Who's got your back for skin cancer prevention?

The return of warm weather has millions of Americans heading outside to soak up the sun. It feels especially welcome in the Northeast after a seemingly endless winter. But sun exposure is a leading cause of melanoma, the deadliest form of skin cancer, so it's important to take steps to protect yourself.

The American Academy of Dermatology points out that the back is the most common place on the body for melanoma to develop, and because it's a difficult area for a person to see, skin cancers on the back are often discovered later and require more extensive treatment.

To raise awareness, the group has declared May 4 #MelanomaMonday and launched a public awareness campaign to encourage Americans to watch their backs.

"Before you head outside, it's important to apply a water-resistant, broad-spectrum sunscreen with a Sun Protection Factor [SPF] of 30 or higher to all exposed skin, including the back," Academy president and board-certified dermatologist Mark Lebwohl, MD, said in a press statement. "Since applying sunscreen to your own back can be difficult, it's best to ask for someone else's help."

A survey conducted by the group found 37 percent of people rarely or never apply sunscreen to their back when it's exposed to the sun, and 43 percent rarely or never ask anyone to help apply sunscreen to their back. Men were twice as likely as women to report that they didn't feel comfortable asking anyone to apply sunscreen to their back.

But doctors say, get over it -- your life could be at stake. "Find someone you're comfortable with -- like a significant other, friend or relative -- and ask them to apply sunscreen to your back. Or even better, stay in the shade and wear clothing that covers your back," Lebwohl said.

• What you don't know about sunscreen could hurt you
• Summer sun safety: Tips for preventing skin cancer or catching it early

American Cancer Society says more than 3.5 million people are diagnosed with skin cancer in the U.S. each year. A majority of cases involve basal or squamous cell skin cancer, which can usually be removed before they spread, but about 73,000 Americans each year are diagnosed with melanoma, which can be fatal.

The infographic below has more advice on the importance of protecting your back and all other exposed skin from the sun. You can get more information about how to screen for skin cancer and what warning signs to look for on the American Academy of Dermatology website, SpotSkinCancer.org.