What is the Relationship Between Breast Cancer, Obesity and Health Disparities?
— By Dawn M. Sweet, Ph.D
Breast cancer is the most prevalent form of cancer in women. Weight loss is one tool to mitigate side effects and complications.
Breast cancer has surpassed lung cancer as the most prevalent form of cancer in women.1 After menopause, adipose tissue is the predominant site of estrogen production; consequently, women with obesity exhibit greater postmenopausal estrogen levels and as a result, an increased exposure to the protumorigenic effects of estrogen.2 This makes obesity-mediated exacerbation of cancer a concern for women with obesity. For all subtypes of breast-cancer, women with obesity tend to develop larger primary tumors when initially diagnosed and an increased risk of developing lymph-node metastases. Obesity can expedite and exacerbate metastatic progression2, and women of color with obesity are at greatest risk.
Women with Obesity and Health Disparities
A 20203 study found that despite the incidence of breast cancer being relatively similar among non-Hispanic White women and non-Hispanic Black women, non-Hispanic Black women are estimated to be 40 percent more likely to succumb to breast cancer compared to non-Hispanic White women. Additionally, their five-year survival rate is 78.9 percent compared to 88.6 percent for non-Hispanic White counterparts.
Research suggests the racial disparities can be attributed to several factors such as social determinants of health care access to tumor biology and comorbidities.2 Among patients with obesity, an elevated BMI is more pronounced in non-Hispanic Black patients compared to other races and ethnic groups. For example, among non-Hispanic Black women, 56.9 percent were patients with obesity compared to only 39.8 percent of non-Hispanic White counterparts. Thus, researchers2 suggest that obesity could be a causal contributor to the racial disparities found in breast cancer patients.
While several biologically-based links between obesity and racial differences exist, the outcomes cannot be explained by biology alone.2 For example, a 20154 study reported that there are obesity-related delays to screening due to biases may contribute to the increased incident of breast cancer in women of color with obesity. Non-Hispanic Black women are more likely to be diagnosed later than non-Hispanic White counterparts, thereby leading to a delay in treatments and progression of the cancer. The relationship between race and obesity and subsequent biases may be prognostically detrimental for many women of color with obesity.
Diet as a Way to Mitigate Racial Disparities
A 20175 found a correlation between a patient’s BMI at diagnosis and recurrence of breast cancer. For women with obesity, side effects from treatment are reported to be more pronounced as are risks of complications. Women with lower BMIs are less susceptible to side effects and complications, though neither can ever be completely eradicated despite one’s BMI.
Weight loss is one tool to mitigate side effects and complications. Researchers found that cancer cells are sensitive to restricting nutrients, thus dietary interventions such as calorie-restricted diets represent a cost-effective and generally efficacious strategy for treating breast-cancer patients with obesity. Caloric restrictions can manipulate the availability of nutrients for tumors.6
Clinicians should consider supervised calorie-restricted diets such as Very Low Calorie Diets (VLCD) or Low Calorie Diets (LCD) in breast cancer patients with obesity as part of their clinical management plan. Additionally, clinicians should take note of the racial disparities observed in breast cancer diagnosis and treatment and manage clinical care with these disparities in mind.
- Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries
The obesity-breast cancer link: a multidisciplinary perspective
- Detection of crown-like structures in breast adipose tissue and clinical outcomes among African-American and White women with breast cancer
- Obesity and cancer: Mechanistic insights from transdisciplinary studies
- Recurrence dynamics of breast cancer according to baseline body mass index
- Fasting and cancer: Molecular mechanisms and clinical application