[Relationship between primary lung cancer and tobacco consumption. Results of the KBP-2010-CPHG study by the French College of General Hospital Respiratory Physicians]

Introduction: The Collège des Pneumologues des Hôpitaux Généraux has performed a prospective multicentre epidemiological study which aims to describe the baseline characteristics of all new cases of primary lung cancer histologically or cytologically diagnosed in 2010 and followed-up in the respiratory department of general hospitals. The present publication compares the characteristics of these presentations according to their smoking history.

Methods: Seven thousand and fifty-one adult patients were included from 104 respiratory departments. A standardized form was completed at diagnosis and a steering committee checked the completeness of inclusion.

Results: Only 10.9% of patients were never-smokers and 89.1% ever-smokers (i.e., current or former smokers). Respectively, 3.7%, 10.7% and 85.6% of ever-smokers consumed/had consumed 1-10, 11-20, and >20 pack-years. Mean smoking duration was 37.5 years. Former smokers had stopped smoking on average 14.8 years previously. Only 20.7% of never-smokers reported that they had been exposed to tobacco smoke passively. At diagnosis, statistically significant differences were found between never- and ever-smokers (P<0.0001) for sex (women: 60.8% vs 18.8%), age (mean: 70.7 years vs 64.9 years), stage (IV: 70.8% vs 58.7%), histology (adenocarcinoma: 68.5% vs 42.6%), EGFR mutation exploration (51.4% vs 28.0%) and positivity (37.0% vs 4.6%). Differences between never- and ever-smokers rose with increasing tobacco consumption.

Conclusions: This study confirms that differences exist between never- and ever-smoker patients presenting with primary lung cancer and shows the impact of the level of tobacco consumption, in particular on histology.