What is Cancer?

Cancer refers to diseases in which abnormal cells divide out of control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems, which help the body get rid of toxins.

There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start—for example, lung cancer begins in the lung and laryngeal cancer begins in the larynx (voice box).

Symptoms can include:

• A thickening or lump in any part of the body
• Weight loss or gain with no known reason
• A sore that does not heal
• Hoarseness or a cough that does not go away
• A hard time swallowing
• Discomfort after eating
• Changes in bowel or bladder habits
• Unusual bleeding or discharge
• Feeling weak or very tired

How Is Smoking Related to Cancer?

Smoking can cause cancer and then block your body from fighting it:

• Poisons in cigarette smoke can weaken the body’s immune system, making it harder to kill cancer cells. When this happens, cancer cells keep growing without being stopped.
• Poisons in tobacco smoke can damage or change a cell’s DNA. DNA is the cell’s “instruction manual” that controls a cell’s normal growth and function. When DNA is damaged, a cell can begin growing out of control and create a cancer tumor.

Doctors have known for years that smoking causes most lung cancers. It’s still true today, when nearly 9 out of 10 lung cancers are caused by smoking cigarettes. In fact, smokers have a greater risk for lung cancer today than they did in 1964, even though they smoke fewer cigarettes. One reason may be changes in how cigarettes are made and what chemicals they contain.

Treatments are getting better for lung cancer, but it still kills more men and women than any other type of cancer. In the United States, more than 7,300 nonsmokers die each year from lung cancer caused by secondhand smoke. Secondhand smoke is the combination of smoke from the burning end of a cigarette and the smoke breathed out by smokers.

Smoking can cause cancer almost anywhere in your body, including the:

• Blood (acute myeloid leukemia)
• Bladder
• Cervix
• Colon and rectum
• Esophagus
• Kidney and renal pelvis
• Larynx
• Liver
• Lungs
• Mouth and throat
• Pancreas
• Stomach
• Trachea, lung. and bronchus

Men with prostate cancer who smoke may be more likely to die from these diseases than nonsmokers.

Smokeless tobacco, such as chewing tobacco, also causes cancer, including cancers of the:

• Esophagus
• Mouth and throat
• Pancreas

How Can Smoking-Related Cancers Be Prevented?

• Quitting smoking lowers the risks for cancers of the lung, mouth, throat, esophagus, and larynx.
  • Within 5 years of quitting, your chance of getting cancer of the mouth, throat, esophagus, and bladder is cut in half.
  • Ten years after you quit smoking, your risk of dying from lung cancer drops by half.

  If nobody smoked, one of every three cancer deaths in the United States would not happen.

Cancer Screening

Screening for Cervical and Colorectal Cancers

Research shows that screening for cervical and colorectal cancers, as recommended, helps prevent these diseases. Screening for cervical and colorectal cancers helps find these diseases at an early, and often highly treatable, stage. CDC offers free or low-cost cervical cancer screening nationwide.

Health care reform through the Affordable Care Act increases access to cervical and colorectal cancer screening through expanded insurance coverage and eliminating cost-sharing. In addition, CDC’s Screen for Life: National Colorectal Cancer Action Campaign informs people aged 50 years and older about the importance of having regular colorectal cancer screening tests.

Screening for Lung Cancer

People who have smoked for many years may consider screening for lung cancer a type of scan called low-dose computed tomography (LDCT). Talk to your doctor about lung cancer screening and the possible benefits and risks. Lung cancer screening is not a substitute for quitting smoking.

The U.S. Preventive Services Task Force recommends yearly screening for lung cancer with low-dose computed tomography for adults who are:

• 50 to 80 years of age and
• have a 20 pack-year smoking history (meaning they have smoked at least one pack of cigarettes per day for at least 20 years) and
• currently smoke, or have quit within the past 15 years

The Task Force recommends that screening stop once a person has not smoked for 15 years or if they develop a health problem that makes them unable or unwilling to have surgery if lung cancer is found.

How Is Cancer Treated?

The treatment for cancer depends on the type of cancer and the stage of the disease (how severe the cancer is and whether it has spread). Doctors may also consider the patient’s age and general health. Often, the goal of treatment is to cure the cancer. In other cases, the goal is to control the disease or to reduce symptoms for as long as possible. The treatment plan for a person may change over time.

Most treatment plans include surgery, radiation therapy, or chemotherapy. Other plans involve biological therapy (a treatment that helps your immune system fight cancer).

Some cancers respond best to a single type of treatment. Other cancers may respond best to a combination of treatments.

