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October 22, 2018
Breast Cancer & Weight Gain: What You Need To Know
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Breast Cancer & Weight Gain: What You Need To Know

Nearly 80% of people who are diagnosed with breast cancer will experience weight gain,1 reported to range between two pounds and 18 pounds. Not only is this an alarming trend for general health and self-image, but also some evidence suggests that pre-menopausal women who gain weight have a 1.5 fold increase risk of cancer recurrence.2 Other studies have shown that some types of treatment, such as anastrozole (Arimidex®), are less effective at treating breast cancer in patients who are obese.3

Stephanie Graff, MD, Director of the Breast Cancer Program at Sarah Cannon Cancer Institute at HCA Midwest Health and Associate Director of the Breast Cancer Research Program at Sarah Cannon Research Institute shares what people should know about the risk factors for weight gain after a breast cancer diagnosis.

Simultaneously hitting menopause

Women who become post-menopausal within the year they are diagnosed with breast cancer are the most likely to gain weight. An average woman without breast cancer gains three pounds with menopause.4 The risk of weight gain with menopause is highest in women who were at a healthy weight when reaching menopause. There does not seem to be a significant weight gain in women who quit hormone replacement at the time of a breast cancer diagnosis.

Treatment effects

Research has shown that nearly two-thirds of women who receive chemotherapy gain weight.1,5 Many patients are surprised to learn this—carrying their own mental stereotype of a bone-thin cancer patient. The weight gain for breast cancer chemotherapy regimens are dependent on a several variables including length of treatment and total steroid use. Steroids are necessary with many chemotherapy regimens to decrease risk of allergic reaction or to minimize nausea and other side effects. More and more, we are moving to “steroid low” approaches. However, on average the weight gain while on chemotherapy is five to six pounds; whereas little to no increase in weight has been seen in patients treated with surgery alone or tamoxifen.

In addition to the direct effects of the chemotherapy and associated medications on weight gain, in one study, up to 66% of patients reported that they ate to minimize symptoms of nausea, another way chemotherapy may lead to weight gain.6

Interestingly, many patients attribute weight gain after breast cancer to endocrine therapy, medicines like tamoxifen or anastrozole. Yet in the original research that compared tamoxifen to placebo both for the treatment of breast cancer (NSABP-B14 trial7) and the prevention of breast cancer (NSABP P1 trial8), there was weight gain between the tamoxifen treated group and the placebo treated group. This was later confirmed in the WHEL study.9 Certainly conflicting reports exist, which speaks to the reality that weight gain is a common struggle.

Emotional wellness & coping skills

Studying weight gain as it relates to our emotional wellness is difficult. But we can all certainly acknowledge the concept of “comfort food,” and that many people turn to food in times of stress, anxiety, boredom or discomfort. Sugar in particular is associated with a significant reaction in the brain similar to the most addictive drugs mediated by dopamine—the chemical in our brain most associated with happiness. In prior research, weight gain has been associated with an “inability to express emotion and with repressive coping styles.”10

Decreased physical activity

96% of patients treated for breast cancer report fatigue. Shifts in energy expenditures vary but exist across all treatments including surgery, chemotherapy, and radiation.10 Even small shifts in household tasks like housekeeping or laundry may have a net effect on a patient’s energy expenditure, and subsequently weight and body composition, while they are on treatment.

In light of the data, there is much that can be done to combat weight gain during and after a breast cancer diagnosis. Talk to your physician about support available to you including physical therapy and/or cancer exercise therapy, nutrition consultations, and psychosocial support in terms of counseling or support groups. Monitor your lifestyle for opportunities to be active, increase healthy choices around food, and reflect on your emotional wellness during and after your cancer diagnosis. Ask your physician to optimize use of supportive care medications, including steroids, nausea medications, and anti-depressants to help you maintain or lose weight during breast cancer treatment.


  1. Goodwin PJ, Ennis M, Pritchard KI et al. Adjuvant treatment and onset of menopause predict weight gain after breast cancer diagnosis. J Clin Onc 17:120-129
  2. Camoriano JK, Loprinzi CL, Ingle JN, et al: Weight change in women treated with adjuvant therapy or observed following mastectomy for node-positive breast cancer. J Clin Oncol 8:1327-1334, 1990
  3. Ligibel JA and Winer EP. Aromatase inhibition in obese women: How much is enough? J Clin Oncol 2012 Aug 20; 30:2940.
  4. Wing RR, Matthews KA, Kuller LH, et al: Weight gain at the time of menopause. Arch Intern Med 151:97-102, 1991
  5. Basaran G, Turhal NS, Cabuk D, et al. Weight gain afteradjuvant chemotherapy in patients with early breast cancer in Istanbul Turkey. Med Oncol 2011; 28: 409-415
  6. Mukhopadhyay MG, Larkin S: Weight gain in cancer patients on chemotherapy. Proc Am Soc Clin Oncol 5:254, 1986 (abstr 992)
  7. Dignam JJ, Wieand K, Johnson KA, Fisher B, Xu L, Mamounas EP. Obesity, Tamoxifen Use, and Outcomes in Women With Estrogen Receptor–Positive Early-Stage Breast Cancer. Journal of the National Cancer Institute. 2003;95(19):1467-1476
  8. Fisher B, Costantino JP, Wickerham DL, et al. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study. J Natl Cancer Inst 1998; 90: 1371-1388
  9. Saquib N, Flatt SW, Natarajan L, et al. Weight gain and recovery of pre-cancer weight after breast cancer treatments: evidence from the women’s healthy eating and living (WHEL) study. Breast Cancer Res Treat 2007; 105: 177-186
  10. Levine EG, Raczynski JM, Carpenter JT: Weight gain with breast cancer adjuvant treatment. Cancer 67:1954-1959, 1991
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