New research has found that the number of non-smokers being diagnosed with non-small cell lung cancer has increased. The study, which will be presented today at the European Respiratory Society’s Annual Congress in Vienna, also discovered that the the number of women being diagnosed with this type of cancer is increasing as well.

Although the World Health Organization (WHO) confirmed earlier in the year that the inhalation of exhaust fumes from diesel engines can lead to lung cancer, scientists have little information on other potential risk factors that can cause lung cancer in non-smokers.

New drugs and new diagnostic techniques have greatly changed the management of lung cancer over the last ten years. A team of experts from the French College of General Hospital Respiratory Physicians set out to observe the effect of these changes and understand the prevalence and effects of lung cancer amongst the population.

The research consisted of 7,610 patients with lung cancer and 7,610 new cases of lung cancer in France in 2010 (6,083 were suffering with non-small cell lung cancer). The team used data from a similar study in 2000, which also investigated the characteristics of new cases of lung cancer.

Background information on each subject, including smoking history, age, the stage of their lung cancer at diagnosis, the histology of their cancer (scientists analyze tissue to understand variations in the disease), were gathered.

Results showed an increase in the number of women and non-smokers developing lung cancer:

  • 11.9% of the lung cancer cases in the study were non-smokers, which increased from 7.9% 10 years prior
  • 24.4% of lung cancer victims in the 2010 research were female, which increased from 16% in 2000

Analysis also showed that lung cancer rates barely changed for female smokers or former-smokers; from 64% in 2000 to 66% in 2010. This number had decreased in men, while the rate of male never-smokers increased.

A whopping 58% of patients in the study with lung cancer were diagnosed at stage 4, which is the most dangerous stage of the disease because it means the cancer has spread to both lungs or another part of their body. The authors suggest that a new classification of the different stages of the disease could be the reason for this high number, after seeing an increase of 15 percentage points from 43% in 2000.

The researchers also saw a change in the type of lung cancer with an increasing number of people developing adenocarcinoma (from 35.8% to 53.5%).

The findings show how lung cancer has changed over the last decade, lead author, Dr Chrystèle Locher, said. Not just has there been more women and more non-smokers developing the disease, but there also more cases diagnosed in stage 4 of the illness.

She concluded:

“We recently saw that the WHO have classified diesel fumes as carcinogenic, but more research is needed to understand other factors that could contribute to lung cancer in non-smokers. Anti-smoking campaigns must also target women more specifically, as we can see little change in lung cancer rates caused by smoking in women.

It is also important to note changes in the type of lung cancer. The prevalence of cases of adenocarcinoma lung cancer is growing and further research is needed to understand the characteristics of this form of the disease.”

Written by Sarah Glynn