Disease-free and overall survival significantly improved among women with HER2-positive breast cancer when 1 year of adjuvant trastuzumab was added to their treatment regimen.
In a recent study, 3,222 women with HER2-positive early-stage breast cancer were randomly assigned to one of three treatment regimens:
- The anthracycline doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan) followed by docetaxel (Taxotere) every 3 weeks (a standard regimen, referred to in the study as AC-T)
- AC-T plus trastuzumab (Herceptin)
- Docetaxel and carboplatin plus 52 weeks of trastuzumab (a regimen referred to as TCH).
The estimated disease-free survival (DFS) and overall survival (OS) rates at 5 years were 75% (DFS) and 87% (OS) in the AC-T group; 84% (DFS) and 92% (OS) among the women receiving AC-T plus trastuzumab; and 81% (DFS) and 91% (OS) for the TCH recipients.
Both trastuzumab regimens were found to be more efficacious than AC-T, but did not differ significantly in efficacy from one another. However, the group receiving AC-T plus trastuzumab registered the highest rates of heart failure, and cardiac dysfunction was significantly higher among those patients than among those following the TCH regimen. Of the eight cases of leukemia reported, seven occurred in the groups receiving the anthracycline-based regimens and one in a patient in the TCH group subsequent to receiving an anthracycline outside the study.
The investigators concluded that the risk-benefit ratio favored the nonanthracycline TCH regimen over AC-T plus trastuzumab based on its similar efficacy, fewer acute toxic effects, and lower risks of cardiotoxicity and leukemia (N Engl J Med. 2011;365:1273-1283).