Smoking is not the only cause of lung cancer.

"It's a heterogeneous group of people who get lung cancer these days," said Dr. Linda Garland, director of clinical research in thoracic oncology at The University of Arizona Cancer Center in Tucson.

Garland says she's seen a stigma attached to lung cancer, where people blame the patient and think it's something they brought on themselves by smoking. But that is not an accurate picture.

Secondhand smoke exposure, and exposure to uranium and radon, are all associated with causing lung cancer in nonsmokers, she said. And nonsmokers who live in very polluted cities get lung cancer at a higher rate than people who live in a very clean environment.

Other cases are attributed to genetics.

The good news for people whose lung cancer is related to genetic abnormalities is that there are oral drugs that have proven very effective in shrinking tumors.

"The interesting thing is we've come to find a lot of very important information about 'never smokers' ' lung cancer in that we now have defined three very specific genetic abnormalities and those drive the lung cancer," Garland said.

"These driver mutations or fusion genes create in a very simplistic way a very activated pathway that leads to proliferation, ability to metastasize, replication potential - all the things that define a cancer cell."

When a tumor is removed, it can be tested for the three genetic abnormalities and if one is found, the patient can be treated with one of two cancer medications that became available in the last 15 years. When the gene mutation is targeted with the right medication, very rapid, very significant tumor shrinkage can occur, Garland said.

"Sometimes it looks like you've got the electrical circuit to Los Angeles County and you take the main breaker and turn it off. It's very dramatic," she said. "People can get some very prolonged, excellent benefit from these pills."

More people die of lung cancer than any other type of cancer, according to the Centers for Disease Control and Prevention. In 2008, the CDC says, 208,493 people were diagnosed with lung cancer and 158,592 people died of it.