WHAT IS THE CAUSE OF BREAST CANCER?

Smoking is widely recognised for its role in causing various cancers, particularly lung cancer. The connection between smoking and breast cancer is less clear compared to other cancers, but research indicates that smoking may still be a risk factor. According to the Cancer Council Australia, while smoking is not the primary cause of breast cancer, it can contribute to an increased risk, especially in combination with other factors. The evidence suggests that:

Overall Risk Increase: Studies have shown that smoking may slightly increase the risk of developing breast cancer. This risk is particularly noted in women who smoke heavily or for prolonged periods.

Postmenopausal Women: Research suggests that smoking might have a more significant impact on the risk of breast cancer in postmenopausal women compared to premenopausal women.

Australian Research and Findings

Several Australian studies have contributed to understanding the link between smoking and breast cancer:

Australian Institute of Health and Welfare (AIHW): The AIHW reports that smoking is a known risk factor for many cancers, including breast cancer, though it is not as significant as factors like genetics and hormone exposure. Their reports emphasize that while smoking is not a major risk factor for breast cancer, it still poses a health risk.

Cancer Council Australia: According to the Cancer Council, smoking is linked to several negative health outcomes, including an increased risk of breast cancer. They note that the risk is compounded by other factors, such as hormone replacement therapy and a family history of breast cancer.

While advances in breast cancer treatments have improved survival rates considerably over the last 30 years, research shows that survivors of breast cancer are at higher risk of cardiovascular disease than individuals without a history of cancer. Breast Cancer Trials explored this topic further in a recent Q&A on ‘Breast Cancer and Heart Health’.

Concerns about deodorants and breast cancer often stem from the ingredients used in these products, such as aluminium compounds and parabens. Aluminium compounds are used in antiperspirants to block sweat ducts, while parabens are preservatives used in various cosmetics and personal care products.

1. Aluminium Compounds: There has been speculation that aluminium compounds might mimic estrogen, a hormone linked to breast cancer. Some researchers have hypothesized that these compounds could potentially disrupt hormonal balance and contribute to cancer development. However, the Cancer Council Australia states that there is currently no conclusive evidence linking aluminium in deodorants to breast cancer.
2. Parabens: Parabens are used to prevent microbial growth in cosmetics. Concerns have been raised due to their weak estrogen-like activity. Some studies have found parabens in breast cancer tissue samples, but this does not establish a direct causal link between parabens and breast cancer. According to the Australian Government Department of Health, the evidence is not sufficient to confirm that parabens in deodorants increase the risk of breast cancer.

Australian Research and Expert Opinions

Australian health organizations have assessed the claims and conducted research on this topic:

1. Cancer Council Australia: The Cancer Council highlights that while there have been various studies exploring the connection between deodorants and breast cancer, none have provided conclusive evidence of a direct link. They emphasize that more rigorous research is needed to establish any definitive association.
2. Australian Government Department of Health: According to the Department of Health, there is no substantial evidence from current studies to support the claim that deodorants or antiperspirants cause breast cancer. They review and monitor scientific research continuously to provide updated information on potential health risks.

Concerns about bras and breast cancer primarily stem from theories suggesting that bras might restrict lymphatic flow or increase estrogen exposure, potentially leading to cancer development. One of the more prominent theories suggested that bras could impede lymphatic drainage, leading to toxin buildup and increasing cancer risk. However, this theory lacks strong scientific backing.

Current Scientific Evidence

1. Research Findings: The majority of scientific research and reviews have not found a conclusive link between wearing bras and an increased risk of breast cancer. According to the Cancer Council Australia, comprehensive studies have not supported the claim that bras cause breast cancer. Their position is based on a lack of empirical evidence connecting bra use with breast cancer risk.
2. Australian Government Department of Health: The Department of Health also supports the view that there is no substantial evidence linking bra use with breast cancer. Their guidelines and health information focus on well-established risk factors such as family history, age, and hormonal factors.

Mammograms are a crucial tool in the early detection and diagnosis of breast cancer. A mammogram is an X-ray imaging technique used to detect abnormalities in breast tissue. The procedure involves compressing the breast between two plates to obtain clear images.

