Chemotherapy Can Lead to Weight Gain For Patients with Breast Cancer

Chemotherapy can affect gut health, thereby leading to increased weight gain in patients with breast cancer, recent research found.

Associations between chemotherapy and weight gain have been confirmed for patients with early-detected breast cancer, according to a recent study. Specifically, chemotherapy treatment can lead to bacterial changes in the gut and unhealthy weight gain, which can further lead to higher risk of morbidity and reduced quality of life, according to a study from BMC Medicine.

The authors of the study noted that patients with breast cancer who received chemotherapy commonly have side effects such as fatigue, depressive symptoms, anxiety and peripheral neuropathy (pain or numbness in the hands and feet). However, weight gain was a recent finding among breast cancer survivors, as chemotherapy affected metabolic function, which increased risk of diabetes, hypertension (high blood pressure) and resultant cardiovascular risk, as reported in the study.

The study included 40 patients with surgically resected (cancer that is surgically removed) early-stage breast cancer, with data analyzed based on the types of therapy the patients received in addition to surgery. Ten patients received only adjuvant (additional treatment given after initial treatment such as surgery) chemotherapy, eight patients received only adjuvant endocrine therapy, 18 patients received chemotherapy followed by endocrine therapy and four patients only received surgery.

From the results of the study, the authors found that patients treated only with chemotherapy had an increase in weight (0.15% total mass per month), compared with patients who received only endocrine therapy and had a mean loss of weight at 0.19% total mass per month.

Another significant focus within the study was the gut microbiota (microorganisms that live in the digestive tract), as the authors hypothesized associations between chemotherapy-induced weight gain and the gut microbiota. They also delved into inflammation in the colon and its relationship to the gut microbiota.

The authors found that chemotherapy caused temporary weight gain and confirmed that weight gain was associated with a post-chemotherapy change in the gut microbiota and led to inflammation. With these factors in consideration, the authors suggested that there could be future treatments created to improve long-term outcomes for patients regarding the prevention of chemotherapy-induced physiological changes.

The authors of the study focused on three factors related to chemotherapy-related weight gain: patient age, menopausal status and lack of exercise. Regarding patient age, the study established that the group of patients treated with only chemotherapy had 18 patients younger than age 60 and ten were older than age 60. Eleven patients were pre-menopausal and 17 patients were post-menopausal. With this category, the authors stated that there was a “relative increase in weight gain in younger, pre-menopausal patients, a finding that was consistent across (their) entire patient cohort, but one which was especially pronounced in patients receiving chemotherapy.”

Within the study, each patient was classified by their weight based on body mass index (BMI) and the authors found that of the 40 participants in the study, 14 patients were considered normal weight, 10 were considered overweight and 16 patients were considered obese.

Post-treatment weight gain among patients with breast cancer, the authors stated, increases the risk of obesity and affects the risk of disease recurrence and death.

The findings from the study emphasized that weight gain from chemotherapy in patients with early-detected breast cancer may be temporary yet concerning. The authors urged that if chemotherapy caused a body-fat percentage increase and not just a change in weight, then there was a potential risk of increased long-term health issues, regardless of whether the patient returned to their pre-chemotherapy weight.

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