Use of trastuzumab as adjuvant therapy for HER2-positive early breast cancer
This clinical practice guideline is based on available evidence from six randomised trials (five adjuvant and one neoadjuvant) assessing the use of trastuzumab in the treatment of HER2-positive early breast cancer:
- four trials randomised patients to adjuvant trastuzumab with chemotherapy (BCIRG 006;4 FinHer;5 NCCTG-N98316;6 NSABP-B316)
- one trial randomised patients to adjuvant trastuzumab after chemotherapy (HERA7,8)
- one trial randomised patients to neoadjuvant trastuzumab with chemotherapy (Buzdar9).
Data from two trials (NCCTG-N9831 and NSABP-B31) were reported in a combined data analysis. Five randomised trials of adjuvant trastuzumab showed an improvement in disease-free survival and three showed improvements in overall survival in women with HER2-positive early breast cancer. One trial of neoadjuvant trastuzumab showed an improvement in pathologic complete response (pCR) rate. See Summary of Results.
The scheduling of trastuzumab (weekly or 3-weekly) did not appear to affect treatment outcome, although a direct comparison of the two regimens has not been reported. While an overall survival benefit has been demonstrated using trastuzumab for 1 year, either sequentially or concurrently with chemotherapy, the optimal duration and sequence of administration of trastuzumab is unknown.
All four adjuvant trials reported a decline in cardiac function associated with trastuzumab (both symptomatic and asymptomatic). The risk of congestive heart failure was reduced when trastuzumab was given with non-anthracycline-based chemotherapy. The long-term side effects of trastuzumab are not yet known.
Use of trastuzumab for HER2-positive metastatic breast cancer
This clinical practice guideline is based on available evidence from six randomised trials assessing the use of trastuzumab in the treatment of HER2-positive metastatic breast cancer:
- three trials compared chemotherapy alone with chemotherapy plus trastuzumab(Gasparini;10 M77001;11 Slamon12)
- two trials compared trastuzumab-containing regimens (BCIRG 007;13 Vogel14,15)
- one trial started randomising HER2-positive and negative patients to chemotherapy with or without trastuzumab but ceased randomisation in HER2-positive patients after publication of other trial data (CALGB 984016)
Two of the trials that compared chemotherapy alone with chemotherapy plus trastuzumab showed an improvement in progression-free survival and an improvement in overall survival in women with HER2-positive metastatic breast cancer. See Summary of Results.
No trials have reported direct comparisons of different trastuzumab regimens. The trials that demonstrated a benefit of trastuzumab with chemotherapy used a weekly dose of trastuzumab.
No trials have evaluated the optimal duration of treatment; trastuzumab was used until disease progression or unacceptable toxicity. Two trials reported a decline in cardiac function associated with trastuzumab (in combination with an anthracycline and cyclophosphamaide or with docetaxel).