Concerns About Mammorams and Breast Cancer

The primary concern about mammograms causing breast cancer stems from the exposure to radiation. Mammograms do involve a small amount of radiation, and some have questioned whether this could increase the risk of developing breast cancer.

1. Radiation Exposure: The amount of radiation used in a mammogram is very low. According to the Cancer Council Australia, the benefits of detecting breast cancer early far outweigh the potential risks from this minimal radiation exposure. The amount of radiation is much lower compared to other types of medical imaging, and the risk of radiation-induced cancer from mammograms is considered extremely small.
2. Research Findings: Research has consistently shown that the risk of radiation-induced cancer from mammograms is very low. The Australian Institute of Health and Welfare (AIHW) reports that while radiation exposure is a factor, the current standards and technology used in mammography are designed to minimize risk. The overall evidence supports that the benefits of early detection through mammograms significantly exceed any potential risks.
3. Australian Government Department of Health: The Department of Health emphasizes that mammograms are an essential part of breast cancer screening programs and that the risk of causing breast cancer is negligible compared to the benefits of early detection. Regular screening helps in detecting cancers at an early stage when treatment is more effective.

Hormone Replacement Therapy (HRT) involves the administration of hormones, typically estrogen, progesterone, or a combination of both, to manage menopausal symptoms. The potential link between HRT and breast cancer has been a subject of significant research.

1. Increased Risk with Combined HRT: According to the Cancer Council Australia, evidence shows that using combined HRT (estrogen and progesterone) can increase the risk of developing breast cancer. This increased risk is generally associated with long-term use and tends to diminish after discontinuation of therapy.
2. Estrogen-Only HRT: The risk associated with estrogen-only HRT is less clear. The Australian Institute of Health and Welfare (AIHW) indicates that estrogen-only HRT may have a lower risk of breast cancer compared to combined HRT. However, the risk may still be slightly elevated, particularly with long-term use.
3. Australian Government Department of Health: The Department of Health advises that the use of HRT should be personalized based on individual health needs and risks. They recommend discussing the potential benefits and risks of HRT with a healthcare professional to make an informed decision.

Find out more about the risks and benefits of HRT

Stress is a common experience that can affect physical and mental health. Chronic stress, in particular, has been studied for its potential impact on various health conditions, including cancer. The question of whether stress directly causes breast cancer is complex and requires careful consideration of existing evidence.

1. Scientific Evidence: Current research does not support a direct causal link between stress and breast cancer. According to the Cancer Council Australia, while stress is known to affect overall health and can influence behaviours that may contribute to cancer risk (such as smoking or unhealthy eating), there is no clear evidence that stress directly causes breast cancer.
2. Stress and Hormonal Changes: The Australian Institute of Health and Welfare (AIHW) notes that stress can influence hormone levels in the body, which may affect cancer risk indirectly. For instance, stress can impact estrogen levels, but this relationship is not straightforward and does not establish a direct causal link between stress and breast cancer.
3. Australian Government Department of Health: The Department of Health acknowledges the role of stress in influencing overall health but emphasizes that established breast cancer risk factors include genetic predisposition, hormonal factors, and lifestyle choices rather than stress alone.

For more information, view our article: Can Stress Increase the Risk of Breast Cancer?

Botox, a brand name for botulinum toxin injections, is widely used in a range of cosmetic and other medical procedures. Botox is derived from the bacterium Clostridium botulinum and works by temporarily paralysing muscles to reduce wrinkles or treat certain medical conditions such as migraines or excessive sweating. The toxin is administered via injection into specific muscles or areas.

Concerns and Evidence

1. Lack of Direct Evidence: According to the Cancer Council Australia, there is no substantial evidence linking Botox to an increased risk of breast cancer. Botox is localized to the area where it is injected and is not known to spread throughout the body in a way that would increase cancer risk.
2. Safety Reviews: The Australian Government Department of Health states that Botox has been subject to extensive safety evaluations and monitoring. These reviews have not identified a direct link between Botox injections and breast cancer. The primary concerns with Botox relate to its potential side effects, such as localized muscle weakness or allergic reactions, rather than cancer risk.
3. Australian Therapeutic Goods Administration (TGA): The TGA, which regulates medicines and medical devices in Australia, monitors the safety of Botox and other similar products. According to their assessments, Botox is considered safe when used as directed, with no evidence suggesting a connection to breast cancer.

