How Weight (BMI) Impacts Breast Cancer Risk in BRCA Mutation Carriers
Individuals with BRCA1 and BRCA2 gene mutations put people at a higher risk of developing breast and ovarian cancer. A recent research article by Bhardwaj et al., sheds light on the impact of Body Mass Index (BMI) on breast cancer risk for BRCA mutation carriers.
Obesity, (having a BMI of 30 or higher), is a known risk factor for breast cancer among women in the general population after menopause. However, for women with a BRCA1 or BRCA2 mutation, the relationship between BMI and breast cancer risk has been unclear due to conflicting findings in previous studies.
How a High BMI impacts Breast Tissue
In the study, researchers investigated the impact of BMI on the breast tissue of BRCA mutation carriers. They found a positive correlation between BMI and DNA damage in normal breast epithelial cells in high BMI individuals. In other words, a higher BMI increases DNA damage, potentially also increases the risk of breast cancer.
The researchers further explored the mechanisms behind this link. They discovered that obesity-associated factors, such as estrogen biosynthesis, are activated in the breast adipose microenvironment of BRCA mutation carriers. These alterations affected neighboring breast epithelial cells, contributing to increased DNA damage.
Benefit of Estrogen Therapy
Estrogen, a hormone known to play a significant role in breast cancer development, is influenced by obesity-associated factors. In breast tissue explants cultured from BRCA mutation carriers, blocking estrogen biosynthesis or estrogen receptor activity reduced DNA damage. This suggests that targeting estrogen may have a protective effect against breast cancer in this higher-risk population.
Potential Targeted Therapies
The study also explored the impact of other obesity-associated factors, such as leptin and insulin. These factors increase DNA damage in BRCA heterozygous epithelial cells. However, inhibiting the signaling of these factors with specific interventions decreased DNA damage. This opens up potential avenues for reducing breast cancer risk in BRCA mutation carriers through targeted therapies.
To strengthen their findings, the researchers conducted experiments on mice. They found that increased adiposity (body fat) was associated with mammary gland DNA damage and increased tumor development, further supporting the connection between BMI and breast cancer risk.
The results of this study support the link between elevated BMI and breast cancer development in BRCA mutation carriers. Therefore, maintaining a healthy body weight is particularly important for reducing breast cancer risk in this population. Additionally, pharmacologically targeting estrogen or metabolic dysfunction may offer possible preventive strategies.
This study brings us valuable insights into reducing breast cancer risk for individuals with BRCA mutations. By maintaining a healthy weight, avoiding processed foods, and exploring targeted interventions, BRCA mutation carriers can take proactive steps towards better breast health.
Weight-loss Surgery May Decrease Breast Cancer Risk
According to US Centers for Disease Control and Prevention (CDD), obesity is associated with an increased risk for 13 types of cancer, including breast cancer.
For individuals at high risk for developing breast cancer, maintaining a healthy lifestyle and BMI is important for reducing the likelihood of developing the disease. In some situations, weight loss surgery may be a good option to help reduce the overall risk.
According to a new study presented by Cleveland Clinic Florida researchers at the 36th American Society for Metabolic and Bariatric Surgery (ASMBS) Annual Meeting at ObesityWeek 2019, weight loss surgery cut the overall risk of developing cancers linked to obesity by 20%. In fact, women with obesity and known genetic susceptibilities for breast cancer were 2.5 times more likely to develop breast cancer than women with the same genetic risk who underwent weight loss surgery.
“Our findings suggest bariatric surgery could significantly prevent the development of cancer in patients with a higher risk than the average population, even in those genetically predisposed,” said study co-author Emanuele Lo Menzo, MD, Ph.D., FASMBS, Associate Program Director, General Surgery Residency Program, Cleveland Clinic Florida in Weston. “The effect we saw on patients genetically predisposed to developing breast cancer was remarkable and we believe this is the first time a study has shown such an impact. Further studies are needed to determine the factors, including weight loss, that may have led to such risk reduction.”
It is interesting to note that a similar study of patients with severe obesity (BMI of 35 or higher) published in Annals of Surgery earlier this year showed weight-loss surgery was associated with a 33% decrease in the risk of developing any type of cancer, and a 40% decrease in the risk of being diagnosed with a cancer associated with obesity.
It is important to remember, even individuals with a healthy BMI are still at risk for developing cancer. The importance of achieving and maintaining a healthy weight is to reduce the likelihood of developing breast cancer – unfortunately, it is NOT guaranteed prevention.
If you struggle to maintain a healthy weight, you are not alone! In fact, maintaining a healthy weight is a challenge for most adults today. The CDC reports more than 70% of American adults are overweight.
Maintaining a healthy weight is also very important after breast cancer treatment to decrease the risk of a recurrence. However, add the impact of a breast cancer diagnosis and the side-effects of some treatments, losing weight after breast cancer is typically even harder. Weight loss surgery may therefore also be an option for some survivors to consider if all other options have been exhausted.
Most people know that calorie control and regular exercise are crucial in losing and maintaining weight, but few people realize 80% of weight loss is achieved through better food choices. Even when we think we’re doing well by choosing the salad, we don’t realize the dressing has more calories than a Big Mac! A consultation with a nutritionist or dietician is a very good place to start your weight loss journey, and can provide extremely useful guidance in planning healthier meals.
