Smoking Cessation and Continued Risk in Cancer Patients (PDQ®)

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, a core part of our mission is to educate patients and the community about cancer. The following summary is trusted information from the NCI.


This patient summary on smoking cessation and continued risk in cancer patients is adapted from a summary written for health professionals by cancer experts. This and other credible information about cancer treatment, screening, prevention, supportive care, and ongoing clinical trials is available from the National Cancer Institute. This brief summary describes smoking and the risks of continued smoking in adult cancer patients.


This summary briefly covers smoking as a primary risk factor for cancer, but the main focus is on the effect of smoking on cancer recurrence and diagnosis of a second primary cancer; patterns of quitting and continued smoking in cancer patients; and recommendations for cancer patients to quit smoking. Information on cancer prevention and quitting smoking in healthy people is readily available elsewhere. The information presented in this summary is related to smoking, rather than using other forms of tobacco, such as snuff or chewing tobacco.

Smoking as a Primary Risk Factor

It has been known for almost 50 years that tobacco use can be linked to cancers of the lung and head and neck. Eighty-five percent of the cases of head and neck cancer found each year are associated with tobacco use. Long-term smoking that begins before age 30 also increases the risk for developing colorectal cancer. Smoking contributes to cancer development by causing mutations in genes, impairing lung function, and decreasing the effectiveness of the immune system. See the following for more information:

Poorer Treatment Response in Cancer Patients

If cancer is diagnosed in a smoker, studies have found that quitting smoking will still be helpful. Even recent quitters are more likely to recover from cancer than smoking patients are. Continuing to smoke may decrease the effectiveness of treatment and may worsen treatment side effects. For example, patients who have received radiation therapy for laryngeal cancer are less likely to regain satisfactory voice quality if they continue to smoke. Also, wound healing following surgery will be more difficult if one continues to smoke.

Smoking as a Secondary Risk Factor

Whether a patient has a cancer that is smoking-related or nonsmoking related, he or she is at increased risk of developing a second cancer at the same or another site, if smoking is not stopped. The risk of developing a second cancer may persist for up to 20 years, even if the original cancer has been successfully treated.

Patients with oral and pharyngeal cancers who smoke also have a high rate of second primary cancers. The risk decreases significantly, however, after 5 years of not smoking.

Effects of a Cancer Diagnosis on Quitting Smoking and Remaining Abstinent

Most people who have a smoking-related cancer stop smoking or make serious efforts to quit when cancer is diagnosed. Patients who do not immediately stop smoking may be motivated to quit in the future. Some studies have shown that patients who have less intensive treatment are more likely to continue smoking, and if they quit, are more likely to start smoking again.

Smoking Intervention in Cancer Patients

Although smoking cessation research has been conducted in other patient groups, especially heart patients, few studies have involved cancer patients. These studies have shown the importance of involvement of physicians and other health care professionals in helping patients to stop smoking. The ASK, ADVISE, ASSIST, and ARRANGE model was developed in the late 1980s for health care providers and their patients who smoke. Using this model, the physician asks the patient about smoking status at every visit, advises the patient to stop smoking, assists the patient by setting a date to quit smoking, provides self-help materials, recommends use of nicotine replacement therapy (for example, the nicotine patch), and arranges for follow-up visits.

A smoking cessation study of eligible patients with cancer found that most who enrolled had a long-term smoking habit, drank alcohol several times per week, and were likely to be depressed. The study found that a smoking cessation program for such patients can be provided despite challenges, with special attention given to smokers with depression.

Not all smokers are motivated to stop smoking. Physicians should help patients become motivated to quit smoking. It is common for first time quitters to start smoking again once or many times. Quitters should be taught to anticipate stressful situations in which they will want to smoke, and to develop strategies for handling them. It may take more than a year for even motivated smokers to stop smoking. The following resources are designed to help people quit smoking:

  • Consumer information about quitting smoking is available at the Web site.
  • The online Quit Guide may help patients understand reasons for smoking and the best ways to quit.
  • The booklet Clearing the Air: Quit Smoking Today can be ordered at 1-800-4-CANCER (1-800-422-6237) or printed here.


Different ways to stop smoking are effective for different patients. Some smokers can quit with the help of counseling, while others may need nicotine replacement therapy or non-nicotine medicines to help them quit. Since patients can improve their health in many ways by quitting smoking, medicines are often prescribed with careful monitoring to help them succeed.

Nicotine Replacement Therapies

Nicotine replacement therapy may help with the withdrawal symptoms that patients experience when trying to stop smoking. Nicotine products include:

A physician should be consulted before starting any form of treatment, and the following groups should take special precautions:

  • Patients who are pregnant or nursing should get advice from a health care professional before using nicotine replacement products.
  • Patients who continue to smoke, chew tobacco, or use snuff should not use nicotine replacement products.
  • Patients aged less than 18 years and those who have the following conditions should check with a physician before using nicotine replacement products:

Non-nicotine Medicines

Non-nicotine medicines that have been studied to help people quit smoking include:

  • Varenicline (also called Chantix), a drug approved by the Food and Drug Administration (FDA) for smoking cessation that acts the same way nicotine acts in the brain. This results in less craving and fewer nicotine withdrawal symptoms. In June 2011, the FDA warned that varenicline may increase the risk of cardiovascular (heart and blood vessel) adverse events in patients with cardiovascular disease.
  • Bupropion (also called Zyban), the only antidepressant approved by the FDA for smoking cessation.
  • Fluoxetine (also called Prozac), an antidepressant shown to be effective in smoking cessation.

The FDA has directed manufacturers of bupropion and varenicline to add a boxed warning about the risk of depression, suicide, and other psychiatric events in patients who take these drugs, including:

These events have been reported in patients with or without a history of psychiatric illness. It is not known whether nicotine withdrawal is a factor in these psychiatric events. Fluoxetine has a boxed warning about an increased risk of suicide in young adults aged less than 25 years. (See the Depression and Suicide section in the PDQ summary on Pediatric Supportive Care.)

All patients taking these drugs, especially those with a history of psychiatric illness, should be closely monitored during smoking cessation.

The FDA advises that the important health benefits of quitting smoking should be weighed against the small but serious risk of problems with the use of these drugs.

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