A new study has identified significant differences between lung cancer patients who smoke and those who don't.
Smoking is the main risk factor for non-small cell lung cancer, but nonsmokers can get it too and rates of the disease among nonsmokers are rising in many countries, according to researchers at the Portuguese Institute of Oncology in Lisbon.
The investigators compared more than 1,400 Portuguese patients with this type of lung cancer and found that nonsmokers were more likely than smokers to be women and to have adenocarcinoma, the most common form of non-small cell lung cancer.
The nonsmokers were also less likely to have chronic obstructive pulmonary disease (COPD), heart disease, previous cancer of the larynx, or weight loss, the results showed.
In addition, nonsmokers lived about twice as long after diagnosis, an average of 51 months compared to 25 months for smokers, according to the study presented Sunday at a meeting of the European Respiratory Society in Amsterdam, the Netherlands. Studies presented at medical meetings are typically considered preliminary, because they are not subject to the same rigorous review as published studies.
"Because lung cancer represents a set of tumors with confounding and sometimes misleading symptoms in both smokers and nonsmokers, we felt that it was of particular importance to acquire this knowledge," study author Dr. Catia Saraiva said in a European Lung Foundation news release.
"We believe that the differences we found between the two groups will help improve diagnosis, and prompt investigators to try to find out why these differences occur," she added.
Further investigation is needed to learn more about differences between smoking and nonsmoking lung cancer patients, the researchers said.
"In the nonsmoking group, we found professional exposure to carcinogens in 9 percent, a family history of lung cancer in 5 percent, and a previous cancer diagnosis in 6 percent. Additionally, 18 percent had high blood pressure," Saraiva said.
Many of the nonsmokers were diagnosed at an advanced stage of lung cancer, including 59 percent at stage four, when the cancer had already spread to other parts of the body, the study found.
