Lung cancer remains the world's deadliest cancer

Every year since 2012, the 1^er August marks World Lung Cancer Day. A day dedicated to raising awareness of the problems associated with this cancer and emphasizing the need for increased funding for lung cancer research. Each year, 2,206,000 new cases of lung cancer are diagnosed worldwide, and it causes 1.8 million deaths.

Lung cancer begins in the bronchi and there are two main types: small cell and non-small cell. Smoking is by far the main risk factor for lung cancer, due to the exposure of the bronchi to carcinogenic substances in tobacco smoke, which causes a normal bronchial cell to transform into a cancerous cell that, by dividing, produces a tumor that develops in the chest and can then metastasize to distant sites.[1].

The deadliest cancer in the world and in France

In 2020, lung cancer was the leading cause of cancer death worldwide with approximately 1.8 million deaths (18%), followed in order of frequency by colorectal cancer (9.4%), liver cancer (8.3%), stomach cancer (7.7%) and female breast cancer (6.9%). Unfortunately, despite continued improvements in treatments, the prognosis for lung cancer patients remains poor with a 5-year survival rate of around 25 % for non-small cell cancers and 7 % for small cell cancers, according to the American Cancer Society[2].

In France, lung cancer is the leading cause of cancer-related death, accounting for 33,000 deaths annually; it is the third most common cancer, with 46,363 new cases diagnosed in 2018 (in 31,231 men and 15,132 women). The incidence of this cancer is increasing rapidly among women in France, with 411 cases occurring in women under the age of 50.

According to the report "Global Cancer Statistics 2020"[3] According to the American Cancer Society and the International Agency for Research on Cancer (IARC), approximately 28.4 million new cases of cancer are expected to occur worldwide in 2040, an increase of 47% from 2020.

Smoking, the main risk factor for lung cancer

Smokers are up to 22 times more likely to develop lung cancer during their lifetime than non-smokers[4]This risk increases much more with the number of years of smoking than with the total amount of tobacco smoked. Also, smoking a few cigarettes a day becomes a considerable risk if this consumption extends over years. Nonsmokers exposed to secondhand smoke at home, at work, or in other public places have an elevated risk of developing lung cancer.

Not smoking and avoiding secondhand smoke are the best ways to prevent lung cancer. The risk of lung cancer gradually decreases in the years following smoking cessation, so it is advisable to quit as soon as possible.

Smoking cessation should be an integral part of lung cancer treatment

While quitting smoking as early as possible remains the most effective way to prevent this cancer, it also provides health benefits for patients even after the disease is diagnosed. According to a study Italian published in the Journal of Thoracic Oncology[5], stopping smoking as soon as possible after diagnosis of lung cancer (at any stage of the disease) is associated with an improvement in overall survival of around 30%, compared to patients who did not stop smoking.

Keywords: Lung cancer, smoking, smoking cessation, withdrawal, mortality

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[1] National Committee against Smoking, Tobacco: specific risks for the respiratory system, accessed August 1, 2022

[2] American Cancer Society. Lung Cancer Survival Rates, updated January 29, 2021, accessed 1^er August 2022

[3] Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2021 Feb 4. https://doi.org/10.3322/caac.21660

[4] World Cancer Day: know the facts – tobacco and alcohol both cause cancer, WHO Regional Office for Europe, accessed 1^er August 2022

[5] Caini S, Del Riccio M, Vettori V, Scotti V, Martinoli C, Raimondi S, Cammarata G, Palli D, Banini M, Masala G, Gandini S, Quitting smoking at or around diagnosis improves the overall survival of lung cancer patients: a systematic review and meta-analysis, Journal of Thoracic Oncology (2022), doi: https://doi.org/10.1016/j.jtho.2021.12.005.