What's Age Got to Do With Lung Cancer?

Cancer of any sort is typically thought of as a disease of aging, meaning that the older you are, the higher your chances of developing it. The National Cancer Institute reports that "advancing age is the most important risk factor for cancer overall, and for many individual cancer types," and that "the median age of a cancer diagnosis is 66 years. This means that half of cancer cases occur in people below this age and half in people above this age." Additionally, 25 percent of new cancer cases occur in people ages 65 to 74.

For lung cancer specifically, which represents 13.5 percent of all new cancer cases -- a projected 234,030 new diagnoses in 2018 -- the age statistics skew slightly older. The NCI reports that "lung and bronchus cancer is most frequently diagnosed among people aged 65-74" and that the median age at diagnosis is 70. A mere 8.6 percent of lung cancers are diagnosed in people younger than age 55.

[See: 7 Things You Didn't Know About Lung Cancer.]

Cancer tends to impact older people more because "at the cellular level, the older you get, the less effective your DNA repair mechanisms become and the more cumulative exposure you have to environmental toxins, carcinogens, etc. So it's a cumulative trauma over time that occurs," says Dr. Bryan Stanifer, a thoracic surgeon and director of the Women's Lung and Health Center at NewYork-Presbyterian/Columbia University Medical Center. Simultaneously, "there's a steady accumulation of random mutations that can also lead to cancer. So, it's just sort of a breakdown of your repair mechanisms, exposure time and randomness that accumulates over time" that can lead to the development of most any kind of cancer.

Because many patients are older at the time of diagnosis for lung cancer, this may impact whether or how the disease is treated. "Age is an important factor, but it's not everything and it's not the most important factor," says Dr. Humberto Choi, a pulmonologist at the Cleveland Clinic in Ohio. Treatment for lung cancer may include chemotherapy, surgery, radiation, immunotherapies or some combination of some or all of these treatment modalities, and sometimes, older patients are offered different approaches than younger ones."The reason that older people may be evaluated in a different way [to younger patients] is because at that in point in life, they'll commonly have other diseases. Some are related to smoking and some that are not," Choi says, adding that it's "very common for someone with lung cancer to have COPD and heart disease." These comorbidities may make it more difficult to tolerate intense treatments such as chemotherapy, "so we have to take those comorbidities into consideration. A lot of times, it's not the age itself," but being older means you're more likely to have other, complicating medical conditions, he says.

Dr. David P. Carbone, director of the Thoracic Center and professor of medicine at the Ohio State University James Cancer Hospital in Columbus, agrees that age is mostly a number and a patient's condition is a far more important factor in whether and how lung cancer is treated. "What I've learned in my experience is that it's not so much age as [the patient's] physical condition and other organ failures that they might have. I have seen 90-year-old patients that look healthier than some 50-year-old patients, so generally we try to tailor therapies based on objective measurements of how well their lungs work, how well their kidneys work, how well their heart works, those kinds of things."

[See: What Not to Say to Someone With Lung Cancer.]

Stanifer says concern over how side effects of treatment will be tolerated may dissuade some patients from forging ahead. "Traditional chemotherapy is toxic to everything," not just cancer cells. "Any cell that's dividing on a frequent basis is affected," which causes hallmark chemo side effects like hair loss, nausea and vomiting. "It's just not a targeted treatment, so when it affects everything, you get all these terrible side effects."

Patient preference may also factor into what happens after diagnosis, Choi says. "In some older patients who are in their 80s and 90s, sometimes it's their choice not to pursue treatment. Not all lung cancers are very aggressive -- some can have a very indolent course," and treatment might not make sense because the patient may be more likely to die of a comorbidity before the lung cancer kills them. So the decision of whether or not to treat a patient with lung cancer can become complicated.

Nevertheless, Carbone says doctors need to look at the risk versus benefit in treating any patient. "It is true that with any medical intervention -- the risks of the intervention have to be calculated in possible life years saved," so older, more fragile patients may not be well enough to undergo surgery or may struggle to tolerate the side effects of chemotherapy, which can be intense.

However, Stanifer says the arrival of newer immunotherapies means more patients who may not have been well enough for traditional treatments like surgery or chemotherapy in the past may have more options now. "If patients are found to have a mutation that we have targeted therapies for, those are so much better tolerated. Most of those are oral medications that patients can take on their own at home. So a lot of times we'll go that route." He cites an example of a 100-year-old patient who'd just been diagnosed with lung cancer, "so the debate is 'what should we do?' In that particular scenario, we don't yet have the molecular markers which tell us whether there's these targeted immunotherapies that we can give, but that's our initial plan." For example, patients who have an EGFR mutation, might be able to "avoid traditional chemotherapy, radiation and even likely surgery," and still be treated for the cancer. (Patients with EGFR mutations have more receptors for the protein called epidermal growth factor, which helps cells grow and divide. These receptors can be exploited by certain drugs to kill the cancer.)

Immunotherapies tend to have far fewer side effects in most patients, and advances in how these drugs are used and better targeting of the right patient populations for these therapies means that some patients may be able to avoid many of the worst side effects.

Although lung cancer tends to affect older patients more, there is one subset of patients who have a tendency to develop lung cancer at younger ages: women. Stanifer says that 85 percent of all patients who develop non-small cell lung cancer were smokers, and "just under half of those are women." But among the 15 percent of NSCLC cases that occur in nonsmokers, "two-thirds of those patients are women, and nobody knows why. If you're talking about lung cancer overall, in all-comers, it's about 55 percent male, 45 percent female and the median age at diagnosis is 70. But if you start looking at nonsmokers and patients who are less than 60 years old, it's a majority women."

Stanifer and his team at Columbia are researching why this is the case. Current theories range from hormonal differences between men and women and whether women have a higher exposure to an environmental carcinogen that men tend to avoid somehow. "But the ultimate answer is that no one knows right now."

[See: 7 Innovations in Cancer Therapy.]

No matter your age or sex, smoking is still far and away the No. 1 risk factor for developing lung cancer of any type at any age, but you can change your risk profile by quitting. "If you're actively smoking, stop. That's by far the biggest modifiable risk factor that we know of," Stanifer says. And, "if you're at an elevated risk because you were an active smoker and you're older, the best thing you can do is go get lung cancer screening." Lung cancer screening involves a low-dose CT scan of the lungs that creates an image of the lungs, which can show lesions. CT scanning is more powerful than X-rays, but frequently results in false positives. These false positives may result in unnecessary procedures such as biopsies and surgery that cause harm to the patient.

Although screening can be a double-edge sword and not everyone will qualify for it, Stanifer says one trial "reported in 2011 in the New England Journal of Medicine showed a 20 percent reduction in lung cancer--related mortality in patients who were screened. If that were a chemotherapy, that would have been on the cover of every newspaper around the world." Talk to your doctor about your risk for lung cancer and whether screening is a good idea for you.

Elaine K. Howley is a freelance Health reporter at U.S. News. An award-winning writer specializing in health, fitness, sports and history, her work has appeared in numerous print and online publications, including AARP.org, espnW, SWIMMER magazine and Atlas Obscura. She's also a world-record holding marathon swimmer with a passion for animals and beer. Contact her via her website: elainekhowley.com.