Kirk Smith doesn’t care much for the word “awareness”— instead, he prefers the word “hope.”

The 54-year-old is training for a half Ironman triathlon in October while battling an aggressive, genetic-linked form of lung cancer that has a poor survival rate and no cure. He wants to inspire others, cancer patient or not, and make them believe that anything is possible, even in light of terminal illness.

Smith, who owns a graphic design and web firm in Athens, Ga., was diagnosed in December 2013 with stage 3B lung cancer, which means the disease had spread from his lungs onto the opposite side of his chest and into his lymph nodes. That stage of cancer has a 5 percent five-year survival rate, making it one of the deadliest cancers in the world.

Since his diagnosis, though, Smith has run countless 5Ks, 10Ks, half marathons, and sprint-distance races— thanks to a longtime interest in such physical pursuits, but also due to a targeted drug that blocks the genetic mutation that caused the disease. Smith has never smoked cigarettes, which causes nine out of 10 lung cancers, according to the Centers for Disease Control and Prevention.

“If you get cancer, it’s not automatically a death sentence, or that your-quality-of-life-is-going-to-crap sentence,” Smith told FoxNews.com. “That’s one of the biggest things for me: With targeted therapy, I’m able to do this, and my quality of life has changed very little.”

Smith is aiming to complete half of the PPD IRONMAN® North Carolina triathlon on Oct. 22, 2016, as part of team Free to Breathe, a Madison, Wisconsin-based lung cancer research and advocacy organization. A half Ironman, often referred to as an Ironman 70.3, involves about that many miles total: a 1.2-mile swim, a 56-mile bike ride, and a 13.1-mile run.

“If I see a guy who’s doing a half Ironman and know he has late-stage lung cancer, I would be inspired, but I also think I’d be, ‘That’s phenomenal— how has cancer treatment gotten to this stage that that could be done?” Smith said.

Smith’s oncologist Cynthia Shepherd, an internist at the University Cancer and Blood Center in Athens, Ga., said she considers him not only a patient but also a friend.

“Kirk is a special person to me,” Shepherd told FoxNews.com. “It’s just exciting to see him hopefully as the face of Free to Breathe to help educate others about the importance of research.”

Research led to the creation of the drug that’s sustaining Smith’s life.

He is part of the nearly 4 percent of Americans whose lung cancer stems from a genetic mutation. After undergoing genetic testing for about 200 mutations, he was diagnosed with ALK+ lung cancer, marked by an anaplastic lymphoma kinase genetic mutation.

“[Smith] was doing anything and is doing everything right in regards to exercise and eating right— and unfortunately, he still got lung cancer."

- Cynthia Shepherd, Kirk Smith's oncologist

He went to the emergency room after suffering from chest pain during a mild 30-minute run home from his office. Previous discomfort came and went during his runs, but when it felt more intense, he chalked it up to a pulled muscle. This time was worse.

“It hurt so much, I had to stop. It felt like someone was stabbing me,” he said.

Smith drove himself to the emergency room, at this point thinking a heart issue may have been the source of his pain. He didn’t have a family history of lung cancer, and none of his immediate relatives smoked.

A pulmonologist took a tissue sample and scheduled a bronchoscopy several days later. On Dec. 26, 2013, Smith was diagnosed with the disease— doctors found two tumors in his left lung, and the pain he’d been feeling was one pinching a portion of the organ and cutting off blood supply.

“That part of my lung is now toast,” Smith said. “If I hadn’t gotten it checked, I may have gotten to stage 4 [lung cancer],” which has an even worse survival rate, somewhere under 10 percent.

If Smith was diagnosed about a decade ago, doctors would have put him on a traditional cancer treatment regimen, with chemotherapy and radiation. But in 2007, scientists discovered the ALK mutation, following their identification of the EGFR and preceding the ROS1— two other genetic mutations linked with lung cancer. Doctors have noticed the ALK mutation usually affects people with Smith’s profile: men who have had little to no exposure to tobacco, and who are active and healthy.

“[Smith] was doing anything and is doing everything right in regards to exercise and eating right— and unfortunately, he still got lung cancer,” Shepherd said.

In 2011, the Food and Drug Administration (FDA) approved crizotinib, a drug developed to combat the ALK mutation. Smith took the drug from January to February 2014, and it halted his tumor from growing, but it also caused his liver enzymes to skyrocket to dangerous levels.

“If your liver can’t function, it can shut down and you can die of liver failure,” Shepherd said. “Even though [crizotinib] kills the cancer, it has this unique toxicity in the liver.”

