BOSTON — Nearly one in five breast cancer survivors will gain more than 10% of their body weight in the 6 years following their diagnosis, according to new research presented at ENDO 2024, the annual meeting of the Endocrine Society.
Younger age and lower weight at diagnosis were the strongest predictors of this excessive weight gain over time.
“Weight gain is a common concern after breast cancer diagnosis and treatment,” said Maria Daniela Hurtado Andrade, MD, PhD, of the Mayo Clinic in Jacksonville, Florida, who led the research. “This weight gain in breast cancer survivor increases breast cancer recurrence and mortality, increases cardiovascular disease and mortality, and also increases all-cause mortality.”
Previous studies have found an association between breast cancer survivorship and weight gain, but the reported incidences of weight gain — and the amounts gained — have been highly variable, she added.
In the study, researchers used the Mayo Clinic Breast Cancer Registry to identify 4575 breast cancer survivors and tracked their weight over the course of 6 years following cancer diagnosis. These patients were age-matched to women in the general population selected from the Rochester Epidemiology Project, which contains the medical records of residents of 27 counties in Minnesota and Wisconsin. All controls had no history of cancer or bariatric surgery.
Nearly all patients and controls were White (97%); at breast cancer diagnosis, patients were on average 58 years of age and weighed 76 kg (165.5 lb). Controls had similar ages and baseline weights.
At 6 years following breast cancer diagnosis, average weight gain was modest: Breast cancer survivors gained 1.6% of their body weight, compared with 0.7% in controls (P = .004).
However, 18% of breast cancer survivors had gained at least 10% of their body weight over that time. By comparison, 8% of controls experienced this excessive weight gain during that same time frame (P < .0001). The same trend was observed for 15% and 20% weight gain.
After adjustment for confounding factors, younger age at breast cancer diagnosis and lower baseline weight were the strongest predictors of more than 10% weight gain. BRCA2 mutation and use of systemic chemotherapy treatment were also associated with excessive weight gain.
Several factors could be driving weight gain in these patients, said Zeynep Madak-Erdogan, PhD, at the University of Illinois Urbana-Champaign, who was not involved with the research. Her work focuses on how diet and nutrition affect hormone action in postmenopausal women and breast cancer survivors. Certain therapies can induce temporary or permanent menopause in patients, “and this early menopause might shift balance of estrogens and cause increased weight gain,” she said. Along the same lines, endocrine therapies can also affect estrogen production.
Stress and exhaustion from treatment — especially compounded by the two previous factors — are also likely culprits in weight gain, she continued.
“These findings highlight importance of lifestyle interventions,” added Dr. Madak-Erdogan. “In addition to changes in the diet (increased vegetable, fruit, [and] whole grain intake; reduction in saturated fats, alcohol, [and] sweetened beverage consumption), survivors should be consulted on importance of regular exercise.”
“These data clearly show we must consider weight changes in breast cancer survivors, and we must find ways of instituting strategies to mitigate these weight gains,” Dr. Hurtado Andrade said. “These women have a lot to think of when they have a breast cancer diagnosis, so we also must find ways of instituting these measures in a way that doesn’t increase the burden of their health.”
Dr. Hurtado Andrade has received research funding from the National Institutes of Health and by Phenomix Sciences. She also is a consultant for Novo Nordisk. These three organizations were not involved with this study. Dr. Madak-Erdogan had no disclosures.
A version of this article first appeared on Medscape.com.