Breast cancer is the most common cancer in women both in the developed and less developed world. It is estimated that worldwide over 508 000 women died in 2011 due to breast cancer (Global Health Estimates, WHO 2013). Incidence rates vary greatly worldwide from 19.3 per 100,000 women in Eastern Africa to 89.7 per 100,000 women in Western Europe. In most of the developing regions the incidence rates are below 40 per 100,000 (GLOBOCAN 2008).
Risk factors are being understood for such a widespread disease that is turning into a chronic condition for the survivors. It is hard to pinpoint specific risk factors for cancer due to its long incubation period. Some feel powerless to prevent it as many of the risk factors seem to be decided before birth. Genetic factors do have a huge impact on people’s risk of a breast cancer prognosis, and it has long been thought that these factors are almost always outside of one’s control. Recent research though has renewed hope with contradicting results and that is what this paper is going to talk about. The risk of breast cancer and in turn its incidence can be brought down by modifying lifestyle choices. In this paper I will discuss the research conducted on the effect of lifestyle choices on the risk of breast cancer.
The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) has estimated that over 40% of post-menopausal breast cancer could be prevented by reductions in alcohol, excess body weight, and inactivity. Smoking, exposure to toxins dietary nutrient adequacy and fertility treatments in women also contribute to increased risk.
· Excess body weight
Positive energy balance, as a consequence of excess caloric intake and/or insufficient energy expenditure, results in increased adipose tissue leading to overweight and/or obesity. Strong observational data indicate that weight gain in the premenopausal period and being overweight or obese after menopause increase breast cancer risk. There is a well-established relationship between the two diseases, with most epidemiological studies demonstrating an increased risk of developing post-menopausal breast cancer in overweight or obese women.
· Physical Inactivity
A recent review of 73 observational studies indicated that moderate to vigorous PA reduces breast cancer risk by an average of 25% in pre- and post-menopausal women compared with inactive women. Both obesity and physical inactivity increase the risk of breast cancer development in older women and progression at all ages. Increased risks for overall mortality and breast cancer-specific mortality associated with increasing body mass index
Large systematic review and meta-analysis found a 28% increase in breast cancer-associated mortality in those who were current smokers compared to never smokers. The mortality in former smokers was equal to the one found in never smokers. This indicates that breast cancer patients ceasing to smoke can lower their risk of dying from their breast cancer disease dramatically, and possibly regain the risk of a never smoker.
· Alcohol intake
Women with the highest alcohol intake (of at least 27 units per week) were 51% more likely to develop breast cancer compared with non-drinkers. These studies suggest that women who want to minimize their breast cancer risk should not be drinking more than one unit daily and probably have at least two alcohol-free days weekly.
· Toxicant Exposure
Toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. There was a significant and progressive rise in the incidence of breast cancer in the decades following World War II , the same decades that saw exponential increases in the use of chemicals for production of pesticides, herbicides, plastics, cosmetics and other commonly used materials and products.
Between 1938 and 1971 millions of fetuses were exposed to the synthetic estrogen, diethylstilbestrol (DES), when their pregnant mothers were prescribed the drug. DES exposure was also associated with an increased risk of breast cancer in the mothers. In a follow-up study of daughters who were exposed prenatally to DES, a nearly twofold increase in breast cancer risk was observed in women older than age 40.
Higher maternal dichlorodiphenyl-trichloroethane (DDT) levels were associated with an almost 4-fold increase in occurrence of breast cancer in their daughters by age 52. Numerous studies have demonstrated an increased risk of breast cancer in women using oral contraceptives. The risk for breast cancer is greatest among current and recent users of oral contraceptives, particularly those who have used them for more than 5 years and initiated use at a young age.
· Fertility Treatment
Two studies found increased risk of breast cancer for women who have been treated for ovarian infertility with drugs including gonadotropins or clomiphene citrate. However, the results were significant only when the incidence of breast cancer was compared with the general population of women, but not with the more appropriate control of women with ovarian infertility who have not been treated with fertility drugs. Placental extracts, probably with high concentrations of progesterone 197 and estrogenic chemicals 198 are sometimes used in cosmetics and hair care products, particularly products marketed to women of color ,recently it has become clear that long-term exposures to progesterone can also influence the possible development of breast cancer.
Lifestyle changes are hugely important not only for those at low risk, but for those at high risk. There are important lessons to be learned. These results should encourage us that genetics do not determine everything about our health. Changes in lifestyle can overcome much of the risk our DNA imposes. All this research points in the same direction and indicate the importance of lifestyle throughout the lifespan and the challenge of finding ways to support women to achieve healthy ways of life