Risk of Lung Cancer in Former Smokers

Former Smokers at Risk for Lung Cancer Decades Later

What is the risk of getting lung cancer after quitting smoking, and what should you know if you are a former smoker?

Lung Cancer Risk in Former Smokers

Many people are surprised to hear a true statistic about lung cancer: the majority of people who develop lung cancer in 2016 are non-smokers.  Some people have never smoked - and at least 20% of women who develop lung cancer are never smokers - but the majority of people diagnosed today are former smokers.

Lung cancer occurs more often in people who've already kicked the habit -- and that act of courage may have occurred well in the past.

Statistics on Former Smokers and Lung Cancer

It's pretty clear that former smokers are at risk of developing lung cancer, but how great is that risk?  How quickly does it decrease after you quit?  Once you've stopped, is your risk more like someone who continues to smoke, or someone who has never smoked?

Unfortunately, despite many studies on smoking and cancer we don't have many that address this as a function of risk over the duration of quitting.  Yet a 2011 study gives us a fairly good idea of risk over the long run.

 Researchers looked at over 600 people who were referred for lung cancer surgery and who were asked the question; "Did you smoke, and if so, when did you quit?"

Of these patients 77% had a history of smoking in the past, but only 11% were current smokers.

(Note, this is common.  The "average" patient had quit smoking 18 years before the diagnosis of lung cancer. The former smokers were broken down further by how long they had been "smoking abstinent":

  • 14% had been smoke free for less than a year
  • 27% were smoke free for 1 to 10 years
  • 21% were smoke free for 10 to 20 years
  • 16% were smoke free for 20 to 30 years
  • 11% were smoke free for 30 to 40 years
  • 10% were smoke free for 40 to 50 years

The conclusion was that the majority of patients in this group had been smoke free for more than a decade prior to their diagnosis of lung cancer. It is important to note that this was a group that was referred for surgical treatment of lung cancer, and as such, were likely in the earlier stages of the disease.

Importance of Alerting Former Smokers to This Risk

Lung cancer is most treatable in the early stages of the disease.  When it is discovered early, surgery can offer the chance of a cure.

So what does this mean for you personally?  What should you do if you quit smoking 10 years ago or 20 years ago?

That depends on how much you smoked and when you quit.  If you meet the criteria for screening, this is an excellent option.  If you don't?  Having an awareness of the symptoms of lung cancer could make the difference between finding your disease early, or finding it when it has already spread.  Yet even if you have screening, knowing the symptoms is important, as screening does not detect all cancers.

Knowing the symptoms seems easy, right?  Unfortunately, recent studies tell us that the majority of people are not familiar with the most common symptoms.

 Part of this is that lung cancer is changing.  The types of lung cancer most common in the past are different than the types most common today.  For example, forms of lung cancer such as squamous cell carcinoma of the lungs and small cell lung cancer used to be more common.  Those cancers tend to grow near the large airways of the lungs and cause symptoms early on - often a persistent cough or coughing up blood.

Today, lung adenocarcinoma is the most common type of lung cancer.  These cancers tend to grow in the outer regions of the lung, and not near the airways.  Symptoms are often a vague shortness of breath than many people disregard as being due to getting older or due to inactivity.

Lung Cancer Screening

Lung cancer screening is available for some people, and it's thought that using screening could decrease the death rate from lung cancer by 20% in the United States.  The current criteria includes those who:

  • Smoke or smoked for at least 30 pack years. (A pack year is calculated by multiplying the you smoked by the number of packages smoked per day.  For example, if you smoked 2 packs per day for 15 years, that would equal 30 pack years.)
  • Are between the ages of 55 and 80.
  • Continue to smoke or quit smoking in the last 10 years.
  • Are healthy enough to have surgery if an abnormality is found.

If You Smoked But Don't Meet the Criteria for Screening - Know the Symptoms

What if you smoked, but smoked for less than 30 pack years?  Or, what if you quit 12 years ago?  Studies are in progress looking to see if other people (beyond those who meet the criteria) would benefit from screening.  But what about you today?

For those who have other risk factors for lung cancer, such as a family history, it's important to talk to your doctor.  Some people may choose to have lung cancer screening even if they don't meet the smoking criteria.

For others, and even if you have screening, it's important to be aware of the early symptoms of lung cancer.  If you have any symptoms, make sure to talk to your doctor.  If you don't have an adequate explanation for your symptoms, ask for further studies or get a second opinion.  What we have been seeing repeatedly is that those who insist on an answer are often those who find it.    are finding    being your own advocate  

 

It's also important as we work to dispel the stigma of lung cancer. How many of us have tactlessly made a comment about smoking to someone newly diagnosed with lung cancer?

A High Five for Quitting

Part of me hesitated to write about this study. I don't want to throw a black cloud over current smokers who are trying to quit. Because even if people who smoked in the past are at greater risk than never smokers for developing lung cancer, quitting makes a difference. What do the statistics say about quitting or cutting down upon subsequent lung cancer risk?

How Often Do Smokers and Former Smokers Develop Lung Cancer?

 

If you smoked at some time in the past (or even if not because never smokers get lung cancer too...), take a minute to become familiar with the symptoms of lung cancer.

Reducing Your Risk of Lung Cancer

healthy diet can reduce lung cancer risk

superfoods for reducing the risk of lung cancer

exercise

What Else This Information Tells Us

Looking at studies of cancer risk after quitting smoking confirms what we already know: most people who develop lung cancer are non-smokers. This is important in many ways.

One, it tells us that encouraging smoking cessation isn't enough to eliminate lung cancer deaths.  Raising awareness about the risk of smoking is certainly important, but it can also be detrimental when it is the only effort being forth to make a difference with lung cancer.

Research into the causes of lung cancer has lagged behind what would be expected with other cancers, largely due to its being dismissed as being caused by smoking.  A quick calculation can drive home this point.  In 2016 it's expected that 40,000 people with die from breast cancer.  At the same time it's expected that 23,000 will die from radon induced lung cancer - a disease that is completely preventable if people would all check their homes for radon levels.  If we had a way to inexpensively test for, and eliminate the cause of over 50% of lung cancers, everyone would be very familiar with the process, yet not everyone is aware of simply testing their homes for radon.

A second major concern is former smokers.  We now have testing available for those who meet the criteria.  But people who quit 10 years ago or 30 years ago need to know that they are still at risk >  (And since lung cancer in never smokers is increasing, everyone should be aware...)

A final concern is the stigma.  We need to stop asking people with lung cancer if they smoked and leave the assessment of possible causes to epidemiologists.  It's time for us to love and care for people with lung cancer in the same we do people with other types of cancer.

Source:

Mong, C., Garon, E., Fuller, C. et al. High Prevalence of Lung Cancer in a Surgical Cohort of Lung Cancer Patients a Decade After Smoking Cessation. Journal of Cardiothoracic Surgery. 2011. 6(1):10.

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