I received a bizarre text last week. A respondent, wanted to know how to diagnose breast cancer. She has a lump in her left breast, but she left further descriptions of the lump and wrote “Doc what causes cancer? “ I was a little bit disconcerted. Which should I answer first?
I know I have written about cancer and its causes ad nauseam. Since the questions will continue to come, I shall continue to answer. Now let us begin.
Causes of cancer include:-
• Cells with genetic defects appear in the body every day : so many millions of cells are being made, that some mistakes are inevitable.
• But most cells die almost immediately, because they are too faulty to survive, or because they are recognized as abnormal and eaten by white blood corpuscles. Others are only slightly defective, and not malignant.
• Only very rarely do malignant cells survive and reproduce successfully.
• Appearance of cancer in a person may simply be due to this unlucky change.
• Alternately, it may be that the body has “immunity “ to such malignant cells, and that, this sometimes breaks down. This would explain, why cancer can remain “dormant” in a person for many years, and suddenly erupt.
A few factors have been recognized that do make the genetic damage in cells more likely. But they can only explain a tiny proportion of the cancer that occurs.
1. Certain chemicals – can cause cancer to form, if they are repeatedly in contact with the body over a period of time. Such chemicals are called carcinogens, and include some hydrocarbons. Apart from tobacco smoke, these carcinogens usually affect workers whose job brings them into regular contact with them. However atmospheric pollution may also be slightly carcinogenic.
2. Certain viruses – can pass malignant tumors from one animal to another, and the same may occur in man. But so far only one rare form of cancer is thought to be caused this way. Apart from this, human cancer seems not to be virus Induced and therefore not infectious.
3. Ionizing radiation – without correct protection, x-rays can cause skin cancer, and radiation can cause leukemia. Also ultraviolet rays as in sunlight, may cause skin cancer in some circumstances.
4. Continued physical irritation – there is disagreement over this, but some experts believe that continued physical disturbance of the skin or mucous membrane can cause cancer. If so, the sharp edges of a broken tooth, for example, could eventually cause cancer of the mouth. Others argue that such irritation can only accelerate an existing cancerous growth.
5. Correlative factors.
Some individuals are more likely to develop cancer than others.
a. Heredity. Actual cancerous growth are not inherited. But a pre-disposition for cancer can be passed on. It may be that some inherited characteristics make a person’s cell more likely to become malignant.
b. Age. Most cancers occur in the 50 to 60 age group. However, children and adolescents
are susceptible to leukemia, brain tumors and sarcoma of the bone.
c. Sex. In almost all countries cancer occurs more frequently in men than in women.