Causes of Cancer and Prevention
Cancer is a term used for a group of diseases characterized by:
- An abnormal and purposeless multiplication of cells;
- Ability to infiltrate the adjacent tissues or even distant organs; and
- The eventual death of the patient, if the tumor has progressed beyond that stage when it can be removed successfully.
Cancer can become in any part or any tissue of the body and can involve any type of body cells.
Cancer is classified into two main categories. i.e 1. Solid tumors and 2. Leukaemias and lymphomas.
Causes of Cancer:
Like any other chronic disease cancer is caused due to multiple causes. Environmental factors are generally supposed to be responsible for majority of cancer cases. Following are the important causes for cancer:
Smoking or chewing of tobacco is the major environmental cause of cancer of mouth, tongue, larynx, lungs, pharynx, stomach, pancreas and kidney.
Excessive consumption of alcohol is associated with the cancer of oesophagus and stomach.
High fat diet is related to breast cancer, dietary fiber to intestinal cancer, beef to bowel cancer and consumption of smoked fish is related to stomach cancer.
Exposure to chemicals such as benzene, arsenic, cadmium, chromium, vinyl chloride, polycyclic hydrocarbons, asbestos and many others is related to cancers of lungs and skin. Among these persons smokers are at high risk.
Many viruses are held responsible for many cancers. For example, hepatitis B virus can produce cancer of the liver. Human papilloma virus (HPV) is supposed to be responsible for T cell leukaemia or lymphoma. Similarly Hodgkin’s disease, Burkitt’s lymphoma and nasopharyngeal carcinoma are also supposed to be of viral origin.
Many infections caused due to parasites can increase the risk of malignant diseases. In the Middle East, schistosomiasis is supposed to be an important cause of the cancer of urinary bladder.
Customs, habits and life styles:
These can also be associated with increased risk of cancer. There is a definite association between smoking and lung cancer. Similarly tobacco chewing, betel chewing or chewing of pan masala (Gutka) has association with the cancer of oral cavity.
Other environmental factors:
Sunlight is associated with cancer of skin. Radiation is associated with leukaemia and consumption of oestrogen is related with breast cancer.
In addition to the above mentioned factors genetic factors are also important for certain cancers for example retinoblastoma is familial. Similarly leukaemia is common in Mongol children.
Early diagnosis, proper treatment, after care and rehabilitation are helpful in controlling the disease. The control of cancer is possible in one third of the cases. The control of cancer can be done by primary prevention and by secondary prevention.
It is possible to control many of the causative factors of the cancer in the general population as well as in particular occupational groups by following measures:
- Control of tobacco and alcohol consumption.
- Improvement of personal hygiene.(to prevent cervix cancer).
- Reduction in the amount of radiation.
- Protect workers from industrial carcinogenic chemicals.
- Immunization against hepatitis B virus(to protect primary liver cancer).
- Testing of food,drugs and cosmetics for their carcinogenic activity.
- Control of air pollution.
- Early detection and treatment of precancerous lesions such as warts, chronic gastritis, chronic cervicitis etc.
- Help of law to control know carcinogens.
- Cancer education to motivate people for early diagnosis and early treatment.
For secondary prevention following measures are taken.
- Registration of cancer cases should be done to assess the severity of the problem and for providing the necessary services. Registration of cancer cases can be done in hospitals. The hospital based registries should be extended to population base registry.
- Early detection can be done by cancer screening at a premalignant stage. Effective screening programmes have developed for cervical cancer, breast cancer and for oral cancer.
- Treatment facilities should be receivable to all cancer patients.
The cancer treatment consists of the following:
- Radiotherapy; and
Multi modality approach (i.e combination of any two or all the three above mentioned therapies) to cancer control has become a standard practice in cancer centers all over the world. Those patients who have crossed the curable stage for them the goal must be to provide pain relief.