Cancer, Latin for "crab. A large growth inside the body. A skin cancer is a tumour (collection of cells) of the skin which is malignant. The common types of skin carcinoma (cancers) are 1 :
- Basal cell carcinoma
- Sqaumous cell carcinoma
Causes of the disease
The argument for the causes of cancer are long and many. Some basic causes can be list as :
- Genetics - some people are believed to be at a higher risk for cancers because of who they are. Usually, if the parents have a high chance of getting a cancer, so do the children. These people need to be very aware of any changes in their bodies 2.
- Radiation - sunlight is a form of radiation !! Long term exposure to sunlight can cause cell changes on the skin which may eventually develop into a cancer. The rays especially responsible for this would be ultra-violet radiation 3. However, exposure to x-rays, mining minerals (e.g. radium) and nuclear fission (e.g. the accident that occurred in chernobyl, u.s.s.r) may also lead to the formation of a cancer. Radiation to the body accumilates, but occasionally a dose may have an adverse impact on a persons skin cells.
- Constant exposure to physical stimuli - e.g. heat
- Constant exposure to chemical stimuli - e.g. benzine.
- Some viruses - E.g. human papillomavirus, Epstein Barr virus and hepatitis B virus. Infection with these viruses may leave a person susceptible to cancer due to changes that they may produce in the body's cells.
The higher layers of the atmosphere has a layer of gas which consists of three oxygen atoms. This gas is called ozone, and its presence is responsible for greatly reducing the amount of harmful ultra-violet rays emitted from the sun. In some areas of the world, the ozone layer is very thin, or completely depleted. Unfortunately, New Zealand and Australia belong in areas where this has occurred. Thus the incidence of skin cancers due to radiation present in sunlight is very high. The incidence of melanoma (a particularly nasty form of skin cancer has been linked to the position of the country)4.
Occupational exposure to continuous doses of arsenic to the skin was found to produce a high incidence of skin cancer. Arsenic was typically found in alloy metal, electrical conductors, and some medications. 2
The first symptoms of a carcinoma is a change in the appearance of the skin. There is often no pain associated with skin cancer, which is the reason why it can go undetected for many months. Basal and sqaumous cancers can cause recurrent ulcers (wounds that keep coming back), which never completely heal. The size of the tumour can slowly (or rapidly) increase. There may also be a lumpiness in the area (elevation) which means that the tumour is starting to invade the tissue underneath the skin.
Skin cancer is a fairly common form of cancer. Especially common in regions in the world where there is a lot of sunlight, and the population is fair skinned. In general, the frequency of cancer increases with age. This may be due to the fact that the persons immune system function is decreased as time goes by. The estimated cancer incidence by site and sex in 1996 was 3% for both males and females. The estimated deaths by cancer 2% for males and 1% for females.2
Characteristics of skin cancers