DENVER — Lung cancer rates are increasing in people who have never smoked, according to two new studies presented here at the 16th World Conference on Lung Cancer.

In fact, at one institution, the incidence of never-smokers diagnosed with non-small-cell lung cancer (NSCLC) jumped from 13% to 28% during a 6-year period, Eric Lim, MD, from the Royal Brompton & Harefield NHS Foundation Trust in London, United Kingdom, and colleagues report in their study. And many of these patients initially presented with advanced-stage disease.

The second study demonstrated that the incidence of lung cancer in never-smokers is increasing in the United States. This was observed in three facilities, most significantly for NSCLC. At one institution, for example, the rate of never-smokers climbed from 8.9% in 1990–1995 to 19.5% in 2011–2013.

“When we think of lung cancer, we think of smoking,” Dr Lim noted. But antismoking strategies implemented in the early 1980s have led to a decrease in smoking-related lung cancer.

Instead, “what we are seeing is an increase in the incidence of nonsmoking-related lung cancer,” he explained during a press briefing. “We have seen more than double the amount of patients coming to us.”

Annual Incidence Doubles

For their study, Dr Lim and his colleagues retrospectively analyzed data from a prospectively collected database of patients treated at their institution.

Of the 2170 patients who underwent lung cancer surgery from March 2008 to November 2014, 436 (20%) patients were never-smokers. The median age at presentation was 60 years, and 67% of the patients were women.

The annual increase in the incidence of never-smokers developing lung cancer rose from 13% in 2008 to 15%, 18%, 19%, 20%, and 28% in the subsequent years of the study, respectively. This was attributable to an absolute increase in number, not to a change in the ratio of never-smokers to current and exsmokers.

The most common histologic types of disease were adenocarcinoma (54%) and carcinoid (27%).

Early detection is important but challenging in this population, Dr Lim noted.

In this study, 52% of patients had no clear symptoms. Specific symptoms, such as hemoptysis, were experienced by only 11% of patients, and nonspecific symptoms, such as chest infection, were experienced by 18%. Cough was a presenting symptom in 34% of patients, and incidental imaging detected lung cancer in 36%.

“Clearly, it is not going to be cost-effective to screen the entire population of nonsmokers for lung cancer,” Dr Lim pointed out. Instead, because this group of patients does not have established risk factors, research on early detection — ideally by noninvasive or molecular screening — is urgently needed to identify early lung cancer in nonsmokers, he added.

Lung Cancer Rates Surging in Never-Smokers. Medscape. Sep 09, 2015.