For patients who get very high doses of chemotherapy or radiation therapy, a stem cell transplant, also known as a bone marrow transplant, may be recommended by their doctor. This is because high-dose therapies destroy both cancer cells and normal blood cells.

Quitting smoking improves the outlook (the prognosis) for people with cancer. People who continue to smoke after diagnosis raise their risk for future cancers and death. They are more likely to die from cancer than nonsmokers and are more likely to develop a second (new) tobacco-related cancer.

Colorectal Cancer and Ostomies

An ostomy (or stoma) is a surgical opening made to the body that allows waste to be eliminated from the body. Ostomies are used in treatment or management of cancer or other diseases. Ostomies are needed when the body’s normal opening is closed or altered as part of cancer treatment. An ostomy pouch is located around the opening to collect waste for removal. Ostomies are usually done during the first stages of surgical treatment to remove cancer. For colorectal cancer patients, a colostomy (surgical openings from the bowel or colon to the abdomen) can be a lifesaving surgery. An ostomy can be temporary or permanent. Temporary ostomies are used while the affected area of the body heals. Permanent ostomies are used when cancer has resulted in the removal of the entire colon or the end of it.

Tobacco use is a leading cause of cancer and of death from cancer. People who use tobacco products or who are regularly around environmental tobacco smoke (also called secondhand smoke) have an increased risk of cancer because tobacco products and secondhand smoke have many chemicals that damage DNA.

Tobacco use causes many types of cancer, including cancer of the lung, larynx (voice box), mouth, esophagus, throat, bladder, kidney, liver, stomach, pancreas, colon and rectum, and cervix, as well as acute myeloid leukemia. People who use smokeless tobacco (snuff or chewing tobacco) have increased risks of cancers of the mouth, esophagus, and pancreas.

There is no safe level of tobacco use. People who use any type of tobacco product are strongly urged to quit. People who quit smoking, regardless of their age, have substantial gains in life expectancy compared with those who continue to smoke. Also, quitting smoking at the time of a cancer diagnosis reduces the risk of death.

Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.

To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.

Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer.

Smoking is the leading cause of cancer in the United States.

Smoking increases the risk of many types of cancer. These include:

• Lung cancer.
• Throat cancer.
• Mouth cancer.
• Nasal cavity cancer.
• Esophageal cancer.
• Stomach cancer.
• Pancreatic cancer.
• Kidney cancer.
• Bladder cancer.
• Cervical cancer.
• Acute myeloid leukemia.

A smoker’s risk of cancer can be 2 to 10 times higher than it is for a person who never smoked. This depends on how much and how long the person smoked.

Lung cancer is the leading cause of cancer death in both men and women. In 2014, about 19% of adult men and about 15% of adult women were smokers. In the last 30 years, the total number of smokers has decreased, especially among men. Since the 1980s, deaths caused by lung cancer in men have been decreasing.

From 2011 to 2014, smoking decreased among middle school and high school students. Cigarette smoking among male and female high school students of all ethnic groups increased markedly during the early 1990s, with rates between 20% and 30%. By 2019, smoking in this population had declined to 6%. Raising the legal age to buy and use tobacco products is being studied as a way to prevent or decrease smoking and other tobacco use among young people.

Smoking causes many other health problems.

Smoking is linked with many diseases besides cancer. These include:

• Heart disease.
• Stroke.
• Emphysema.
• Bronchitis.

Other health problems that may be linked to smoking are:

• Cataracts.
• Bone disease.
• Trouble becoming pregnant.

Smoking during pregnancy may cause problems such as slow growth of the fetus and low birth weight.

Being exposed to secondhand smoke increases the risk of cancer and other diseases.

Smoking can also affect the health of nonsmokers. Smoke that comes from the burning of a tobacco product or smoke that is exhaled by smokers is called secondhand smoke. Inhaling secondhand smoke is called involuntary or passive smoking.

The same cancer-causing chemicals inhaled by tobacco smokers are inhaled in lower amounts by people exposed to secondhand tobacco smoke. Nonsmokers who are exposed to secondhand smoke have a higher risk of lung cancer and coronary heart disease. Children exposed to tobacco smoke have higher risks of the following:

• Sudden infant death syndrome (SIDS).
• Worsened asthma.
• Ear infections.
• Respiratory problems such as lung infections, coughing, wheezing, or trouble breathing.

Quitting smoking improves health in smokers of all ages.

The risk of most health problems from smoking, including cancer and heart and lung disease, can be lowered by stopping smoking. People of all ages can improve their health if they quit smoking. Quitting at a younger age will improve a person's health even more. People who quit smoking cut their risk of lung cancer by 30% to 50% after 10 years compared to people who keep smoking, and they cut their risk of cancer of the mouth or esophagus in half within 5 years after quitting.

