Does Nicotine Cause Cancer?

Medically reviewed by Suzanne Falck, MD, FACP on April 6, 2017Written by Elizabeth Connor on April 6, 2017

Overview of nicotine

Many people link nicotine to cancer, especially lung cancer. Nicotine is one of many chemicals in raw tobacco leaves. It survives the manufacturing processes that produce cigarettes, cigars, and snuff. It is the addictive element in all forms of tobacco.

Researchers are looking at how nicotine contributes to the development of cancer. While it may be too early to say nicotine causes cancer, questions are being raised about how the chemical acts in non-tobacco forms like e-cigarettes and nicotine-replacement patches. Researchers are discovering that the connection between nicotine and cancer is more complicated than commonly thought.

Does nicotine cause cancer?

Nicotine exerts its effects through a chemical pathway that releases dopamine to the body’s nervous system. Repeated exposure to nicotine sets up a dependence and withdrawal response. This response is familiar to anyone who has attempted to quit using tobacco products. More and more, scientists are demonstrating nicotine’s powers beyond its addictiveness. Recent studies suggest that nicotine has several cancer-causing effects:

  • In small doses, nicotine speeds up cell growth. In larger doses, it’s poisonous to cells.
  • Nicotine kick-starts a process called epithelial-mesenchymal transition (EMT). EMT is one of the important steps in the path toward malignant cell growth.
  • Nicotine decreases the tumor suppressor CHK2. This may allow nicotine to overcome one of the body’s natural defenses against cancer.
  • Nicotine can abnormally speed up the growth of new cells. This has been shown in tumor cells in the breast, colon, and lung.
  • Nicotine can lower the effectiveness of cancer treatment.

How does tobacco cause lung cancer?

Scientists saw a link between cancer, especially lung cancer, and tobacco long before they figured out exactly how the relationship worked. Today, it’s known that tobacco smoke contains at least 70 cancer-causing chemicals. The long-term exposure to these chemicals is thought to generate the cell mutations that lead to cancer.

Tar is the residue that’s left behind in your lungs from the incomplete burning of the chemicals in a cigarette. Chemicals in the tar inflict biological and physical damage on the lungs. This damage may encourage tumors and make it difficult for the lungs to expand and contract properly.

How to quit smoking

If any of the following habits apply to you, you may be addicted to nicotine:

  • you smoke in the first five minutes after waking
  • you smoke despite illness, such as respiratory tract infections
  • you wake during the night to smoke
  • you smoke to reduce withdrawal symptoms
  • you smoke more than a pack of cigarettes a day

When you decide to quit smoking, the first part of your body involved is your head. The American Cancer Society’s path to quitting tobacco begins with how to mentally prepare for the task.

1. Decide to quit smoking

Resolving to quit smoking is a deliberate and powerful act. Write down the reasons you want to quit. Fill in details. For example, describe the health benefits or cost savings you’re expecting. The justifications will help if your resolve begins to weaken.

2. Decide on a day to quit

Pick a day within the next month to begin life as a nonsmoker. Quitting smoking is a big deal, and you should treat it that way. Give yourself time to prepare, but don’t plan it so far in advance that you’re tempted to change your mind. Tell a friend about your quit day.

3. Have a plan

You have several quitting strategies to choose from. Consider nicotine replacement therapy (NRT), prescription drugs, quitting cold turkey, or hypnosis or other alternative therapies.

Popular prescription smoking cessation drugs include bupropion and varenicline (Chantix). Talk with your doctor to develop the best treatment plan for you.

4. Get help

Take advantage of counseling, support groups, telephone quit lines, and self-help literature. Here are some websites that may help you in your effort to quit smoking:

Coping with nicotine withdrawal »

Health benefits of quitting smoking

The United Kingdom’s National Health Service summarizes the health benefits that begin the very day you decide to quit smoking and continue for years to come:

  • After 20 minutes: Your pulse rate returns to normal.
  • After 8 hours: Nicotine and carbon monoxide levels in your blood reduce by more than half. Oxygen levels return to normal.
  • After 48 hours: Carbon monoxide and nicotine are eliminated from your body. Mucus and other smoking debris begin to clear from your lungs. Your senses of taste and smell improve.
  • After 72 hours: You breathe easier. Breathing tubes relax and your energy increases.
  • After 2 to 12 weeks: Your circulation improves.
  • After 3 to 9 months: Lung function increases as much as 10 percent.
  • After 1 year: Your risk of heart disease is about half that of a smoker.
  • After 10 years: Your risk of lung cancer is half that of a smoker.
  • After 15 years: Your risk of heart attack is about the same as someone who has never smoked.

What happens when you quit smoking? »

Bottom line

Research continues on the health impacts of nicotine use and effective ways to quit.

While scientists continue to study the effects nicotine has on cancer, the cancer-causing elements of tobacco are well-known. Your best bet is to quit all tobacco products to lower your chances of developing cancer. If you already have cancer, quitting smoking may help your treatment be more effective.

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