Story highlights Lung cancer is the most common cancer worldwide

15% of patients diagnosed with lung cancer have no history of tobacco use

If you have a cough that lasts longer than a couple weeks, get it checked out

Ashley Rivas was 26 when she noticed she was getting tired earlier than usual on her runs. Over the next few years, the X-ray technician from Albuquerque, New Mexico, developed a persistent cough and wheezing, which her doctors attributed to exercise-induced asthma. She had other symptoms, too: weight loss, fever, and several bouts of pneumonia.

Still, when Rivas finally decided to perform a chest X-ray on herself, cancer was the last thing on her mind.

The image revealed a mass on her right lung that turned out to be a malignant tumor. Rivas was 32 and had never smoked a cigarette in her life. "I want people to know lung cancer can happen to anyone," she says.

Rivas has joined the American Lung Association's Lung Force campaign, to spread the word that her disease isn't just a smoker's affliction. "It's true that the majority of people with lung cancer have some history of tobacco use," says Lung Association spokesperson Andrea McKee, MD, the chair of radiation oncology at Lahey Hospital Medical Center in Burlington, Massachusetts. "Having said that, 15% of patients diagnosed with lung cancer have no history of tobacco use -- and they may be quite young."

Other known risk factors aside from smoking include a family history of the disease, as well as exposure to certain air pollutants, such as asbestos, arsenic, radon, even diesel fumes, says Dr. McKee. Lung cancer is the most common cancer worldwide; and each year, it kills more women than breast, ovarian, and uterine cancer combined.

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