The damage caused by smoking is even worse for people who have had cancer. They have an increased risk of cancer recurrence, new cancers, and long-term side effects from cancer treatment. Quitting smoking and stopping other unhealthy behaviors can improve long-term health and quality of life.

Different ways to quit smoking have been studied. The following are the most common methods used to help smokers quit:

Counseling

People who have even a short counseling session with a health care professional are more likely to quit smoking. Your doctor or other health care professional may take the following steps to help you quit:

• Ask about your smoking habits at every visit.
• Advise you to stop smoking.
• Ask you how willing you are to quit.
• Help you plan to quit smoking by:
  • setting a date to quit smoking;
  • giving you self-help materials;
  • recommending drug treatment.
• Plan follow-up visits with you.

The Lung Health Study found that heavy smokers who received counseling from a doctor, took part in group sessions with other smokers to change their behavior, and used nicotine gum were more likely to quit smoking compared with smokers who did not receive counseling from a doctor, take part in group sessions, and use nicotine gum. They also had a lower risk of lung cancer, other cancers, heart disease, and respiratory disease.

Childhood cancer survivors who smoke may be more likely to quit when they take part in programs that use peer-counseling. In these programs, childhood cancer survivors are trained in ways to give support to other childhood cancer survivors who smoke and want to quit. More people quit smoking with peer-counseling than with self-help programs. If you are a childhood cancer survivor and you smoke, talk to your doctor about peer-counseling programs.

Drug treatment

Treatment with drugs is also used to help people quit smoking. These include nicotine replacement products and non-nicotine medicines. People who use any type of drug treatment are more likely to quit smoking after 6 months than those who use a placebo or no drug treatment at all.

Nicotine replacement products have nicotine in them. You slowly reduce the use of the nicotine product in order to reduce the amount of nicotine you take in. Using a nicotine replacement product can help break the addiction to nicotine. It lessens the side effects of nicotine withdrawal, such as feeling depressed or nervous, having trouble thinking clearly, or having trouble sleeping. Nicotine replacement products, used alone or in combination, have been shown to help people quit smoking. These include:

• Nicotine gum.
• Nicotine patches.
• Nicotine nasal spray.
• Nicotine inhalers.
• Nicotine lozenges.

Nicotine replacement products can cause problems in some people, especially:

• Women who are pregnant or breast-feeding.
• Teenagers.
• People with any of the following medical problems:
  • Heart rhythm problems.
  • High blood pressure that is not controlled.
  • Esophagitis.
  • Ulcers.
  • Insulin-dependent diabetes.
  • Asthma.

Other medicines that do not have nicotine in them are used to help people quit smoking. These include:

• Bupropion (also called Zyban).
• Varenicline (also called Chantix).

These medicines lessen nicotine craving and nicotine withdrawal symptoms.

It is important to know that bupropion and varenicline may cause serious psychiatric problems. Symptoms include:

• Changes in behavior.
• Aggressive behavior.
• Anxiety.
• Nervousness.
• Depression.
• Suicidal thoughts and attempted suicide.

Varenicline may also cause serious heart problems.

Before starting to take bupropion or varenicline, talk to your doctor about the important health benefits of quitting smoking and the small but serious risk of problems with the use of these drugs.

Smoking reduction

When smokers do not quit smoking completely but smoke fewer cigarettes (smoking reduction) they may still benefit. The more you smoke, the higher your risk of lung cancer and other cancers related to smoking. Studies show that smokers who cut back are more likely to stop smoking in the future.

Smoking less is not as helpful as quitting smoking altogether, and is harmful if you inhale more deeply or smoke more of each cigarette to try to control nicotine cravings. In smokers who do not plan to quit smoking completely, nicotine replacement products have been shown to help them cut down the number of cigarettes they smoke, but this effect does not appear to last over time.

The following resources can help you quit smoking:

• Consumer information about quitting smoking is available at the www.smokefree.gov website.
• The online QuitGuide may help you 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.

There are new and different types of tobacco and nicotine products.

The use of new or different types of tobacco products and devices that deliver nicotine is increasing rapidly in the United States, especially the use of electronic-cigarettes (e-cigarettes) by adults and adolescents.

Examples of new and different tobacco and nicotine products and devices include the following:

• E-cigarettes.
• Small cigars.
• Water pipes (hookahs) for smoking tobacco.
• Flavored smokeless tobacco products.

More studies are needed to understand the risks and benefits of using these products.