Abstract P6-14-04: Is fat mass more effective than body mass index (BMI) to predict toxicity in early breast cancer patients treated with doxorubicin and cyclophosphamide?

Abstract

Abstract Patients and Methods:We performed a retrospective cohort study of 207 operated breast cancer women treated with doxorubicin (60 mg/m2) and cyclophosphamide (600 mg/m2) for adjuvant setting between 2007 and 2016. Patients' demographic features, toxicities, fat mass, body mass index (BMI) and body surface area (BSA) were evaluated in their charts. Patients were evaluated according to fat mass (high ≥35% vs. low <35%), BMI (obese ≥30 kg/m2 vs. nonobese <30 kg/m2), and BSA (≥1.73 vs. <1.73) levels. Results:Median age was 46 (23-82) and 61.8% of the patients (n=128) were premenopausal. Median fat mass, BSA, and BMI level was 37 (10-55), 1.75 (1.3-2.27) and 29.4 (16-54.7), respectively. Grade ≥3 toxicity was observed in 68 patients (%32.9). Although, in univariate analyses [table 1] there are no differences in terms of grade ≥3 toxicity according to BMI (in obese and nonobese patients, 34.8% vs. 31.4%, respectively, p=0.589), and BSA (in patients with m2 ≥1.73 vs. m2 <1.73, 35.8% vs. 29.6%, respectively, p=0.344), statistically significant difference was observed according to fat mass (fat mass high and low, 39.1% vs. 25.0%, respectively, p=0.031). In multivariate analyses [table 2], fat mass [<35 vs. >35, OR (odds ratio): 2.341 %95CI:0.39-5.27, p=0.040] was affect grade ≥3 toxicity, while BMI [<30 vs. >30; OR:0.876 %95 CI=0.392-1.959, p=0.748], BSA [<1,73 vs. >1.73 m2, OR:0.956, %95CI:0.450-2.034, p=0.908], age [<50 vs. >50, OR:2.171, %95CI:0.338-13.956, P= 0.414], menopausal status [premenopausal vs. postmenopausal, OR:4.374, %95CI:0.661-28.964, p=0,126], stage [1,2 vs 3, OR:0.535, %95CI:0.279-1.024, p=0.059] and histologic subtype [ductal vs. others; OR:2.010 %95 CI=0.368-2.010, p:0.729] was not. Grade ≥3 toxicity according to BMI, BSA, and fat massMethodGrade ≥3 toxicityP valueBMI (obese vs nonobese)34.8% vs. 31.4%0.589BSA (≥1.73 vs. m2 <1.73)35.8% vs. 29.6%0.344Fat mass (≥35% vs. <35%)39.1% vs. 25.0%0.031BMI: Body mass index, BSA: body surface area Multivariate analayses for grade ≥ 3 tocicityParametersOdds Ratio%95 Confidence IntervalP valueFat mass (≥35% vs. 35%)2.3410.39-5.270.040BMI (≥30 vs. < 30)0.8760.392-1.9590.748BSA (<1,73 vs. >1.73)0.9560.450-2.0340.908Age (≥50 vs. <50)2.1710.338-13.9560.414Menopausal status4.3740.661-28.9640,126Stage0.5350.279-1.0240.059Histhologic type2.0100.368-2.0100.729BMI: Body mass index, BSA: Body surface area Discussion:BSA-based dosing has been widely adopted in oncology as a means of safely administering cytotoxic drugs. In our study demonstrated that fat mass is most valuable than BSA and BMI for evaluation to grade ≥3 toxicity for breast cancer patients treated with AC in the adjuvant setting. Citation Format: Kaplan MA, Kavak H, Urakci Z, Nas N, Oruç Z, Yerlikaya H, Akdeniz N, Isikdogan A. Is fat mass more effective than body mass index (BMI) to predict toxicity in early breast cancer patients treated with doxorubicin and cyclophosphamide? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P6-14-04.