March 02, 2020
Significant weight gain after a diagnosis of breast cancer may be a bigger problem than previously thought, and clinicians need to do more to help patients manage it, say the authors of a national survey conducted in Australia.
"We found that two-thirds of our respondents were currently overweight or obese," report Carolyn Ee, MBBS, PhD, of the NICM Health Research Institute, Western Sydney University, Penrith, New South Wales, and colleagues.
"Because weight gain after breast cancer may lead to poorer outcomes, efforts to prevent and manage weight gain must be prioritized and accelerated particularly in the first year after diagnosis," they comment.
Their article was published online February 20 in BMC Cancer.
The 60-item anonymous online survey was sent to 1835 members of the Breast Cancer Network Australia Review and Survey Group.
Although the response rate for the online survey was only 15%, most women reported a "high" level of concern about weight gain — and with good reason. The results showed that 64% of women gained an average of 9 kg (20 lb), and 17% gained >20 kg (44 lb).
Overweight and obesity are strongly implicated in the development of breast cancer, the authors note. Weight gain after diagnosis is associated with morbidity and all-cause mortality and may increase the risk for breast cancer recurrence by 30% to 40%.
The survey, which also collected data from 26 women who were participants in online women's health and breast cancer support groups, did not include information on quality of life and levels of distress. "Additional research in this area appears to be warranted," the study authors suggest.
In a press statement, Ee noted that 77% of women reported that weight gain had occurred in the 12- to 18-month period after diagnosis. This could provide a "window of opportunity" for intervention, she said.
"Timing may be the key in helping women to manage weight after a diagnosis of breast cancer," she added. "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."
Coauthor John Boyages, MBBS, PhD, a radiation oncologist at the Icon Cancer Center, Sydney Adventist Hospital, Wahroonga, emphasized that all women should be prescribed exercise after being diagnosed with breast cancer. "Prescribing a healthy lifestyle is just as important as prescribing tablets," he said.
"As doctors, we really need to actively think about weight, nutrition, and exercise and advise about possible interventions. [Among patients with breast cancer,] weight gain adds to self-esteem problems, increases the risk of heart disease and other cancers, and several reports suggest it may affect prognosis and also increases the risk of lymphedema," he added.
"More effort needs to be geared to treating the whole body, as we know obesity is a risk factor for poorer outcomes when dealing with breast cancer," commented Stephanie Bernik, MD, chief of breast service at Mount Sinai West and associate professor of surgery at the Icahn School of Medicine at Mount Sinai in New York City. She was not involved in the study and was approached for comment.
Berwick also agreed that meeting with a nutritionist or receiving weight loss support is helpful for patients with cancer, but she added that not all cancer centers have the resources to provide these services.
Of 309 women who responded to the survey, complete data for pre- and post-diagnosis body mass index (BMI) were collected from 277 respondents, representing 15% of those surveyed.
Of these women, 254 had been diagnosed with stage I–III breast cancer; 33 had been diagnosed with ductal carcinoma in situ. The mean age of the patients was 59 years.
The results showed that for 20% of women, BMI increased from a healthy weight range at the time of diagnosis (BMI <25) to an unhealthy weight range (BMI >25). In addition, for 4.8% of patients, BMI increased from an overweight range (BMI 25 to <30) to obesity (BMI >30), and 60.7% reported an increase in BMI >1 kg/m2. Conversely, only a small proportion of women lost weight ? 6% experienced a decrease of more than one BMI category.
Weight gain occurred within the first 2 years of diagnosis in 87% of women and within the first 12 months in 58%. In women who gained >10 kg (22 lb), 78% said they were highly concerned about it, as did 59% of women who gained >5 kg (11 lb).
Among all age groups (35 to 74 years), 69% experienced excess weight gain that was 0.48 kg higher each year compared with age-matched control persons who had not been diagnosed with breast cancer. Over 5 years, this represented an additional weight gain of 2 kg (5 lb) among women with breast cancer.
When approached for comment, Bernick agreed with the authors that these results should be interpreted with caution.
She pointed to the self-reporting bias and the fact that only 15% of women responded to the survey. "Perhaps it was only women who had gained weight who found it worthwhile reporting their experience with weight gain after a breast cancer diagnosis," she suggested.
Even so, there are many reasons why weight gain during treatment for breast cancer presents a problem for women in the United States as well as Australia, Bernik told Medscape Medical News.
"Women undergoing chemotherapy may not have the energy to keep up with exercise regimens and may find eating food comforting," she pointed out. "Because chemotherapy delivery and the after effects may take up a few days out of every 2 to 3 weeks, women have less time and energy to eat correctly or exercise. Furthermore, women sometimes get steroids while receiving chemotherapy, and this is known to drive up one's appetite."
The authors have disclosed no relevant financial relationships.