Prolia (denosumab) is a medication used to treat osteoporosis and certain types of bone cancer-related conditions. Prolia is a monoclonal antibody that targets and inhibits RANKL (Receptor Activator of Nuclear Factor Kappa-B Ligand), a protein involved in bone metabolism. By blocking RANKL, Prolia helps to prevent bone loss and strengthen bones, particularly in patients with osteoporosis or those undergoing cancer treatments that affect bone density.

Concerns and Evidence

1. Current Research: According to the Cancer Council Australia, there is no conclusive evidence that Prolia increases the risk of breast cancer. The primary focus of Prolia is on bone health, and while it has been studied extensively for its effects on bone density and fracture prevention, studies have not identified a direct link to breast cancer.
2. Safety Profile: The Australian Government Department of Health and the Therapeutic Goods Administration (TGA) monitor the safety of medications, including Prolia. Their reviews and reports indicate that while Prolia can have side effects such as infections or joint pain, there is no strong evidence linking it to an increased risk of breast cancer.
3. Australian Institute of Health and Welfare (AIHW): The AIHW provides data on cancer incidence and treatments but has not identified Prolia as a risk factor for breast cancer. Their resources focus on more established risk factors and treatment options.

In vitro fertilization (IVF) is a widely used assisted reproductive technology that helps individuals and couples conceive a child. IVF involves stimulating the ovaries to produce multiple eggs, which are then retrieved and fertilized in a laboratory. The resulting embryos are implanted into the uterus. IVF typically involves the use of fertility medications that increase hormone levels, such as estrogen and progesterone.

Evidence and Research

1. Current Findings: The Cancer Council Australia indicates that the relationship between IVF and breast cancer risk is not well established. While IVF involves hormone treatments, current research does not provide strong evidence that IVF directly increases the risk of breast cancer. Studies have produced mixed results, with some showing no increased risk and others indicating a potential slight increase, particularly with prolonged use of fertility treatment.
2. Australian Institute of Health and Welfare (AIHW): According to the AIHW, research into the long-term health effects of IVF is ongoing. Their reviews suggest that while there may be some concern about the impact of fertility drugs on hormone levels, the overall evidence linking IVF to breast cancer remains inconclusive.
3. Australian Government Department of Health: The Department of Health provides guidelines on IVF and fertility treatments but notes that there is no substantial evidence to suggest that IVF directly causes breast cancer. They recommend that individuals undergoing IVF discuss potential risks and benefits with their healthcare provider.

Cellphones emit radiofrequency electromagnetic fields (RF-EMFs) when in use, which are a form of non-ionizing radiation. Unlike ionizing radiation (such as X-rays), non-ionizing radiation does not have enough energy to remove tightly bound electrons or damage DNA directly. The primary concern is whether long-term exposure to RF-EMFs could influence cancer risk.

Evidence and Research

1. Current Scientific Consensus: According to the Cancer Council Australia, the majority of scientific studies and reviews have not found a clear link between cellphone use and breast cancer. Research on RF-EMFs and cancer is ongoing, but so far, there is no consistent evidence suggesting that cellphone use increases breast cancer risk. The Cancer Council emphasizes that more research is needed to understand any potential long-term effects.
2. Australian Government Department of Health: The Department of Health reviews and monitors radiation exposure and health risks. They note that while RF-EMFs from cellphones are classified as non-ionizing radiation, which is less harmful compared to ionizing radiation, current evidence does not support a definitive link between cellphone use and breast cancer. The Department of Health supports continued research in this area to ensure public safety.
3. Australian Institute of Health and Welfare (AIHW): The AIHW provides data and research on various health issues, including cancer. Their reviews indicate that while concerns about cellphone radiation exist, there is no conclusive evidence from current studies linking cellphone use to an increased risk of breast cancer.

Flaxseeds are often touted for their health benefits, including their potential to support heart health and digestive function. They are rich in omega-3 fatty acids, fiber, and lignans, which are plant compounds with antioxidant properties. Given their content, particularly lignans, there is interest in understanding whether flaxseeds might influence breast cancer risk.