Shepherd tried restarting Smith at a lower dose but eventually switched him to ceritinib in May 2014, which the FDA approved the month prior. Ceritinib blocks the proliferation of cancer cells caused by the genetic pathway and its corresponding resistance to apoptosis, or the body’s ability to kill cells, effectively eradicating the cells and halting their growth. Unlike chemotherapy and radiation, targeted drugs like ceritinib kill only cancer cells, not healthy cells.

Smith’s most recent CT scan— about two years after being on the drug— indicated clear lymph nodes and immeasurably small lung cancer tumors.

“This shows what a remarkable drug it is and the importance of finding this mutation in people like Kirk,” Shepherd said.

Although it’s uncertain whether Smith’s diet and exercise have made his medication more effective, Shepherd believes it’s apparent that his lifestyle has helped suppress some of the drug’s side effects, including nausea, diarrhea and vomiting.

Smith takes four pills a day, and usually if he takes one before he exercises, he doesn’t have those problems.

“Not only does exercise keep me healthy, but it helps my quality of life so I’m not at work with bowel issues,” Smith said.

"Obviously people look at him and feel inspired without even knowing what his situation is.”

- Ryan Marsh, Kirk Smith’s longtime friend and personal trainer

Ryan Marsh, a partner at Athens Personal Fitness in Athens, Ga., manages Smith’s diet and rigorous training regimen. He goes on steady-paced morning runs that range from 5 to 8 miles six days a week. In the afternoons or evenings, he’ll do strength training twice, and among the five other days he’ll do swimming, or mountain or road biking. On Sunday, though, Smith does a trail run in the morning, a two- to three-hour road ride, plus an afternoon swim.

“Since he’s been on this new drug, the main side effect is muscle cramping, and that’s just something almost a normal person would experience with some of the things he does,” said Marsh, 37, who as Smith’s accountability partner helps ensure he doesn’t over-exert himself. “But he seems to do a good job of dialing back the intensity when [the muscle cramps] come back.”

To support his physical activity, Smith consumes about 4,000 calories a day, including one or two protein-rich smoothies. Marsh said that intake has helped improve Smith’s immunity and achieve his fitness goals safely.

“One of the coolest things about Kirk is he is so encouraging,” said Marsh, who has been friends with Smith since 2008, before his diagnosis. “Obviously people look at him and feel inspired without even knowing what his situation is.”

Smith sees Shepherd for monthly checkups to ensure his liver enzymes aren’t too elevated and that his tumor is still suppressed. Targeted drugs like ceritinib are too new to know how much survival rates for patients like Smith have improved, but Shepherd said data indicate the drugs work for a few years.

“It would not be a shock for [Smith] to hear me say that eventually the cancer will start growing,” Shepherd said. “When, we don’t know. We wish we knew so we could catch it.”

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Alectinib, a third drug to block the ALK mutation, was FDA approved in December 2015, and that could be an option for Smith down the line, Shepherd said. Emerging immune checkpoint inhibitors, some of which have already been approved in lung cancer, and also result in few side effects, may also be a good medication for Smith. These drugs stimulate the immune system to attack cancer cells like a virus or bacterium.

“This has become a very important field in cancer treatment,” Shepherd said. “It could pertain to Kirk down the road.”

“We’ll run through the ALK inhibitors, and if those aren’t working for him, we’d move to these immune checkpoint inhibitors,” she said. “And we can do the chemotherapy, but obviously that has more side effects so the longer we can get him on these oral medications without side effects, the better.”

"I’m two and a half years into a late-stage lung cancer diagnosis, and I’m really lucky to be here."

- Kirk Smith

Smith pointed out that although lung cancer kills more people than prostate, breast and colon cancer combined, it’s the most underfunded cancer in research— in large part due to stigma surrounding smoking.

As he trains for his half Ironman, Smith hopes not only to raise awareness for lung cancer research but also to use himself as a “guinea pig”— trying to push himself personally as well as the perceived boundaries of cancer patients.

In his prime, he broke four hours and 30 minutes for a half Ironman. This time around, his goal is to complete the competition in less than five hours.

“I can’t make my lungs any bigger and make that part of my lung alive again, so what can I do to maximize what I have, and still be competitive, but still enjoy the fact that I’m still alive?” he said. “I’m two and a half years into a late-stage lung cancer diagnosis, and I’m really lucky to be here, so I don’t take any of this for granted.”