Lung cancer remains a challenge for oncologists, partly because it’s difficult to detect early. When doctors discover lung cancer late, survival rates plummet. That’s why physicians like surgeon Kemp Kernstine, M.D., Ph.D., director of City of Hope’s Lung Cancer and Thoracic Oncology Program, continually search for new and better ways to treat the disease — and give patients a fighting chance.
In the first of a two-part interview about lung cancer, Kernstine discusses the reasons behind the disease.
Kemp Kernstine (Photo by Kaminsky Productions)
eHope: We all know smoking is the major cause of lung cancer, but what else can bring it on?
Kemp Kernstine, M.D., Ph.D.: Exposure to cigarette smoke appears to account for 85 percent of primary lung cancer cases. The second most common cause of lung cancer appears to be radon exposure. Radon is a naturally occurring substance from the radioactive decay of uranium in the earth's crust. Poorly ventilated basements in homes are the most common source of exposure.
Another cause is asbestos exposure. We see this most often in shipyard workers, carpenters, electricians and bricklayers. Most believe that asbestos commonly causes mesothelioma. On the contrary, mesothelioma is fairly uncommon, and the more common result of asbestos exposure is lung cancer.
Chronic exposure to heavy metals, such as that seen in welders, increases the likelihood for lung cancer. And construction workers are exposed to vinyl chloride that may cause lung cancer.
There are a number of other inhaled substances and even infectious agents, such as viruses and combinations of different bacteria, that may be related to lung cancer, as well.
EH: Viruses and bacteria can cause lung cancer?
KK: Potentially. Certain retroviruses, the same general group as the AIDS virus, can cause lung cancer. Also, human papillomavirus (type II) causes recurrent respiratory papillomatosis, which can develop into squamous cell cancer of the lung. It is a serious problem for young patients. I have had several young patients, less than 30 years old and nonsmokers, with this affliction who died from lung cancer. Recently, however, we’ve been finding it in older patients, as well.
Another virus is called the John Cunningham virus. It infects 70 to 90 percent of the population and has recently been found to be associated with the development of lung cancer.
As for bacteria, we are not sure if it is certain specific bacteria or a combination. Or maybe it is the resulting inflammatory response caused by bacteria. Researchers are still looking for the answer.
EH: How big a factor is air pollution? Should we all be thinking about moving to the country?
KK: There may be a role for air pollution as a cause for lung cancer. However, it appears minimal. Some studies have shown that patients who live in heavily industrial areas have a greater likelihood for the development of lung cancer compared to those who do not. But for most cities, such as Los Angeles, the risk is small at best. Moving to the country may have other benefits to health, but the reduction in lung cancer development is likely not one of them.
Check back into the December issue of eHope to hear more from Kernstine about lung cancer treatment and the push to save more lives of those diagnosed with the disease.