Smoking – Smoking is a major cause of many health problems and in modern societies it is the foremost preventable cause of cancers. Tobacco smoking is responsible for an increased incidence of cancers of the lung, mouth, throat and larynx as well as cancers of the oesophagus, stomach, pancreas, kidney, bladder, cervix uteri and in the long term even the breast. Sunshine – Excessive ultra-violet light from sunshine is predominantly responsible for a greatly increased incidence of skin cancers Other Forms of Irradiation: X-rays and Atomic Irradiation – Increased incidence of cancers in the skin of the hands in people who held X-ray plates in their hands during the early use of X-ray machines was the fi rst evidence that irradiation with X-rays would cause certain cancers. An increased incidence of other cancers, including thyroid cancer and leukaemias Hormones – Increased hormones or prolonged hormone exposure can be associated with increased risk of some cancers. There is an increased risk of breast cancer in women having hormone replacement therapy (HRT) for postmenopausal symptoms. Prostate cancer in men is known to be an androgen dependent tumour. Without androgens prostate cancer will not grow. Other cancers that are sometimes linked to hormones include cancer of the body of the uterus. Nutritional Deficiencies and Food Habits – Defi ciencies of certain vitamins, trace elements, anti-oxidants, naturally occurring plant hormones and other plant products including natural fibre have been Alcohol – The association between alcohol and cancer is not so clear. There is an obvious association in heavy drinkers, especially of strong spirits, with cancers in the oesophagus. The incidence of oesophageal cancer is signifi cantly increased in both heavy drinkers and tobacco smokers in any of its forms (whether it be cigarettes, pipes or cigars).
linked to increased risk of several cancers of different types, in different body systems and in different communities and racial groups often living in different parts of the world. High animal fat content of food appears to be associated with increased risk of some cancers; whilst a diet rich in fresh fruit and vegetables appears to be protective.