One in eight women in the U.S. is diagnosed with breast cancer, making it the second-most-common cancer among women. The cause of breast cancer is linked to a variety of external risk factors in addition to natural factors that are typically out of a person’s control.
While some men get the disease, women are 100 times more likely to be diagnosed with it. The cancer may originate in either the part of the breast that produces milk or the ducts that transport the milk. Invasive forms of the cancer can spread to other tissues throughout the breast, while noninvasive breast cancer remains in one area.
Natural risk factors include gender, age, race, family history of breast cancer, genetic makeup and early onset of menstruation. According to a 2016 study, environmental factors play a role in the risk of breast cancer including exposure to ionizing and nonionizing radiation, pesticides, polycyclic aromatic hydrocarbons and metals.
Some studies have found higher rates of breast cancer among women exposed to asbestos, although the link between the two appears thin.
Asbestos is a carcinogen that has been linked conclusively to other health conditions such as mesothelioma cancer, but its exact correlation to breast cancer is uncertain. Although researchers have noted an elevated incidence of breast cancer in women who have been exposed to asbestos fibers, studies have not yet determined how asbestos directly affects breast tissue.
According to Dr. Debra David, many studies that have attempted to demonstrate a correlation between asbestos exposure and breast cancer fail to do so strictly because they do not achieve statistical significance, meaning there were not enough women involved in the study to make it statistically conclusive. Two international studies delivered different conclusions from each other.
One Australian study published in 2009 reviewed the potential association between exposure to blue asbestos and cervical, ovarian, uterine and breast cancers. Nearly 3,000 women from Wittenoom — the home of a large asbestos company operated until 1966 — were compared with the general Western Australian population. Cervical and ovarian cancers were slightly more prevalent in former factory workers and town residents than the general population. Breast cancer rates remained the same.
A similar study that monitored cancer diagnoses in British asbestos factory workers was the only one of its kind to suggest an association between occupational asbestos exposure and elevated rates of breast cancer. This project found a slightly increased rate of breast cancer diagnoses in female factory workers who experienced significant exposure over two or more years. The study expected 10.48 deaths from breast cancer, yet 12 participants passed away from the illness.
Another British study, ” Prevalence of Asbestos Bodies in a Necropsy Series in East London,” examined the lungs of 178 female participants for the presence of asbestos fibers. The mineral was present in 30 percent of all women in the study, yet the majority of this percentage was found in the subgroup of women who had been diagnosed with breast cancer. Of the 82 female participants with the illness, 38 were found to have asbestos in their lungs.
Authors within the study suggested that asbestos fibers may have reached the breast tissue through retrograde lymphatic flow from the lungs to the chest wall, while another study yielded another hypothesis. The second study implied that asbestos fibers may pierce the lungs and pass through the muscles that cover the chest wall, eventually reaching the breast tissue. While the evidence to support either suggestion is limited and does not speak to a causal relationship, the potential link between asbestos and breast cancer requires continued study to warrant any factual association.
In a 2011 study, the International Agency for Research on Cancer (IARC) evaluated more than 900 different agents and determined that no agents in the workplace, including asbestos exposure, were associated with breast cancer. Only night shift work was associated with breast cancer, which is likely connected to disruption of hormones or immune function.
According to the American Cancer Society, about 5 to 10 percent of breast cancer cases can be directly attributed to mutations of certain inherited genes, one example of how some factors are out of a cancer patient’s control. However, there are partial risk factors that can be linked to the formation of breast cancer that are within the control of an individual.
Karen Selby joined Asbestos.com in 2009. She is a registered nurse with a background in oncology and thoracic surgery and was the director of a tissue bank before becoming a Patient Advocate at The Mesothelioma Center. Karen has assisted surgeons with thoracic surgeries such as lung resections, lung transplants, pneumonectomies, pleurectomies and wedge resections. She is also a member of the Academy of Oncology Nurse & Patient Navigators.
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