NewsAwareness
World No Tobacco Day: The Single Biggest Preventable Cause of Cancer
Every May 31, World No Tobacco Day highlights the harms of tobacco. Here is a calm, NCI-based look at the link between tobacco and cancer — and the benefits of quitting.
A plain-language summary based on public reporting and trusted sources, linked below.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
Where the date came from
WHO member states created World No Tobacco Day in 1987. The first version was a world no-smoking day on 7 April 1988, set by World Health Assembly Resolution WHA40.38. A second resolution the following year, WHA42.19, moved it to 31 May and made it annual.
That is not trivia. It means the observance was written by governments, not by a charity, and it sits alongside binding treaty work rather than beside it.
What is in the smoke
NCI counts the chemicals. Tobacco smoke contains more than 7,000 of them. At least 250 are known to be harmful, including hydrogen cyanide, carbon monoxide and ammonia.
Of those 250, at least 69 can cause cancer. NCI names arsenic, benzene, cadmium, chromium, formaldehyde, nickel, vinyl chloride, polonium-210 and the tobacco-specific nitrosamines among them.
Polonium-210 is worth pausing on. It is a radioactive element, and it arrives in the smoke.
The list of cancers is longer than people think
Most people connect tobacco with lung cancer and stop there. NCI's list is far wider.
Tobacco use causes cancer of the lung, larynx, mouth, esophagus, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum, and cervix. It also causes acute myeloid leukemia, a cancer of the blood.
Smokeless tobacco, meaning snuff or chewing tobacco, is not a safe substitute. NCI says people who use it have increased risks of cancers of the mouth, esophagus and pancreas. Our page on smokeless tobacco covers it.
NCI is blunt about the general rule. There is no safe level of tobacco use.
The scale
WHO's tobacco fact sheet puts numbers on it. Tobacco kills more than 7 million people each year, including over 1.6 million non-smokers exposed to secondhand smoke. It is a risk factor for more than 20 different types or subtypes of cancer.
Around 80 percent of the world's 1.2 billion tobacco users live in low- and middle-income countries, where the burden of illness and death falls heaviest.
In the United States alone, NCI reports that cigarette smoking and exposure to tobacco smoke cause about 480,000 premature deaths each year. Of those, about 36 percent are from cancer, 39 percent from heart disease and stroke, and 24 percent from lung disease.
What quitting buys, by age
This is the part with the most useful arithmetic in it, and NCI publishes it plainly.
People who quit between the ages of 25 and 34 live about 10 years longer than those who keep going. Quitting between 35 and 44 adds about 9 years. Between 45 and 54, about 6. Between 55 and 64, about 4.
People who quit before age 40 reduce their chance of dying early from a smoking-related disease by about 90 percent. Those who quit between 45 and 54 cut it by about two-thirds.
And in a study following people aged 70 and older, even those who quit in their 60s had a lower risk of death during follow-up than those who continued.
NCI also notes that quitting at the time of a cancer diagnosis reduces the risk of death. That one matters, because it is the moment people most often assume it is too late.
Our page on quitting smoking covers the methods and medicines that help.
When to get checked
Two things are worth acting on, and they are separate.
Screening. The U.S. Preventive Services Task Force recommends a yearly low-dose CT scan for adults aged 50 to 80 with a 20 pack-year smoking history who smoke now or quit within the past 15 years. A pack-year means one pack a day for a year. Our guide to lung cancer screening explains the visit.
Symptoms. NCI says lung cancer sometimes causes nothing at all and is found on a scan done for another reason. When it does show itself, check with a doctor for chest pain, a cough that persists or worsens, trouble breathing or wheezing, blood in sputum, hoarseness or trouble swallowing, loss of appetite, unexplained weight loss, fatigue, or swelling in the face and the veins of the neck.
That last one is urgent rather than routine. It can mean a tumor is pressing on the large vein returning blood to the heart.
For other tobacco-linked cancers, the symptoms differ by site: blood in the urine for bladder, a mouth sore or patch that will not heal, a swallowing problem that persists.
What this does not mean
Quitting does not return risk to that of someone who never smoked. It lowers it substantially, and it keeps lowering it over years, but the line does not fully close.
A day on a calendar does not do anything on its own. WHO's own framing includes the business practices of tobacco companies, not just individual choices, which is a reminder that this is a policy problem as much as a personal one.
And nicotine on its own is not harmless. WHO notes it is highly addictive and affects brain development in adolescents and young adults, including attention and learning, and that it raises cardiovascular risk.
Our pages on tobacco and cancer and secondhand smoke cover both sides of that.
NCI runs a free, confidential quitline at 1-877-44U-QUIT, which is 1-877-448-7848, Monday to Friday, 9:00 a.m. to 9:00 p.m. Eastern time.
Sources
- WHO, World No Tobacco Day (campaign page) — https://www.who.int/campaigns/world-no-tobacco-day
- WHO, Tobacco fact sheet — https://www.who.int/news-room/fact-sheets/detail/tobacco
- NCI, Tobacco — https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco
- NCI, Harms of Cigarette Smoking and Health Benefits of Quitting — https://www.cancer.gov/about-cancer/causes-prevention/risk/tobacco/cessation-fact-sheet
- NCI PDQ, Non-Small Cell Lung Cancer Treatment (Patient Version) — https://www.cancer.gov/types/lung/patient/non-small-cell-lung-treatment-pdq
- USPSTF, Lung Cancer: Screening — https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/lung-cancer-screening
How this article was prepared
An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.
The National Cancer Information Foundation publishes Cancer Explained. This page is for learning. It is not medical advice and does not suggest a test or treatment.
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Put the story in context
Prevention, possible warning signs, screening, and diagnosis
This story relates to Tobacco and cancer. The information below is general: it does not reveal anything else about a public person’s health, and not every point applies to every cancer. Personal advice depends on age, symptoms, family history, exposures, and medical history.
Prevention and risk reduction
Not every cancer can be prevented. Avoiding tobacco, protecting skin from ultraviolet radiation, limiting alcohol, staying active, and receiving recommended HPV or hepatitis B vaccination can lower the risk of certain cancers. A risk factor is not a prediction or a cause in one individual.
Symptoms and possible early signs
Possible signs vary and are often caused by conditions other than cancer. Changes worth discussing include a new lump, unexplained bleeding or weight loss, a persistent cough, lasting bowel or bladder changes, a changing skin spot, or symptoms that persist or worsen. Some early cancers cause no symptoms.
Screening and early detection
Screening looks for certain cancers before symptoms begin. Recommended tests exist only for some cancers and depend on age and risk. Screening can have benefits and harms; it is not the same as evaluating a new symptom, and there is no single routine scan or blood test that reliably screens for every cancer.
How cancer is diagnosed
Diagnosis may involve a history and exam, imaging, laboratory tests, and often a biopsy. Pathology can identify the cancer type and may test biomarkers that guide treatment. Symptoms, screening results, tumor markers, or online stories alone cannot confirm cancer.
Learn about this story’s cancer topic
A public story may encourage questions, but it should not be used to estimate your risk or choose testing. Contact a healthcare professional about a persistent or concerning change. Seek urgent care for severe or rapidly worsening symptoms.