holds the dubious distinction of being the #1 cancer killer of both men and women. The widely held assumption that lung cancer is caused by smoking is fairly accurate: 85 percent of cases are smoking induced. But 15 percent of lung cancers are not related to smoking, and this is of great interest to Loretta Erhunmwunsee, M.D.
, assistant professor in City of Hope’s Division of Thoracic Surgery
While in residency at Duke University, Erhunmwunsee found the team approach to surgery — and thoracic surgery in particular — appealing. She was also drawn to oncology, so a commitment to treating cancers of the thorax was a natural fit.
You have a particular interest in treating lung cancer unrelated to smoking. What’s the root of that focus?
Most patients I’ve come in contact with in fact do smoke. But in Los Angeles a lot of patients aren’t smokers. This was very different from my experience in North Carolina, where I trained for 10 years.
The diagnosis of breast cancer is devastating for most but each woman knows she’s at risk because she has breast tissue. But those who do not smoke are typically shocked when they find out they have lung cancer because everyone associates lung cancer with smoking. The first question is, how did I get this? And what’s next? And that’s what we’re trying to figure out.
In your experience, is there a deeper level of disbelief and even resentment among nonsmokers who receive a lung cancer diagnosis?
No, not really. By the time they meet with me, they’ve typically already been diagnosed, so what I’ve noticed is a resolve: What are we going to do about this now? By that point, cancer is cancer and they want to treat it and move on.
More women than men fall into the category of nonsmokers with lung cancer. Do you have any explanation for this?
So far, the data is not clear. Are there hormonal factors? Environmental factors? Asian women, in particular, are more prone to developing non-smoking–related lung cancer. This may be related to certain cultures using cooking methods that produce indoor air pollution but this is certainly not the only factor and may not be the most important in this group.
Do smokers and nonsmokers present with different types of lung cancer?
For both smokers and nonsmokers, the majority of patients, 85 percent, have non-small cell lung cancer (NSCLC). The other main type is small cell lung cancer, which overwhelmingly occurs in people who have smoked a lot. NSCLC comprises three histologic (tissue) subtypes: adenocarcinoma, which is more common in nonsmokers; squamous cell carcinoma, which occurs more frequently in smokers; and large cell cancer, which is rare in either group.
What about treatment? Does it differ based on whether someone is a smoker or nonsmoker?
No, the treatment approach is the same. However, we do so much molecular analyses now, and what we know is that a never-smoked lung cancer looks very different from a smoker’s lung cancer. Based on this genetic information, immunotherapy is sometimes an option. We’re pushing the envelope and looking at genetic changes and trying to determine whether this therapy works for each individual patient.
What is your role in the treatment plan?
Unfortunately, by the time most patients receive a diagnosis, they have advanced disease. So, for most patients, surgery isn’t the answer. But in patients whose cancer is stage 1 (localized in the lung) or 2 (in the lung and possibly in the nearby lymph nodes), resection of the tumor would be appropriate. In more advanced disease, I might be called in to perform surgery after the patient has received chemotherapy to shrink the tumor, to make surgery more viable.
Can you address the possible role of environmental factors, such as asbestos or radon exposure, in the development of lung cancer in nonsmokers?
Most of our known asbestos–related patients have mesothelioma
(cancer of the lining of the lungs, abdomen or heart). It's hard to tease out the environmental factors attributable to lung cancer cases. We don't typically know that a patient got lung cancer from the environment; we just have data indicating the high risk of these factors.
Are there any preventive measures a nonsmoker can take to avoid developing lung cancer? For example, are there any genetic markers that could reveal something useful?
I’m in the process of assembling a research team that will examine different social determinants, such as income and education, of lung cancer in women who’ve never smoked to determine if those factors impact the development of the disease.
Other studies are trying to determine whether people are predisposed, but currently there are no genetic markers that can be found early and subsequently prevent lung cancer. To date, the best way to prevent lung cancer is to abstain from smoking. Those who smoke or have previously smoked heavily should be screened with an annual CT, which improves the survival rate by twenty percent.