Abstract P1-14-04: Cardiotoxicity of adjuvant trastuzumab chemotherapy in women with early-stage breast cancer under 50 years of age based on analysis of Japanese insurance claims data
Authors: Shimomura Akihiko , Ohtsu Hiroshi , Shimizu Chikako , Sase Kazuhiro 
Published: March 2022

Abstract
Background: Adjuvant chemotherapy with anti-HER2 therapy has markedly improved the postoperative life expectancy of women with HER2-positive breast cancer, but cardiotoxicity remains a challenge. Although East Asians, especially premenopausal women, have a lower incidence of cardiovascular disease attributable to traditional risk factors, it is unclear whether the same ethnic factors apply to cancer treatment-related cardiovascular disease. The purpose of this study is to detect rare but serious adverse events to provide real-world evidence for cardio-oncology. Materials and Methods: Women under 50 years of age who underwent their first surgery between January 2010 and December 2019 were extracted from JMDC, a national-level insurance claims database collected under Japan's universal health insurance system. Patients with a history of heart failure and those with less than six months records before surgery were excluded. Patients with both codes for diagnosis (breast cancer: C50) and surgery (K476) on the same receipt were defined as early breast cancer. Adjuvant chemotherapy was defined as anti-HER2, including trastuzumab (L01XC03), lapatinib (L01XE07), pertuzumab (L01XC13), or trastuzumab emtansine (L01XC14), prescribed within six months before or after surgery. Patients with a new episode of heart failure (Diagnosis: echocardiography 160072510, 160072610 or BNP 160162350, 160181250. Treatment: diuretics C03, beta-blockers C07, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers C09) were defined as cancer treatment-related cardiovascular disease (CTRCD). Results: Of the 11,594,000 subscribers in JMDC, 7,663 were eligible. The anti-HER2 group (n=863 (11%), median duration 13 months [IQR: 12-13]) was compared with the non-HER2 group ( n=6,800 (89%) ). Age 43 [39-46] vs 45 [41-47], anthracycline 602 (69.8%) vs 1,550 ( 22.8%), radiotherapy 496 (57.5%) vs 3,763 (55.3%), and tamoxifen 544 (63.0%) vs 4,809 (70.7%). Preoperative cardiovascular risk factors were diabetes 60 (0.9%) vs 7 (0.6%), hypertension 37 (4.2%) vs 157 (2.3%), dyslipidemia 17 (2.0%) vs 93 (1.4%). Preoperative echocardiography was 436 (50.5%) vs 1,282 (18.9%). CTRCD within 18 months postoperatively was 25 (2.9%) vs. 39 (0.6%), with an odds ratio of 5.2 [95% CI: 3.1-8.6]. Logistic regression analysis showed that the odds ratios for CTRCD were HER2: 3.0 [1.7-5.1], anthracycline: 3.4 [1.9-5.9], radiotherapy: 1.2 [0.7-2.0], tamoxifen: 1.4 [0.8-2.4], hypertension: 4.8 [2.3-10.2], :hyperlipidemia 1.5 [0.4-6.4], respectively. Conclusion: Real-world data indicate that premenopausal East Asians have a higher incidence of cardiac events with anti-HER2 therapy despite fewer cardiovascular risk factors. In addition, only about half of the patients underwent pretreatment cardiac function assessment as recommended in the guidelines.
Citation Format: Akihiko Shimomura, Hiroshi Ohtsu, Chikako Shimizu, Kazuhiro Sase. Cardiotoxicity of adjuvant trastuzumab chemotherapy in women with early-stage breast cancer under 50 years of age based on analysis of Japanese insurance claims data [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-14-04.