Breast cancer has become the most common type of cancer in the world, as per a new research, with deaths due to this disease expected to touch a million a year by 2040. It has many risk factors, including obesity, which is a condition that involves excess body fat. Obesity has often been associated with several health conditions, such as type 2 diabetes. It also has links with a higher chance of breast cancer. Considering the new research, let us take a look at the connection between obesity and breast cancer.

What does the new research on breast cancer say?

Breast cancer is now the most common type of cancer in the world, revealed an April 2024 report by the Lancet Commission. It was found that approximately 7.8 million women were diagnosed with this disease in five years till the last quarter of 2020. The commission expects cases related to breast cancer cases to increase from 2.3 million in 2020 to over 3 million by 2040 in the world. Deaths due to breast cancer are likely to hit a million a year by 2040, according to the commission.

What is breast cancer?

Breast cancer is a type of cancer that develops in a person’s breast cells. It usually begins in the milk ducts or the lobules, which are the glands that produce milk, explains oncologist Dr Manish Sharma. Some risk factors for breast cancer include age, family history, hormone replacement therapy, alcohol consumption, and obesity.

Does obesity increase breast cancer risk?

The chance of developing breast cancer goes up in post-menopausal women who are obese, as per an analysis published in the BMC Women’s Health in 2023. Obesity can increase the risk for breast cancer through various ways:

1. Hormonal changes

Adipose tissue or fat cells can produce estrogen, a hormone that plays a key role in the development and growth of certain types of breast cancer, such as estrogen receptor-positive (ER-positive) breast cancer, says the expert. In obese women, there is often an overproduction of estrogen due to increased fat tissue, which can promote the growth of breast cancer cells.

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2. Insulin resistance

Obesity is associated with insulin resistance, a condition in which the body’s cells become less responsive to the effects of insulin. Insulin resistance can lead to higher levels of insulin and insulin-like growth factor 1 (IGF-1) in the blood, which may promote the growth of cancer cells, including breast cancer cells.

3. Chronic inflammation

Obesity is characterised by a state of chronic low-grade inflammation, with elevated levels of inflammatory molecules in the bloodstream. Chronic inflammation can create an environment that promotes tumour growth and progression, including breast cancer.

4. Altered adipokine levels

Adipose tissue secretes various bioactive molecules called adipokines, which can have many effects on the body, including inflammation, metabolism, and cell growth. In obese women, the balance of adipokines is often disrupted, with higher levels of pro-inflammatory adipokines and lower levels of anti-inflammatory adipokines. These altered adipokine levels may contribute to the development and progression of breast cancer.

5. Changes in immune function

Obesity can affect the function of the immune system, leading to alterations in immune responses that may influence cancer development and progression. For example, obesity is associated with impaired immune surveillance, which may allow cancer cells to evade detection and elimination by the immune system, shares the expert.

6. Lifestyle factors

Obesity is often associated with unhealthy lifestyle factors, such as poor diet, lack of physical activity, and excessive alcohol consumption, which are themselves risk factors for breast cancer. These lifestyle factors may interact with obesity to further increase the risk for breast cancer.

Complications in obese women during surgery for breast cancer

Women who may be obese and undergo surgery for breast cancer could face complications due to their weight status. Some of these complications include:

1. Surgical complications

Obesity is associated with an increased risk of surgical complications, including wound infections, delayed wound healing, and dehiscence (wound reopening). The excess adipose tissue in obese women can make surgical procedures technically more challenging, leading to longer operative times.

2. Higher risk of anesthesia-related complications

Obesity is a known risk factor for anesthesia-related complications, such as respiratory complications (airway obstruction and hypoventilation), cardiovascular complications (hypertension and arrhythmia), and difficulty in administering anesthesia due to body habitus, says Dr Sharma. Anesthesia management in obese women requires careful consideration and may pose challenges for the anesthesia team.

3. Increased risk of blood clots

Obesity is a risk factor for venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE). Surgery itself, along with the immobilisation associated with the postoperative period, further increases the risk of blood clots.

What are the breast cancer treatment options for obese women?

The treatment options for breast cancer in obese women are generally similar to those for non-obese women. Here are some common breast cancer treatment options:

1. Surgery

Surgery is often a primary treatment for breast cancer and may involve either breast-conserving surgery (lumpectomy) or mastectomy. In obese women, surgical planning may need to take into account factors such as increased adipose tissue, which can affect the technical aspects of the procedure, as well as the potential for increased surgical complications.

2. Radiation therapy

Radiation therapy is commonly used after breast-conserving surgery to reduce the risk of local recurrence. In obese women, treatment planning for radiation therapy may need to consider factors such adipose tissue distribution to ensure accurate delivery of radiation, says the expert.

3. Chemotherapy

Chemotherapy may be recommended for certain breast cancer patients, particularly those with more aggressive or advanced disease. Obesity can influence chemotherapy dosing and drug metabolism. Oncologists may need to adjust chemotherapy doses based on factors such as body surface area or ideal body weight.

4. Hormone therapy

Hormone therapy, also known as endocrine therapy, is a treatment for hormone receptor-positive breast cancer. But obesity can affect hormone levels and metabolism, which may impact the effectiveness of hormone therapy.

Lifestyle modifications, including weight management, healthy diet and regular physical activity, can play a supportive role in breast cancer treatment.

Preventing obesity through lifestyle modifications and healthy habits can help reduce breast cancer risk.

So, try to maintain a healthy weight by working out, saying no to sedentary behaviour, practicing portion control and limiting consumption of high-calorie and high-fat foods.