When someone is diagnosed with lung cancer, that person’s smoking habits often are scrutinized by family, friends, and acquaintances.
While smoking tobacco remains the leading cause of lung cancer in the United States — responsible for 80% to 90% of related deaths — 10% to 20% of lung cancer patients have never smoked, according to the Centers for Disease Control and Prevention (CDC).
Between 20,000 and 40,000 never-smoking Americans are diagnosed with lung cancer each year.
“And we’re probably underestimating that number,” says Liza C. Villaruz, MD, a medical oncologist and hematologist at UPMC Hillman Cancer Center specializing in treating lung cancer. “There are patients who smoke and get lung cancer not related to smoking, just like there are patients who drink but get liver failure from a virus.”
Dr. Villaruz is an associate professor of medicine at the University of Pittsburgh and a clinical and translational investigator in lung cancer with a focus on early drug development.
‘Never-Smoking’ Lung Cancer: Understanding Risk Factors
Never-smoking lung cancer would be one of the top 10 most common cancers in the United States if researchers separated these cases from smoking-related ones, Dr. Villaruz says.
Roughly 60% to 70% of never-smokers diagnosed with the disease have a type of non-small cell lung cancer (NSCLC) called adenocarcinomas. This type of cancer develops in the glands lining the organs.
Outside of cigarette smoke, a history of lung disease and environmental factors can increase lung cancer risk. According to the American Lung Association, these include exposures to substances such as:
- Air pollution
- Asbestos
- Radon gas
Radon is the leading cause of lung cancer among nonsmokers, the United States Environmental Protection Agency (EPA) estimates.
When the odorless, radioactive gas concentrates inside homes built on soil with natural uranium deposits, it can be deadly. The Pennsylvania Department of Environmental Protection estimates that roughly 40% of Pennsylvania homes have radon levels above the EPA action guidelines.
Never-smoking lung cancer patients are more likely to present symptoms, Dr. Villaruz says. That’s because they are often screened later than high-risk smokers.
“In smokers, we have CT scans, so it can be detected at an earlier stage,” she says. “The symptoms we associate with more advanced lung cancer, like cough, shortness of breath, chest pain, and weight loss, are usually more common in advanced cancer. CT screenings are not approved for never-smokers, and it’s tough because we’d essentially have to screen the entire population.”
Screening and Treatment for Lung Cancer in Non-Tobacco Users
Lung cancer screenings with low-dose computed tomography scans are currently recommended for people who fit all three of these criteria:
- They are 50 to 80 years old.
- They currently smoke or quit smoking in the last 15 years.
- They have at least a 20-pack-year history of smoking.
A pack-year is calculated by multiplying the number of packs a person smokes per day by the number of years they’ve smoked. A 20-pack-year history could be smoking one pack of cigarettes a day for 20 years, two packs a day for 10 years, or any other equivalent.
There are currently no recommendations for lung cancer screenings in nonsmokers. That’s because the risks associated with low-dose CT scanning may outweigh the benefits for those less likely to develop lung cancer.
“For a relatively common cancer, we don’t have good ways of detecting it in never-smokers,” Dr. Villaruz says.
Lung cancer patients have a variety of treatment options available at UPMC Hillman Cancer Center, including tumor removal, radiation, anticancer drugs, and other targeted therapies.
Patients may undergo surgery, chemotherapy, and targeted gene therapy to address tumor mutations found in lung cancer patients who have never smoked. These anticancer drugs can lengthen a person’s chance of survival by years, says Dr. Villaruz.
“Some of these patients can do much better than your average lung cancer patient with targeted therapies,” she says. “The tumors are generally less complex, meaning they don’t have as many mutations as smoking-associated lung cancers.”
This is especially crucial for people with advanced lung cancer that has spread, he says.
“Thirty-five percent of our patients with metastatic lung cancer will need targeted therapy,” says Dr. Villaruz. “With these, they can expect the tumor to shrink, and sometimes it won’t progress for years. In fact, we have a particular type of lung cancer called ALK-positive NSCLC where the five-year overall survival rate is 62%.”
For perspective, Dr. Villaruz says the average median survival rate for someone with metastatic lung cancer is 12 to 14 months.
“So, finding these genetic alterations and treating them appropriately can extend that by years,” she says.
For more information about lung cancer or UPMC Hillman Cancer Center, call 412-623-5864 or visit our website.
Editor's Note: This article was originally published on , and was last reviewed on .