Evidence and Research

1. Current Scientific Consensus: According to the Cancer Council Australia, there is no substantial evidence linking flaxseeds directly to an increased risk of breast cancer. In fact, some research suggests that flaxseeds might have protective effects against certain types of cancer due to their high content of lignans and omega-3 fatty acids.
2. Australian Institute of Health and Welfare (AIHW): The AIHW reports that while lignans have estrogen-like effects, they are weak compared to human estrogen. Some studies suggest that lignans may even have a protective effect against breast cancer by modulating estrogen metabolism and reducing inflammation. 
3. Australian Government Department of Health: The Department of Health supports a balanced approach to nutrition and acknowledges that flaxseeds, as part of a varied diet, are not linked to increased breast cancer risk. Their guidelines emphasize the importance of overall dietary patterns rather than focusing on individual foods.

Collagen is a protein found in the connective tissues of the body, including skin, bones, and cartilage. Collagen supplements are typically derived from animal sources like bovine, porcine, or marine collagen and are marketed to support skin health, joint function, and overall vitality.

Evidence and Research

1. Current Scientific Consensus: According to the Cancer Council Australia, there is no substantial evidence to suggest that collagen supplements are associated with an increased risk of breast cancer. Collagen supplements are primarily composed of proteins and do not contain known carcinogens or compounds linked to cancer.
2. Australian Institute of Health and Welfare (AIHW): The AIHW emphasizes that while there is ongoing research into the effects of various dietary supplements, including collagen, there is currently no direct evidence linking collagen supplements to breast cancer. The AIHW suggests that while some supplements may impact health, they do not appear to be significant risk factors for cancer.
3. Australian Government Department of Health: The Department of Health provides guidelines on dietary supplements and notes that while collagen supplements are widely used, there is no evidence linking them directly to an increased risk of breast cancer. Their guidelines stress the importance of a balanced diet and caution against relying solely on supplements for health benefits.

Breast reduction surgery involves the removal of excess breast tissue, fat, and skin to achieve a breast size more proportionate to the body. The procedure aims to alleviate physical symptoms such as back pain, shoulder pain, and skin irritation caused by large breasts.

Evidence and Research

1. Current Scientific Consensus: According to the Cancer Council Australia, there is no evidence to suggest that breast reduction surgery increases the risk of breast cancer. The procedure is primarily aimed at reducing breast size and does not involve the removal or alteration of the breast tissue in a manner that would increase cancer risk.
2. Australian Institute of Health and Welfare (AIHW): The AIHW reports that breast reduction surgery does not have a known direct effect on breast cancer risk. The surgery itself is not associated with an increased likelihood of developing breast cancer. The focus is on alleviating symptoms rather than affecting cancer risk.
3. Australian Government Department of Health: The Department of Health provides information on various medical procedures and confirms that there is no established link between breast reduction surgery and breast cancer. They stress that breast reduction surgery is a common procedure for improving quality of life and reducing physical discomfort.

Breast implants are medical devices placed under the breast tissue or chest muscle to increase breast volume. They come in various types, including saline-filled and silicone gel-filled implants. The primary purposes of breast implants are cosmetic enhancement and breast reconstruction after cancer surgery.

Evidence and Research

1. Current Scientific Consensus: According to the Cancer Council Australia, there is no conclusive evidence to suggest that breast implants increase the risk of breast cancer. The organization notes that breast implants themselves do not directly cause breast cancer. However, the presence of implants can make it more challenging to detect breast cancer through mammography.
2. Australian Government Department of Health: The Department of Health indicates that while breast implants are not associated with an increased risk of breast cancer, they can complicate mammographic imaging. Implants can obscure breast tissue and make it more difficult to identify potential tumours during screening. Therefore, additional imaging techniques or specialized mammography may be required.
3. Australian Institute of Health and Welfare (AIHW): The AIHW reports that there is no direct evidence linking breast implants to an increased risk of breast cancer. They acknowledge that while implants do not increase cancer risk, women with implants should be aware of potential challenges in breast cancer detection and should communicate with their healthcare providers about appropriate screening strategies.

Find out more on this topic in our article on Common Breast Cancer Myths and Facts and breast implant-associated anaplastic large cell lymphoma.