Cancer is one of the world’s biggest killers, with over 7 million deaths caused by cancer across the globe each year. In the UK over 120,000 people die from cancer each year; cancer is currently the cause of 1 in 4 deaths in this country.
What is cancer?
Cancer is a condition which is caused by abnormal cell activity; cancer causes a mutation in the DNA, which causes the cells to reproduce quickly and grow much larger than normal cells. When cancerous cells multiply intensively they often form a tumour; tumours may sometimes be visible or tangible but often they are detected by scans and x-rays.
How does cancer spread?
Cancer spreads because it affects the normal behaviour of two genes in the body: the tumour suppresser gene and the oncogene. Cancer causes the oncogene (the gene responsible for stimulating cell growth) to work much more intensively than usual at the same time as slowing down the activity of the tumour suppresser gene; the combination of these changes makes it possible for cancer to spread to other parts of the body. Usually, cancer spreads through the lymphatic system; this can enable any part of the body to become affected by cancer.
Causes of cancer
The changes in the DNA of the cell can be brought about by several different factors; some of these include:
- Carcinogens: carcinogens are harmful substances or chemicals that have been proven to cause the genetic mutation characterised by cancer. The most common examples include smoke from tobacco and asbestos.
- Infectious diseases: infectious diseases, such as those caused by the HPV (Human Papillomavirus) can contribute to cancer; this is most common in cases of cervical cancer. Other infectious disease include Hepatitis A and B which commonly cause cancer of the liver and Epstein Barr virus which is commonly associated with cancers that affect the lymphatic system.
- Environmental factors: exposure to certain environmental conditions or radiation can contribute to cancer; skin cancer is one of the most common examples of this as it is caused by harmful UV rays.
- Hormone imbalances: changes in hormone levels can cause the DNA in the cells to be affected. Breast cancer in women that have had the menopause is sometimes caused by imbalances in hormone levels in the body.
- Health conditions which cause the immune system to become compromised: when the immune system is compromised the body is at greater risk of a number of harmful health conditions including cancer. Cancers including lymphoma and Karposi’s sarcoma are often diagnosed in people with suppressed immune systems.
Other risk factors include family history (especially in female cancers such as breast and ovarian cancers and male cancers including testicular and prostate cancer) and lifestyle choices (eating a poor diet, being overweight and drinking and smoking regularly all increase the likelihood of suffering from cancer.