Causes of Cancers

Exactly what causes cancer has not yet been confirmed. Evidence suggests, however, that cancer could result from complex interactions of viruses, a person’s genetic make-up, one's immune status and exposure to other risk factors which may promote cancer.

	Exposure to the sun’s ultraviolet rays and x-rays
	Use of tobacco and/or alcohol
	Polluted air and water
	Dietary factors such as high fat diet, specific food preservatives
	Exposure to a variety of chemicals such as asbestos, benzenes, some ingredients of cigarette smoke, etc

	Do not smoke, use tobacco products or inhale second hand smoke
	Limit your exposure to known carcinogens such as asbestos
	Limit your exposure to the sun’s ultraviolet (UV) rays
	Reduce stress. Emotional stress may weaken the immune system that is relied on to fight off stray cancer cells

Some Facts About Cancers in HK

Treatment of cancer using drugs that have direct tumor-killing properties. It is most effective against cancers that divide rapidly and have a good blood supply.

Side effects:

Since normal cells that make up the mucus lining of the intestinal tract, the hair producing cells, and the bone marrow cells are also rapidly-dividing cells, they are affected by chemotherapy. The resulting common side effects are: nausea and vomiting, hair loss, and bone marrow depression.

Nausea and vomiting: Patients will recover from nausea between 4 and 24 hours after it starts; and severe nausea usually follows a pattern, with the bouts of vomiting coming farther and farther apart.

Hair loss: Hair loss is mainly a psychological problem; there is no pain and hair does grow back.

Bone marrow depression: It is a more subtle and more serious concern. Some chemotherapies can slow down, or depress bone marrow cell reproduction, making one more susceptible to infection. If the depression is too severe, one will be put in the hospital and given antibiotics until his immune system recovers.


Radiation

Radiation therapy works by destroying cells, either directly or by interfering with cell reproduction using high-energy X-rays, electron beams or radioactive isotopes. Theoretically, normal cells are able to repair the damages of radiation better than are malignant and other abnormal cells. Thus, normal cells are able to recover from exposure to radiation and maintain integrity better than malignant cells.

Radiation therapy is the principal treatment for various skin cancers; cancers of the mouth, nasal cavity, pharynx and larynx; brain tumors and many gynaecological and prostate cancers. Radiation therapy also plays a leading role in conjunction with surgery and many other cancers.

Side effects:

Radiation nausea: The degree of which patients experience nausea following treatment varies. Generally, nausea is likely to be worst from two to several hours after treatment.

Hair loss: Hair loss will only occur within the radiation field.

Fatigue/Malaise: Some degree of tiredness and lack of energy are often experienced. Reduction in activities during treatment and immediately afterwards will be advised.

Blood count: This results from radiation exposure of bone marrow, and to a lesser extent, direct damage to lymphocytes in the blood stream and lymph nodes.

Mucous membranes: Whenever mucous membranes (ie. mouth, pharynx, esophagus, trachea, bowel bladder, rectum ) are withthin a radiation field, mucositis will be experienced.

Accessory glands: The acute effects of radiation will be felt by accessory glands producing saliva and mucus. This leads to a degree of sickness, oral discomfort, dryness and change in taste, irritating cough, urinary or bowel symptoms.

Surgery

Cancer surgery attempts to remove localized tumors completely or reduce the size of large tumors so that follow-up treatments by radiation or chemotherapy will be more effective. In the surgery, the surgeon may remove the primary tumor, some normal tissue surronding the tumor (to make sure that she/he gets it all), the lymph nodes near the primary tumor (to detect and prevent the spread of individual cancer cells that may already lodged in these lymph nodes), and any organs in the body that may already be affected by the cancers.