Risk factors for anthracycline-associated cardiotoxicity

Carbonyl reductase (CBR) catalyzes anthracycline metabolism, and single nucleotide polymorphisms (SNPs) in CBR impact metabolic efficiency. In pediatric patients, homozygosity for the major allele (G) in the CBR3 gene was associated with increased risk of anthracycline cardiotoxicity. We hypothesized that CBR SNPs contribute to cardiotoxicity in adults.

We retrospectively identified female breast cancer patients in the Columbus Breast Tissue Bank Registry treated with adriamycin and cytoxan (AC) from 2003 to 2012. We selected patients who developed cardiomyopathy, defined as a drop in ejection fraction to <50 % or >15 % decrease from pre-therapy. Univariate and multivariate logistic regressions were performed to identify cardiotoxicity risk factors. SNPs were genotyped, and frequency of the major allele (G)/minor allele (A) of the CBR3 and CBR1 genes was calculated.

We identified 52 cases of cardiotoxicity after AC and 110 controls. Multivariate analysis showed that trastuzumab (p = 0.009), diabetes (p = 0.05), and consumption of >8 alcoholic drinks/week (p = 0.024) were associated with higher cardiotoxicity risk. Moderate alcohol consumption (<8 drinks/week) was associated with lower risk (p = 0.009). No association was identified between CBR SNPs and cardiotoxicity (CBR1 p = 0.261; CBR3 p = 0.556).

This is the first study to evaluate SNPs in the CBR pathway as predictors of AC cardiotoxicity in adults. We did not observe any significant correlation between cardiotoxicity and SNPs within the CBR pathway. Further investigation into CBR SNPs in a larger adult sample is needed. Additional exploration into genomic predictors of anthracycline cardiotoxicity may allow for the development of preventative and therapeutic strategies for those at risk.