EPIDEMIOLOGY AND AETIOLOGY OF LUNG CANCER Francesco Petrella, MD Deputy Director Division of Thoracic Surgery European Institute of Oncology Milan, Italy 1

MOST FREQUENT CANCERS WORLDWIDE Rank Male Female Both Sex 1 Lung Breast 2 Prostate Colorectum 3 4 Stomach Cervix of uterus 5 Liver 2

MOST COMMON CAUSES OF CANCER DEATH WORLDWIDE Rank Male Female Both Sex 1 Lung Breast 2 Liver 3 Stomach Colorectum 4 Cervix of uterus 5 Prostate 3

2015 FORECAST 4

LUNG CANCER IN THE WORLD The differences in lung cancer epidemiology between males and females can be largely explained by the disparity between the history of smoking habits of the two genders In fact, the majority of lung cancer cases (80%) can be firmly attributed to tobacco smoking 5

INCIDENCE AND MORTALITY FOR LUNG CANCER IN EUROPE 6

RISK FACTORS Although tobacco smoking is the main risk factor for lung cancer, an estimamted 10% - 25% of lung cancer cases worldwide occur in “never-smokers” “Never-smokers”: individuals who have smoked < 100 cigarettes in their lifetime “Heavy-smokers”: individuals who have smoked 20 pieces a day for 20 years 7

SMOKING 1950’s Wynder & Graham – USA: 604 patients with diagnosed lung cancer divided in “moderate” and “heavy” smokers + control group of cancer-free hospitalized individuals 1) the prevalence of lung cancer was rare among non-smokers 2) among patients with lung cancer, tobacco use tended to be higher 3) the prevalence of lung cancer among males and females matched their smoking patterns 4) the enormous increase in the sale of cigarettes in the US paralleled the increase in lung cancer 8

SMOKING 1951 the British Doctors Study: prospective cohort study among 40,701 British physicians, followed up for 50 years (until 2001 !!) 1,052 deaths due to lung cancer in a 50 years follow up period Results: lung cancer mortality was confirmed to be closely related to continued cigarette smoking and to the daily number of cigarettes smoked 9

MORTALITY FOR LUNG CANCER BY SMOKING HABIT 10

QUITTING SMOKING A lifelong male smoker has a cumulative risk of 15.9% for dying from lung cancer by age 75 The cumulative risk of dying from lung cancer for men who cease smoking at ages 60,50,40 and 30 years falls to 9.9%, 6%, 3% and 1.7% respectively Therefore, smoking cessation, in both sexes and at any age, should be strongly encouraged 11

SECOND-HAND SMOKING Exposure to other people smoking is associated with an increased risk of lung cancer Second-hand smoking or “environmental tobacco smoke” – “passive smoking” – “forced smoking” has been designated as a known human carcinogen by the International Agency for Research on Cancer It is a mixture of sidestream smoke (from the burning tip of a cigarette, cigar or pipe) and mainstream smoke (exhaled by smokers) 12

SECOND-HAND SMOKING It is particularly disappointing because it damages people who have chosen not to smoke and are involuntarily exposed to the risk factors (children!!) The levels of exposure to second-hand smoke in public spaces can be influenced substantially by the adoption of comprehensive smoke-free legislation 13

AIR POLLUTION There is a statistically significant association between lung cancer and ambient level of particulate matter with diameter less of 10 micro/m The levels of particulate matter seem to associated with the increase in the risk of lung adenocarcinoma In October 2013, the International Agency for Research on Cancer classified outdoor air pollution as carcinogenic to humans 14

AIR POLLUTION A reduction in particulate matter air pollution could contribute to reduce the incidence of lung cancer The increase in individual risk of lung cancer determined by exposition to air pollution is far lower than the risk determined by tobacco smoking 15

EXPOSURE TO RADON Exposure to radon and its inhalation is responsible for 9% of deaths from lung cancer and 2% of all deaths from cancer in Europe When inhaled, radon is mostly exhaled immediately, but its solid progeny tend to be deposited on the bronchial epithelium, with a subsequent emission of alpha particles and irradiation of bronchial cells 16

EXPOSURE TO RADON Radon was identified as a risk factor for developing lung cancer when a high incidence rate of this disease was described in underground uranium miners In most houses concentration of radon is low, but in some it is much higher then the acceptable level 17

EXPOSURE TO RADON Most radon-related deaths are not caused by the very high radon concentrations present in a small minority of cases, but are caused by exposure to moderate concentrations Policies requiring basic preventive measures against radon in all new buildings could avoid a substantial proportion of radon-related lung cancers and have been suggested to be highly cost-effective 18

DIET AND RISK OF LUNG CANCER In contrast to other malignant tumours – especially those of the gastrointestinal tract – the association between diet and risk of lung cancer is not very strong The risk of squamous cell carcinoma in current smokers seems to be reduced by an increase of 100 g/day of fruit and vegetables consumption The relationship between diet patterns and risk of lung cancer is poorly understood 19

“It is not in the stars to hold our destiny but in ourselves” William Shakespeare The tragedy of Julius Caesar, 1599 20

Francesco Petrella francesco.petrella@ieo.it 21