Candesartan and carvedilol for primary prevention of subclinical cardiotoxicity in breast cancer patients without a cardiovascular risk treated with doxorubicin

Background: There is no proven primary preventive strategy for doxorubicin-induced subclinical cardiotoxicity (DISC), especially among patients without a cardiovascular (CV) risk. We investigated the primary preventive effect on DISC of the concomitant use of angiotensin receptor blockers (ARBs) or beta-blockers (BBs), especially among breast cancer patients without a CV risk. Methods: A total of 385 patients who were scheduled for doxorubicin chemotherapy were screened. Among them, 195 patients of the study populations were included and were randomly divided into two groups [candesartan 4 mg q.d. vs. carvedilol 3.125 mg q.d.] and patients who were unwilling to take one of the medications were evaluated as controls. The primary outcomes were the incidence of early DISC (DISC developing within 6 months after chemotherapy), and late DISC (DISC developing only at least 12 months after chemotherapy). Result: Compared with the control group (8 out of 43 patients (18.6%)), only the candesartan group (4 out of 82 patients (4.9%)) showed a significantly lower incidence of early DISC (p = 0.022). Compared with the control group, the candesartan group demonstrated a significantly reduced decrease in left ventricular ejection fraction (LVEF) throughout the study period [−1.0% vs. −3.00 (p < 0.001) at the first follow-up, −1.10% vs. −3.40(p = 0.009) at the second follow-up]. Conclusions: Among breast cancer patients without a CV risk treated with doxorubicin-containing chemotherapy, subclinical cardiotoxicity is prevalent and concomitant administration of low-dose candesartan might be effective to prevent an early decrease in LVEF. Further large-scale, randomized controlled trials will be needed to confirm our findings.