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 tumour.

Doctors have known for years that smoking causes most lung cancers. It’s still true today, when nearly 9 out of 10 lung cancers deaths are caused by smoking cigarettes or secondhand smoke exposure. 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, but lung cancer still kills more men and women than any other type of cancer. 

Second-hand smoke is the combination of smoke from the burning end of a cigarette and the smoke breathed out by someone smoking. 

Smoking can cause cancer almost anywhere in your body: 

• Bladder 

• Blood (acute myeloid leukaemia) 

• Cervix 

• Colon and rectum (colorectal) 

• Oesophagus 

• Kidney and ureter 

• Larynx 

• Liver 

• Oropharynx (includes parts of the throat, tongue, soft palate, and the tonsils) 

• Pancreas 

• Stomach 

• Trachea, bronchus, and lung

Men with prostate cancer who smoke may be more likely to die from prostate cancer 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?

The most important thing you can do to prevent smoking-related cancer is not to smoke cigarettes, or to quit if you do. It is also important to avoid secondhand smoke.

Quitting smoking lowers the risk for 12 types of cancer: cancers of the lung, larynx, oral cavity and pharynx, esophagus, pancreas, bladder, stomach, colon and rectum, liver, cervix, kidney, and acute myeloid leukemia (AML). 

Within 5-10 years of quitting, your chance of getting cancer of the mouth, throat, or voice box drops by half. 

Within 10 years of quitting, your chance of getting cancer of the bladder, esophagus, or kidney decreases. 

Within 10-15 years after you quit smoking, your risk of lung cancer drops by half. 

Within 20 years after you quit smoking, your risk of getting cancer of the mouth, throat, voice box, or pancreas drops to close of that of someone who does not smoke. Also, the risk of cervical cancer drops by about half.