Reasons for Weight Gain After Breast Cancer Therapy - A Discussion

How Does Cancer Therapy Lead To Weight Gain?

Many people are surprised when the number on the scale starts going up during cancer treatment. But weight gain is actually a very common side effect, and it often begins within the first year after diagnosis.

Cancer therapy affects hormones, metabolism, appetite, and activity levels all at the same time, leading to unavoidable weight gain.

1. Chemotherapy slows the body down and does much more than fight cancer cells.

This includes:

• It causes the body to retain fluid, leading to swelling and bloating.

• Causes extreme fatigue, making exercise difficult.

• Trigger food cravings, especially when nausea is present.

• Slow metabolism, so fewer calories are burnt.

• Causes early menopause in some women, which naturally slows fat burning.

Some chemotherapy combinations, such as CMF (Cyclophosphamide, Methotrexate, Fluorouracil), when used with steroid-like Prednisolone, result in 17.6 to 22 pounds of weight gain within two years.

Drugs like Doxorubicin and Cyclophosphamide are also linked with noticeable weight gain.

2. Hormonal therapy changes fat distribution. Hormonal treatments used in breast, prostate, uterine, and testicular cancers lower levels of hormones like estrogen, progesterone, and testosterone. When these hormones drop, the body stores more fat and decreases muscle mass. Most women taking Tamoxifen report steady weight gain, and it is even more so when hormonal therapy is combined with chemotherapy.

3. Steroids increase appetite and belly fat. Steroids are often given to reduce nausea, control swelling, and prevent chemotherapy side effects. But these steroids have some effects on you, such as:

• Increased hunger.

• Promote fat storage around the belly.

• It causes rounding of the face and neck.

• Reduce muscle in the arms and legs.

Even short-term steroid use, along with reduced activity from fatigue or pain, adds extra pounds.

4. Early menopause makes it harder to control weight. In younger women, chemotherapy stops periods suddenly, a condition called 'chemotherapy-induced amenorrhoea'. Menopause symptoms in breast cancer result in a hormonal shift, causing slower metabolism and increased fat storage. A 2011 Australian study found that 43% of women were premenopausal at diagnosis, and these women gained more weight than those already in menopause.

What Are the Ill Effects of Weight Gain in Cancer Patients?

Even though much cancer guidance focuses on weight loss and malnutrition, gaining excess weight during or after cancer treatment also causes real health problems for survivors. Some ill effects of weight gain in cancer patients are:

1. Higher Risk of Poorer Cancer Outcomes:

Studies show that significant weight gain after a cancer diagnosis, especially in breast cancer, is linked with higher all-cause mortality rates and possibly a higher risk of cancer coming back compared with maintaining a stable weight. Large weight gains are strongly associated with these risks.

Weight gain during chemotherapy has been associated with shorter disease-free and overall survival in some breast cancer patient studies, possibly because it leads to lower relative drug dosing and worse metabolic health.

Excess fat tissue alters hormones like estrogen and insulin, creates chronic inflammation, and potentially promotes tumor growth and recurrence. This is a common side effect after hormonal therapy.

2. Metabolic and Health Complications:

Breast cancer therapy increases the risk of chronic diseases. Carrying extra weight raises the risk of type 2 diabetes (high blood sugar when your body does not use insulin effectively), hypertension (high blood pressure), heart disease, and stroke (a sudden blockage of blood flow to a part of the brain). Excess fat leads to higher insulin and insulin-like growth factor levels, which interfere with the effectiveness of cancer therapy and promote cancer cell growth.

3. Lower Physical Function and Quality of Life:

Gaining weight, especially when it is mostly fat, reduces physical activity, increases fatigue, and makes everyday tasks more difficult. Some cancer survivors gain fat while losing muscle, which weakens strength and stamina.

4. Emotional and Psychological Impact:

Weight gain after cancer therapy leads to negative body image, depression, and anxiety, leading to less recovery motivation. It also brings social attitudes and stress that affect mental health and social participation.

Do Breast Cancer Medications Cause Weight Gain?

Some breast cancer treatments are linked with weight gain, but the drugs themselves usually are not the main direct cause. Instead, weight gain tends to come from the combined effects of breast cancer treatment and lifestyle changes. Large studies have found no significant direct weight gain caused by Tamoxifen compared with no treatment. Some reports list weight gain as a possible side effect, but major studies do not support a clear causal link.

Aromatase inhibitors are known to affect hormone levels, which may favour fat storage, but evidence does not prove they directly make patients gain large amounts of weight.

What Are the Risks of Gaining or Losing Pounds?

During cancer treatment, the body is already under a lot of stress. Big weight changes, either gain or loss, may make things harder.

• Risks of Gaining Weight: Putting on extra kilos is not just about looks; it affects health. Weight gain increases the chance of the cancer coming back. Extra weight raises the risk of diabetes, heart problems, and high blood pressure. Often, the body gains fat but loses muscle, which makes you feel weak and tired even though the scale is larger.

• Risks of Losing Weight: Losing weight during treatment is even more dangerous. The body may not get enough nutrients, leading to poor immunity and slow healing. Treatments become harder to tolerate, causing dose delays or breaks. Daily tasks start to feel exhausting as the body loses strength and energy.

What Should I Eat During My Treatment?

To support your health and manage weight changes, focus on nutritious foods you enjoy. Some foods that you can eat are:

1. Try fibre-rich options like fruits, vegetables, whole-grain breads, cereals, and pasta.

2. Include protein from fish, lean meats such as chicken, turkey, or trimmed beef and pork, and plant-based proteins like beans, tofu, nuts, and seeds.

3. Choose low-fat dairy like skim or one percent milk, yogurt, or cheese.

4. Foods you enjoy are important too; feeling satisfied helps you stick to healthy eating.

Limit foods that contribute to weight gain or fluid retention. This includes:

1. Use less fat in cooking, reduce salt, and cut back on sugary drinks like soda or fruit juice.

2. Avoid or limit alcohol.

3. If steroids cause swelling, watch sodium in foods like long-life breads, sauces, dressings, cheese, deli or canned meats, olives, frozen meals, canned foods, table salt, and salty seasonings.

Other tips to manage weight include:

1. Planning meals and snacks by keeping healthy foods handy.

2. Eating only when hungry.

3. Finding activities you enjoy instead of eating out of boredom.

4. Eat slowly and try smaller portions using smaller plates.

5. Daily exercise and keeping a food diary help you track what works best for your body.

Conclusion:

Weight gain after breast cancer treatment is common and happens for several interconnected reasons. Chemotherapy, hormonal therapy, and steroid medications slow metabolism, change hormone levels, increase fat storage, and reduce muscle mass.

In younger women, chemotherapy causes early menopause, which further slows metabolism and promotes fat gain.

Focusing on healthy foods, gentle activity, and self-care helps manage weight and improve treatment outcomes. If you want to learn more about weight gain after breast cancer treatment, ask a specialist doctor.

Key Takeaways:

1. Weight gain after breast cancer treatment is common and results from a combination of therapy-related, hormonal, and lifestyle factors.

2. Breast cancer treatments slow down metabolism, change hormone levels, and reduce muscle mass. Treatment-related fatigue and stress often lead to reduced physical activity and increased food cravings.

3. Early menopause also contributes to weight gain, with studies showing that patients gain up to 17.6 to 22.0 pounds within two years of treatment.