Breast cancer is the most common cancer among Canadian women, with more than 23,000 new diagnoses annually . Incidence rose 1% per year from 1969 to 1999 (a 30% increase), but for all age groups, occurrence has since stabilized, albeit at rates that are among the highest in the world .
Breast cancer results from a complex, often interactive combination of genetic, hormonal/reproductive and environmental factors . An estimated 5 to 10% of breast cancers are hereditary . ‘Lifestyle’ factors such as diet and alcohol consumption contribute to higher incidence, as does prolonged exposure to one’s own estrogens, resulting from early age at menarche, late age at menopause, late age at first full-term pregnancy or nulliparity .
In March 2011, a UN scientific meeting concluded that cancers related to the environment comprise approximately 19 per cent of all cancers – nearly one in five . Environment risks include exposures to chemicals and radiation wherever they occur (home, schools, workplaces), trace elements in personal and consumer products, and/or in the environment-at-large. Individuals are usually involuntary exposed to these environmental risks.
The most extensive compilation to date on this topic is a U.S. report, State of the Evidence: The Connection Between Breast Cancer and the Environment (Sixth Edition, 2010), which includes references to scientific studies on hormones in pharmaceutical and personal care products, natural and additive hormones in foods, as well as endocrine-disrupting compounds (EDCs) such as Bisphenol A (BPA), phthalates, parabens, aromatic amines, pesticides, herbicides, and heavy metals. Non-endocrine disrupting industrial carcinogens such as benzene and vinyl chloride are additionally covered, as well as light-at-night/melatonin disturbance, and ionizing and non-ionizing radiation .