Lower pretreatment body mass index (BMI) was identified as a risk factor for weight gain in women treated with adjuvant chemotherapy for breast cancer, a prospective study published in Breast has shown. 

Although results of studies of women treated for breast cancer have shown significant associations between adjuvant chemotherapy and weight gain, both pre- and postmenopausal women were included in those investigations. Furthermore, there was wide variability in the chemotherapy regimens administered to women in those studies. 

This study was a substudy of the multicenter Prospective Study of Outcomes in Sporadic versus Hereditary Breast Cancer (POSH) Study, which enrolled women ages 40 years and younger with early-onset breast cancer.  From May 2005 to January 2008, women entering POSH were also recruited for this substudy, which sought to evaluate changes in body weight. Multiple body measurements including height, weight, BMI, as well as measurements of the hips and waist were recorded following surgery but prior to administration of adjuvant therapy, and again at 12 months (±3 months) after diagnosis, by which time chemotherapy had been completed.

Of the 380 premenopausal patients identified for this analysis, hip and waist measurements were obtained from 257 of them at 12 months. Approximately three-quarters of the patients in this weight substudy received non-taxane-based chemotherapy regimens. 

Body weight gain of 5% or more occurred in 32% of the 12-month cohort. On multivariate analysis, only pretreatment BMI was a statistically significant predictor of subsequent weight gain (<.001). No associations were observed between weight gain and age at diagnosis; use of oral contraception; smoking history; family history of breast cancer; parity; ethnicity; type of chemotherapy or length of its administration; use of luteinizing hormone agonists, trastuzumab, or adjuvant radiotherapy; development of chemotherapy-induced amenorrhea; surgical oophorectomy; or ovarian irradiation. Although the overall cohort showed a weak association between antiestrogen use and weight gain, this was not observed in the 12-month cohort.

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“A considerable amount of the weight increase was not explained by the parameters in our analysis. Further research is required to examine other factors which may be influential on weight gain in breast cancer survivors,” concluded the study authors. 

ReferenceGandhi A, Copson E, Eccles E, et al. Predictors of weight gain in a cohort of premenopausal early breast cancer patients receiving chemotherapy.Breast. 2019;45:1-6.