Weight change associated with anastrozole and tamoxifen treatment in postmenopausal women with or at high risk of developing breast cancer

Abstract

Weight gain is commonly reported by breast cancer patients on tamoxifen or aromatase inhibitors. Since weight gain may impact on outcome and compliance we have prospectively assessed the effects of these agents on weight change in three randomised trials for the treatment or prevention of breast cancer. Data on weight change in postmenopausal women from three large clinical trials investigating endocrine therapy for the treatment or prevention of breast cancer were analysed (ATAC, IBIS-I and IBIS-II). In the IBIS-I study, mean weight change on tamoxifen was +0.1 kg (SD 0.1) compared with +0.3 kg (SD 0.1) in women taking the placebo (P = 0.3) between baseline and 12 months of follow-up. In the IBIS-II trial, no statistically significant difference was found between anastrozole and placebo after 12 months of follow-up [+0.8 kg (SD 5.3) vs. +0.5 kg (SD 7.4), P = 0.5]. In the ATAC trial, no statistically significant differences in weight gain between anastrozole and tamoxifen were found after 12 months of follow-up [+1.4 kg (SD 3.9) vs. +1.5 kg (SD 4.0), P = 0.4]. Significant baseline predictors for gaining more than 5 kg of weight after 12 months of follow-up were: being younger than 60 years old, smoking and mastectomy. All three trials demonstrate that weight gain occurs primarily within the first 12 months of active treatment in a subset of patients. In the prevention trials, weight gain does not differ between anastrozole, tamoxifen and placebo and also did not differ between anastrozole and tamoxifen in the treatment trial.

Weight gain during adjuvant endocrine treatment for early-stage breast cancer: What is the evidence?

“…Table 1 presents an overview of findings from the seven remaining randomized controlled efficacy trials. Time frames range from 1 to 5 years on ET, with most results presented as the proportion of women reporting weight gain in general or as a ''bothersome'' symptom; in only one study, the amount of weight change (kilograms) was published [32]. Most studies reported no significant difference in weight or weight change between ET and placebo or between tamoxifen and AI.…”

“…In studies providing the proportion of women on tamoxifen who reported weight gain, the percentages were 41 % at Year One [32], 48 % at Year Two [33], and from 38 to 55 % at Year Five [34,35]. One study of women on tamoxifen for 5 years observed that reports of weight gain decreased with advancing age: 43 % among women under age 49 years, 39 % aged 50-59 years, and 33 % aged 60 years or older [34].…”

“…One study of women on tamoxifen for 5 years observed that reports of weight gain decreased with advancing age: 43 % among women under age 49 years, 39 % aged 50-59 years, and 33 % aged 60 years or older [34]. In studies providing the proportion of women on a specific AI who reported weight gain, the percentages were 39.5 % on anastrozole at Year One [32], 47 % on exemestane at Year Two [33], 21 % on letrozole at Year Three [36], and 7-51 % on exemestane at Year Five [35,37].…”

Body weight changes in breast cancer patients following adjuvant chemotherapy and contributing factors

“…Since weight gain may affect the outcome and compliance of breast cancer patients (21,22), we should assess the effects of multiple factors on weight gain for the prevention of breast cancer. There are several factors contributing to weight gain following adjuvant chemotherapy, such as age and weight at diagnosis, menopausal status, chemotherapeutic regimen, receptor status, clinical stage and number of chemotherapy cycles.…”

Adverse effects of adjuvant endocrine therapy

“…Около 36-50% пациен-ток набирают вес как в ходе всего периода адъювантного лечения, так и в отдаленные сроки после него [25]. Большинство исследований, сравнивающих ГТ Тамоксифеном с плацебо или ИА, не выявило статистиче-ских различий в изменении веса между группами, в то время как химиотерапия значимо ассоциировалась с набором веса [25][26][27]. Таким образом, миф, что именно тамоксифен вызывает увеличение массы тела, не под-тверждается данными исследований.…”