The potential for doxorubicin-induced cardiac toxic effects should be considered in the selection of chemotherapeutic regimens for an individual patient. Recognized risk factors for cardiac toxicity include advanced age, prior chest-wall radiation therapy, prior anthracycline exposure, hypertension, diabetes, and known underlying heart disease. The cardioprotective drug, dexrazoxane, has been shown to decrease the risk of doxorubicin-induced cardiac toxicity in patients in controlled studies. The use of this agent has permitted patients to receive greater cumulative doses of doxorubicin and allowed patients with cardiac risk factors to receive doxorubicin.[98,99,100,101] Dexrazoxane has a similar protective effect in patients receiving epirubicin. The risks of cardiac toxicity may also be reduced by administering doxorubicin as a continuous intravenous infusion.
Studies comparing high-dose chemotherapy with stem cell support to conventional chemotherapy in patients with metastatic disease indicate no OS or relapse-free survival benefit for patients receiving high-dose chemotherapy with stem cell support.[104,105][Level of evidence: 1iiA] In the absence of data suggesting a benefit from high-dose chemotherapy with stem cell support, this remains an area of clinical evaluation.[106,107]
Bevacizumab is a humanized monoclonal antibody directed against all isoforms of vascular endothelial growth factor-A. Its role in the treatment of metastatic breast cancer remains controversial. The efficacy and safety of bevacizumab as a second- and third-line treatment for patients with metastatic breast cancer were studied in a single, open-label, randomized trial. The study enrolled 462 patients who had received prior anthracycline and taxane therapy and were randomly assigned to receive capecitabine with or without bevacizumab. The study failed to demonstrate a statistically significant effect on PFS (4.86 months vs. 4.17 months; HR, 0.98) or OS (15.1 months vs. 14.5 months).[Level of Evidence: 1iiA]
ECOG-2100 (NCT00028990), a completed, open-label, randomized, phase III trial, demonstrated that the addition of bevacizumab to paclitaxel significantly prolonged median PFS compared with paclitaxel alone as the initial treatment for patients with metastatic breast cancer (11.8 months vs. 5.9 months; HR, 0.60; P <.001).[Level of Evidence: 1iiA] However, the addition of bevacizumab did not improve OS (26.7 months vs. 25.2 months, P = .16). Notably, patients treated on the bevacizumab-containing arm had significantly higher rates of severe hypertension, proteinuria, cerebrovascular ischemia, and infection.