5.3.3 Risk factors

The majority of cancers can be attributed to the particular environment in which an individual is living and his/her lifestyle. Here below we have the major risk factors for the cancer sites included in the present chapter.

Stomach cancer: It has been estimated that most cases of this cancer are preventable by appropriate diets and associated factors. Non-starchy vegetables, allium vegetables, and fruits protect against stomach cancer; salt and also salt-preserved foods are the causes of this cancer. There is strong evidence that infection with a certain bacteria, Helicobacter pylori, is associated to an increased risk of stomach cancer (WCRF, 2007).

Colorectal cancer: the evidence that physical activity protects against colorectal cancer is convincing, although the evidence is stronger for colon than for rectum. The evidence that red meat, processed meat, substantial consumption of alcoholic drinks (in men), body fatness and abdominal fatness, and the factors that lead to greater adult attained height, or its consequences, are causes of colorectal cancer is convincing. Substantial consumption of alcoholic drinks is probably a cause of this cancer in women. Foods containing dietary fibre, and garlic, milk, and calcium probably protect against this cancer (WCRF, 2007). Cancer control priority should be given to the promotion of those health determinants related to colorectal cancer aetiology, such as a healthy diet and physical activity.

Lung cancer: smoking is a primary cause of lung cancer, although pollution and exposure to certain gases/chemicals may also be influential. Geographic patterns of lung cancer incidence and mortality are influenced by past exposure to tobacco smoking, and the geographic pattern in women reflects the rather different historical patterns of smoking compared to men (Parkin et al, 2005). Although male lung cancer incidence is decreasing in all European macro-areas, lung cancer remains the first cancer diagnosed in men in Eastern and Southern Europe and the second in Western and Northern Europe. Therefore, awareness of tobacco as a risk factor promoting lung cancer is increasing, but the war against tobacco has not been won yet. To achieve this goal we need to make additional efforts For instance specific actions addressed to women and young people are needed.

Breast cancer: Breast cancer is hormone related, and the factors that modify the risk of this cancer when diagnosed pre-menopausally and when diagnosed (much more commonly) post-menopausally are not the same. Risk factors for breast cancer in women include the events of reproductive life and lifestyle factors ( e.g. unbalanced diet and alcohol) that modify endogenous levels of sex hormones (Key et al, 2002). Physical activity probably protects against breast cancer in post-menopause, and there is limited evidence suggesting that it protects against this cancer diagnosed in pre-menopause. The evidence that alcoholic drinks are a cause of breast cancer at all ages is convincing. The evidence that the factors that lead to greater adult attained height, or its consequences, are a cause of postmenopausal breast cancer is convincing, and these are probably also a cause of breast cancer diagnosed in premenopause (WCRF, 2007).

Cervical cancer: the main risk factor is the infection by some forms of genital human papilloma virus or HPV (Stewart and Kleihues, 2003). Genital HPV is usually spread by sexual contact. Abnormal cells, derived from HPV infection, take many years to progress into cervical cancer, and once detected early by screening via PAP-smear test, these cells can be easily removed so they do not develop into cervical cancer.

Prostate cancer: age is the strongest risk factor for prostate cancer: development of this malignancy is a multi-step process associated with a long natural history. Other certain risk factors are a diet rich of fat and family history, while possible risk factors are linked to androgens and race (Stewart and Kleihues, 2003).