Study Finds Lung Cancer Risk Drops 39% After Five Years of Quitting Smoking

Smoking is the leading cause of death in most parts of the world. According to, tobacco causes nearly half the deaths from 12 kinds of cancers combined. Researchers analyzed around 346,000 patients who died from the cancer of the lung, liver, mouth, larynx, colon, stomach, pancreas, kidney, bladder, cervix and acute myeloid leukemia.

Considering the correlation between smoking and lung cancer, cigarettes cause 80.2% of lung cancer related deaths.

Risk of Lung Cancer after Quitting Smoking

The Journal of the National Cancer Institute released a study on the relative risk of cancer after quitting smoking. Researchers found that five years after quitting smoking, ex-smokers experienced a 39% decrease in the risk of developing lung cancer.

The study, carried out by Vanderbilt University Medical Center, took data from the Framingham Heart Study. Framingham’s study is an important, innovative and unique study that receives praise because it continued to ask the participants about their smoking habits every 2 to 4 years.

The continued follow-up was able to provide data from 8,907 participants that were followed for 25 – 34 years. This data correlated with decreases and increases in the participants’ smoking habits. For instance, data showed how much or how little a smoker smoked in different phases of their lives. Then, the researchers at Vanderbilt University examined this information.

What Researchers Found

Who Is More Likely to Be Diagnosed with Lung Cancer

Out of the 8,907 participants that were followed for 25 – 34 years, there were 284 people who were diagnosed with lung cancer over the data’s 34-year period.

There are 3 types of smokers when it comes to the number of cigarettes being consumed. Light smokers consume between 1-10 cigarettes daily. Moderate smokers smoke 11-19 cigarettes a day. And heavy smokers smoke 20 or more cigarettes per day. Out of these three levels, heavy smokers were of the most concern, with 93% of those with lung cancer having smoked a pack of cigarettes or more for a period of at least 21 years.

When the Risk of Cancer Falls

Researchers also found a strong correlation between quitting smoking and a reduction in chances of developing lung cancer. Heavy smokers that stopped smoking had a 39% decreased risk of contracting lung cancer when compared to participants that continued their heavy smoking habits. That risk dropped to that level after quitting for five years.

The authors of the study claim that it’s a good time for smokers to quit because cancer risks drop quickly after ceasing smoking.

This means that it’s never too late to stop smoking. Many people believe that quitting smoking is not worth the struggle and that the damage to their body is already done so stopping the habit will not have any transformative effect on their life. As we can see from the Framingham Heart Study, even heavy smokers can benefit dramatically from stopping smoking. Even those who have smoked for a long time and have tried almost every stop smoking product like nicotine gums, nicotine inhalers, nicotine patches, vaping or even Chantix and Zyban.

How to Stop Smoking

There are many ways to stop smoking. Some include stop smoking products that contain nicotine, such as nicotine gums and patches and vaping. These aids help smokers experience fewer cravings and reduce their nicotine intake before stopping completely. Other products are pills of varenicline like Chantix and Zyban do not contain nicotine. Some other common stop smoking methods are natural such as going cold turkey, using hypnosis or taking natural herbs like St. John’s wort or lobelia. And other ways that have gained prominence in the latest years are using psychological and behavioral methods to stop smoking, an example of which is Smoking Cessation Formula.

The important thing is that whichever way you may choose to quit smoking, the data still shows that the risk of lung cancer will continue to decline year after year.

If yourself, a family member, a loved one, a friend or a colleague are smoking and want to increase your health and decrease the chances of getting a life-threatening disease, then search about how you can overcome this addiction. Ask your doctor for help or take advantage of the many products, advice and help you can find on the internet.

Does the Risk of Lung Cancer Disappear?

Researchers discovered and warned that 40% of cancers in the group that was considered heavy smokers didn’t present until 15 years after they quit.

Ex-smokers still have a much higher risk of lung cancer than those that have never smoked a cigarette in their life. Researchers claim that ex-smokers have a threefold higher risk of getting lung cancer over those that have never smoked. Even ex-smokers that hadn’t smoked for a period of 25 years still had a higher risk of lung cancer than those who never smoked.

The risks of cancer from smoking cannot be overstated, claim researchers. Former heavy smokers will retain their elevated risk of cancer for decades after they smoke their last cigarette. That’s why specialists emphasize that it’s important to have a lung screening performed routinely to ensure that cancer is not found even if a smoker has not smoked in decades. In addition, a screening will be able to detect the initial stages of a forming cancer, therefore, increasing the chances of curing it with the right treatment.

Researchers also found that the screening window lasts well past the current guideline even for smokers that quit 15 years ago or longer.


Quitting smoking decreases the risk of getting lung cancer. However, ex-smokers are in danger of developing the disease even 15 years after smoking their last cigarette. It’s advised to stop smoking as soon as possible using stop smoking aids or help and to visit your doctor regularly for a screening.</span

Melissa Thompson
Melissa Thompson writes about a wide range of topics, revealing interesting things we didn't know before. She is a freelance USA Today producer, and a Technorati contributor.