(A) Cancer Genetics

One of the most important breakthroughs in cancer research came in the late 1970s when scientists discovered that all types of cancer begin with the genetic material within normal body cells becoming damaged. Every cell contains genetic information in the form of more than a hundred thousand pairs of genes which work together to regulate the activities of the cell. A cell can become cancerous when specific genes, such as those that control division, become damaged beyond repair. How and why genes become damaged is still a hot topic for research.  However, it would seem that faulty genes are either inherited or they are caused by carcinogens (cancer-causing agents), for example sunlight ( ultraviolet radiation) and cigarette smoke.

Our body cells are continually exposed to carcinogens. However in the majority of cases cancer does not occur. There are many reasons why this is so, such as:

Healthy cells can  repair their own faulty genes so that they continue to function properly.  More than one gene has to be damaged in order for cancer to develop. The body's immune system can normally destroy any cancer cells before they get the chance to multiply and form a tumour.

(B) Causes of Cancer

Although most cancers appear to be caused by several factors, including genetic or inherited ones, a main environmental cause can often be identified for a particular cancer i.e. smoking cigarettes is commonly associated with lung cancer.

About 35% of stomach cancer and prostate cancer cases are related to diets of unhealthy foods with little or no fresh fruit and vegetables. 30% of lung, breast, colon, and throat cancers are related to tobacco products such as cigarettes and cigars. 10% of skin cancer cases are related to the sun and UV rays. 7% of lymphoma, leukaemia, bone cancer and liver cancer cases are related to viruses such as Epstein Barr, HIV, Hepatitis C etc. Pesticides and chemicals, or occupational factors contribute about 4% or mouth, throat, stomach and lymphoma cancer cases. About 3% of stomach, colon and liver cancer have been linked to excessive consumption of alcohol.

(C) Cancer biology and ageing

The behaviour of some cancer changes with the age of the patient as a result of two mechanisms.

1. Older persons develop tumours that are different from younger persons.

2. The older person modulates tumour growth differently.

Two observations have clinical relevance:

1.Contrary to common expectations, cancer may become more aggressive with age.

2. Age itself should not determine the treatment of cancer. The aggressiveness of the tumour is better judged from the tumour characteristics than from the age of the patient.

Cancer is more common among older people. Their body cells have had more time to accumulate genetic damage. The body's defenses against cancer, particularly the cells and proteins of the immune system, also gradually become less efficient with age. In addition a cancer that began earlier in life may not be diagnosed until old age because some cancers take years to develop because of the latency or dormant effects.

Life expectancy has increased dramatically over the last 50 years. This means that cancer is now one of the most common causes of death in the developed world, second only to coronary heart disease.

(D) Modern advances in cancer treatment 

New therapies for the treatment of cancer that are currently being assessed include inactivating the damaged genes so that they no longer send messages to the cell, and boosting the body's natural immune system so that it has the ability to destroy any cancerous cells. These therapies are still in the experimental phase. However, the American Cancer Society, the National Cancer Institute of the UK, in collaborations with many other Cancer Research Centres in the world, are working towards making them viable treatment options for future generation.
 

Finally, we must not forget that the introduction of modern technological medicine into palliative care have benefited many patients with advanced cancer.