HPV Linked to Increased Risk of Lung Cancer in Smokers

Human papillomavirus, or HPV, is the most common sexually transmitted infection in the United States. It has long been known to cause cancers of the sex organs, especially the cervix, and recent studies have found connections between HPV and cancers of the mouth and throat. New research suggests it also compounds the risk of developing lung cancer for smokers.

Dr. Arash Rezazadeh and colleagues from the University of Louisville in Kentucky found evidence of HPV in samples of tissue taken from lung cancer patients, all smokers. Out of 23 samples, six samples tested positive for HPV; although one case was later shown to be a cervical cancer that had spread to the lungs. The remaining five samples consisted of HPV-16, HPV-11, and HPV-22 strains. The study authors said smoking remains the most important factor in the development of lung cancer but “the fact that five out of 22 non-small-cell lung cancer samples were HPV-positive supports the assumption that HPV contributes to the development of non-small-cell lung cancer (NSCLC).” The study findings were presented at the First European Lung Cancer Conference in Geneva.

While Dr. Rezazadeh admits that their findings are “pretty controversial” and that future studies are needed, he also feels “it’s important to know that being infected with HPV does appear to increase lung cancer risk.” Dr. Lauren F. Streicher, an OB/GYN and professor at Northwestern Medical School said, “Though the study is the first to note the combined effects of smoking and HPV on the lungs, doctors have known for a while that women who smoke and contract HPV are more likely to develop cervical cancer than nonsmokers. Smoking plays a key role in the rate of conversion to malignancy in cervical cancer too.”

Although the study doesn’t discuss the possibility that the HPV vaccine presently available could also be effective in treating lung cancer, the implication is there. The Gardasil vaccine, introduced in the U.S. in 2006 to protect women against cervical cancer targets the same cancer-causing type of HPV found in the lung cancer samples, type 16. “As more of these studies are completed, we’re learning that the vaccine would clearly be preventive in many different kinds of cancer, not just cervical,” said Dr. Streicher.

According to the Centers for Disease Control and Prevention, 20 million Americans are presently infected with HPV, and another 6.2 million become newly infected each year. And the American Cancer Society estimates that in 2008, 11,070 women will be diagnosed with cervical cancer in the United States. Meanwhile, more than 161,000 Americans will die from lung cancer.