Abstract P1-12-16: Efficacy of adjuvant tamoxifen in hormone receptor-positive premenopausal breast cancer patients according to the body mass index

Abstract

Abstract Introduction: Obesity is an independent risk factor for the development of breast cancer and has been associated with poor breast cancer outcomes. But, this association usually depend on hormone-receptor positivity and ovarian activity. Obesity was confirmed as an adverse prognostic factor in patients treated with aromatase inhibitors, but the adverse effects in patients treated with tamoxifen was not known exactly. Thus, we aimed to examine the efficacy of adjuvant tamoxifen in hormone receptor-positive premenopausal breast cancer patients according to the body mass index (BMI). Material-Methods: Newly diagnosed hormone receptor-positive breast cancer patients who were premenopausal and non-metastatic were enrolled to the study. Patients with BMI ranging between 18.5 and 24.9 kg/m2 as normal weight patients (Arm A, n = 408), and patients with a BMI ranging ≥ 25 kg/m2 were overweight and obese patients (Arm B, n = 418). Results: The median follow-up time for this analysis was 36 (6-327) months. The median age was 39.5 (22-57) and 43 (20-56) in Arm A and Arm B, respectively (P<0.0001). The mean BMI was 22.1 ± 1.8 kg/m2 and 29.2 ± 3.3 kg/m2 of Arm A and Arm B, respectively ( P = <0.001). In both normal weight and overweight patients, the other baseline clinico-pathologic properties and the treatment history with radiotherapy and chemotherapy were similar and not statistically significant. In overweight and obese patients the history of diabetes mellitus and hypertension was significantly higher compared to normal weight patients. In patients with normal weight patients DFS rate was 88.5% and 78.2% whereas in overweight and obese patients DFS rate was 87.2% and 70.9% in the third and fifth years respectively (Figure 1) ( P = 0.43). In patients with normal weight patients OS rate was 98.5% and 93.2% whereas in overweight and obese patients OS rate was 94.6% and 87.4% in the third and fifth years respectively (Figure 2) ( P = 0.02). Conclusion: Our study showed that BMI have no worse effect on recurrence risk in patients treated with tamoxifen in hormone-receptor positive premenopausal breast cancer. Poor survival outcome was observed in overweight and obese patients can be due to dose limitations of chemotherapeutic agents and higher rate of comorbid diseases. Citation Format: Kadri Altundag, Mehmet AN Sendur, Sercan Aksoy, Taner Babacan, Yavuz Ozisik. Efficacy of adjuvant tamoxifen in hormone receptor-positive premenopausal breast cancer patients according to the body mass index [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-12-16.