Gaining weight after being diagnosed with breast cancer may be a bigger problem than previously thought, and doctors need to do more to help women manage this weight gain, according to a study done in Australia.
The research was published on Feb. 20, 2020, by the journal BMC Cancer. Read “Weight before and after a diagnosis of breast cancer or ductal carcinoma in situ: a national Australian survey.”
Excess weight and breast cancer
Overweight and obese women — defined as having a BMI (body mass index) higher than 25 — have a higher risk of being diagnosed with breast cancer compared to women who maintain a healthy weight, especially after menopause. Being overweight also can increase the risk of breast cancer coming back (recurrence) in women who’ve been diagnosed with the disease.
This higher risk is partially because fat cells make estrogen; extra fat cells mean more estrogen in the body, and estrogen can make hormone-receptor-positive breast cancers develop and grow. Scientists also have recently found that extra fat cells can trigger long-term, low-grade inflammation in the body. Chronic inflammation has been linked to a higher risk of breast cancer recurrence; the proteins secreted by the immune system seem to stimulate breast cancer cells to grow, especially estrogen-receptor-positive breast cancer in postmenopausal women.
We also know that women who gain weight after being diagnosed with breast cancer are more likely to have worse outcomes and also more likely to die from any cause.
Researchers did this study to understand how many women in Australia were overweight or obese after being diagnosed with breast cancer, and also to look at the pattern of weight gain after diagnosis.
How the study was done
To do the study, researchers analyzed survey results from 309 women living in Australia who had been diagnosed with breast cancer. The survey was done online between November 2017 and January 2018. The characteristics of the women who completed the survey:
- 92.5% were white
- the average age was 59.1 years; ages ranged from 33 to 78
- the average age at diagnosis was 50.9 years
- 43% were premenopausal and 12% were perimenopausal when diagnosed
- 10.7% were diagnosed with ductal carcinoma in situ (DCIS)
- 82% were diagnosed with stage I to stage III breast cancer
- the average time since diagnosis was 8.2 years
- 18.8% were treated with tamoxifen alone
- 47.3% were treated with other hormonal therapy medicines
- 40.5% were taking hormonal therapy medicine when they completed the survey
Weight changes after a breast cancer diagnosis
The survey found that nearly two-thirds — 63.7% — of the women reported an average weight gain of about 20 pounds after being diagnosed with breast cancer. Overall, 17% of the women reported gaining more than 44 pounds.
The women’s average weight when they were diagnosed was about 157 pounds. When they completed the survey, the women’s average weight was about 167 pounds.
Just under half the women were overweight or obese when they were diagnosed, but by the time they completed the survey, 67.3% of the women were overweight or obese. The number of women who were obese increased the most: 17% of the women were obese when diagnosed, and 31.9% of the women were obese when they completed the survey.
Almost 75% of the women who were obese when they completed the survey said they had high levels of concern about their weight.
Most of the women — 77% — said they gained weight within the first 12 to 18 months after being diagnosed with breast cancer.
“This could be the ideal window of opportunity to provide additional support for weight management among women [diagnosed] with breast cancer,” said Carolyn Ee, senior research fellow at Western Sydney University and lead author of the paper. “As well as significant weight gain, we also found high levels of concern about weight among our survey participants,” she continued. “Timing may be the key in helping women to manage weight after a diagnosis of breast cancer. Cancer services and general practitioners play an important role in having early conversations with women and referring them to a team of qualified healthcare professionals such as dieticians and exercise physiologists with experience in cancer.”
“As doctors we really need to actively think about weight, nutrition, and exercise and advise about possible interventions,” said co-author John Boyages, of the ICON Cancer Center at Sydney Adventist Hospital. “Prescribing a healthy lifestyle is just as important as prescribing tablets.”
What this means for you
As many of us know, trying to lose weight — especially as we get older — can be hard and frustrating.
Still, it can be done with careful changes to your diet and regular exercise. The first thing to do is to talk to your doctor about a healthy weight for you based on your age, height, body type, and activity level. Then ask your doctor about a safe and sensible plan to lose weight that is specifically designed for you and your needs.
Once you have the OK from your doctor and a weight goal, you can create a healthy eating plan that meets your nutritional needs. You may want to talk to a registered dietitian about how to create a healthy eating plan that’s tailored to your specific needs and likes.
Some women say that it helps to think of eating well and exercising as important parts of their treatment plans. Remember to be nice to yourself; don’t punish yourself.
In the Breastcancer.org Nutrition section, the Eating to Lose Weight After Treatment pages can help you assess your weight and create a healthy eating plan. And the Breastcancer.org Exercise pages can help you find a trainer and learn how to stick to an exercise routine.
Written by: Jamie DePolo, senior editor
Reviewed by: Brian Wojciechowski, M.D., medical advisor
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