Progress made in early cancer diagnosis and therapy has translated into increased longevity for patients with breast cancer. As survival has increased, the potential cardiotoxicity of cancer chemotherapy regimens has become an important issue for survivorship. Doxorubicin-induced cardiotoxicity has been demonstrated at a cumulative dose of ≤ 300mg/m2, with histopathological changes seen in endomyocardial biopsy tissue from patients receiving as little as 240mg/m2 of doxorubicin. Individual risk stratification and early detection of chemotherapy-induced cardiotoxicity are crucial to prevent irreversible cardiac dysfunction. There is accumulating evidence for the utility of echocardiographic indices such as left ventricular global longitudinal strain (GLS) in the detection of early chemotherapy induced cardiac injury. We have previously highlighted a predictive role of genetic polymorphisms in the carbonyl reductase 3 gene CBR3 in anthracycline-related cardiomyopathy following childhood cancer. Consistent with our prior work, we hypothesized that breast cancer patients homozygous for the CBR3 V244M G allele would exhibit worsening GLS following DOX treatment when compared with patients homozygous for the A allele. We recruited 138 patients with breast cancer receiving treatment with DOX (total cumulative dose: 240mg/m2). 72 patients received an echocardiogram analyzing global longitudinal strain by speckle tracking at baseline (t0 month) and at 6 months (t6 months) of follow up after DOX treatment. Patients were genotyped for variants associated with anthracycline-related toxicity. In agreement with our previous findings and hypothesis, our interim analysis suggested that patients homozygous for the CBR3 V244M G allele (CBR V244) exhibited GL changes at 6 months after DOX therapy suggestive of cardiotoxicity in comparison to individuals homozygous for the A allele (CBR3 M244) (-1.2 ±3.5 vs 1±1.6; mean±SEM, p=0.8 by Mann-Whitney test). Although the differences between CBR3 genotype groups are not significant at p<0.05, the direction and magnitude of changes in ventricular GL are well in line with various reports describing early detection of cardiotoxicity in similarly treated breast cancer patients. This study outlines a potential role for screening CBR3 polymorphisms in patients prior to DOX therapy and highlights a need for further investigation into the pharmacogenomics of chemotherapy-induced cardiotoxicity.

Citation Format: Lang JK, Quinones AL, Hageman Blair R, Early AP, Levine EG, Opyrchal M, Blanco JG, O'Connor T. Association of CBR3 polymorphisms with an early change in cardiac function as assessed by left ventricular global longitudinal strain in breast cancer patients treated with doxorubicin [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-08.