What is Obesity?
An excessive amount of body fat is a characteristic of the medical condition known as obesity. The common definition is having a body mass index (BMI) of 30 or higher. Obesity is a major public health concern on a global scale. The number of overweight adults worldwide is approximately 1.9 billion, with over 650 million being labeled as obese. Obesity is a significant risk factor for several chronic diseases, including diabetes, heart disease, and stroke.
The Link Between Obesity and Cancer
Obesity has been linked to an increased risk of several cancers, including colorectal, postmenopausal breast, endometrial, renal, esophageal adenocarcinoma, pancreatic, and liver cancers. Studies show that the risk of cancer increases along with BMI. Obesity is also linked to worse outcomes for cancer patients, including a higher chance of recurrence, higher mortality rates, and a decreased response to treatment.
Pathophysiology
The relationship between obesity and cancer has been attributed to a variety of different processes. These consist of:
- Hyperinsulinemia and insulin resistance, which boost cell growth and prevent apoptosis.
- Elevated levels of some hormones, including leptin, IGF-1, and estrogen, which have been implicated with the onset and progression of specific forms of cancer.
- Pro-inflammatory chemicals and adipokines are produced by adipose tissue, an endocrine organ, which can lead to chronic inflammation and accelerate the development of cancer.
- DNA damage and increased oxidative stress.
Obesity has been linked to changes in the way hormones and metabolism are regulated, which may aid in the onset and spread of cancer. These modifications include:
- Elevated estrogen levels in postmenopausal women (because of the aromatization of androgens in adipose tissue).
- Increased insulin and insulin-like growth factor 1 (IGF-1) levels (which encourage cell development and prevent apoptosis).
- Certain malignancies, including endometrial cancer (which have been associated with hyperinsulinemia).
- Higher concentrations of adipokines, like leptin (which prevent apoptosis and encourage cell growth).
Inflammation and Stress
Obesity and cancer are thought to be linked by chronic low-grade inflammation and stress. Adipose tissue produces pro-inflammatory molecules that promote chronic inflammation and contribute to the cancer process. Oxidative stress and DNA damage may also aid cancer development and progression.
Cancer types with the strongest link to obesity:
- Colorectal cancer – and the risk is higher for people with a higher BMI.
- Postmenopausal breast cancer – especially in women who have never used hormone replacement therapy.
- Endometrial cancer – particularly in women who have not reached menopause.
- Renal cancer.
- Esophageal adenocarcinoma.
- Pancreatic cancer.
- Liver cancer – especially in people with nonalcoholic fatty liver disease (NAFLD).
Impact of Obesity on Survival and Recurrence
Obesity can have a negative impact on treatment outcomes in addition to increasing the risk of developing certain types of cancer. This includes a higher risk of recurrence and a lower chance of survival. It has also been linked to a reduced response to cancer treatments such as chemotherapy, radiation therapy, and targeted therapy. The reasons for this relationship are unknown, but they may involve obesity-related hormones, metabolic changes, and inflammation.
Obesity Management in Cancer
A healthy weight is essential for cancer prevention and management. Weight loss in obese or overweight people has been shown in studies to lower the risk of developing certain types of cancer as well as improving outcomes. The most appropriate weight loss interventions should be determined by the individual’s needs and cancer stage.
Obesity and cancer patients may benefit from bariatric surgery such as gastric bypass, sleeve gastrectomy, or adjustable gastric banding. Bariatric surgery has been proven in studies to result in substantial weight loss, which may reduce the risk of cancer development and recurrence. (bookbutchers.com) However, it is crucial to consult with a bariatric surgery and cancer treatment specialist to determine if this is a viable option for you.
To develop a weight management plan, cancer patients should consult with a registered dietitian. Reducing caloric intake, increasing protein intake, and following a diet low in saturated fat and added sugars are some nutrition and physical activity recommendations. Regular physical activity, such as brisk walking, is also advised to improve cancer outcomes and aid weight loss.
Weight loss interventions may have different safety and efficacy profiles in cancer patients than in the general population, so close monitoring and collaboration between the patient’s cancer care team and a registered dietitian or other weight management expert is essential to ensure the interventions’ safety and effectiveness. Furthermore, weight loss interventions may not be appropriate for some cancer patients, particularly those who are on chemotherapy, malnourished, or have advanced cancer.
