the DNA damage caused by UV exposure.

Skin cancers are far and away the most common cancers in the United States. Basal and squamous cell carcinomas make up the vast majority, with somewhere between 1 million and 5.4 million new instances diagnosed each year. However, because these two malignancies don’t have to be reported to cancer registries, precise numbers aren’t known: The cancer officially ranked as the most common in this country is breast cancer, with 270,000 new cases each year. Melanoma is ranked fifth, with about 100,000 new diagnoses expected in 2020, reports the American Cancer Society (ACS).

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