The mortality rate due to cancer in the world is estimated at 12%, 33% caused by infectious and parasitic diseases and 29% to circulatory problems. In industrial countries the level is at 21% for cancers and only 1% for infectious and parasitic diseases. Developing countries see their levels as respectively 9% and 43%, however these levels must be viewed with relativity as part of the population die of various other diseases and problems before developing cancer.

Many of the cancers seen in human beings are developed through external causes and are largely due to the environment in which they live, and their daily living habits. In cancers where the causes are known, smoking for the lungs and asbestos for the pleura, the risks are directely related to the exposure to cancerous substances.

The frequence of different types of cancer varies from country to country. Skin cancer for example is 200 times higher in Australia than India, oesophagus cancer 300 times higher in Iran than in Nigeria. Industrial countries suffer high levels of lung cancer due to the smoking habits of their population since many years.

Life styles and environment are strongly determinent in the appearance of cancer. This has been particularly noted with migrants. In time the migrant population tends to develop the same type of cancers found in the indigenous people of the welcoming country. The genetic constitution may play a role in the reaction of the organism to environmental factors. It is estimated that 5% of tumors are related to genetic problems.

In Switzerland, the most important cancer found in men is lung cancer, however the incidence of this cancer has diminished since the 1980's but has risen in women with their increased smoking habits. Lung cancer is closely followed by prostatic and colo-rectal cancer in men. With women, breast cancer is the most important followed by colo-rectal and lung cancer. In non smokers of both sexes, colo-rectal cancer is the most frequent.

During the last few years, an increase in breast and prostatic cancers has been discovered, probably due to investigatory campaigns. Cancers of the uterin cervix have however drastically decreased because of long years of successful investigation, allowing the lesions to be treated before degenerating into cancers.

Pour en savoir plus:

Levi F, Randimbison L, Te VC, Franceschi S, La Vecchia C: Trends in survival for patients diagnosed with cancer in Vaud, Switzerland, between 1974 and 1993. Annals of Oncology 11:957-963, 2000