P5-18-12: Perception, Practice and Toxicity of Adjuvant Treatment of HER2+ Breast Cancer in Wisconsin.
Authors: Rocque GB , Onitilo AA , Engel JM , Pettke EN , Boshoven AM , Zhang S , Kim KM , Rishi S , Waack B , Wisinski KB , Tevaarwerk AJ , Burkard ME 
Published: June 2012

INTRODUCTION: Multiple trastuzumab-containing (neo)adjuvant regimens are used for HER2+ BrCa, but the experience with these regimens in routine practice is not reported. Some oncologists select TCH based on BCIRG 006, whereas others prefer anthracycline-based therapy. We evaluated whether oncologists’ perceptions of these regimens match clinical experience.

METHODS: We surveyed 151 Wisconsin (WI) oncologists regarding factors impacting selection of TCH versus AC-TH; 65 (42%) responded. At the same time, we reviewed 200 cases of HER2+ BrCa treated with adjuvant trastuzumab from 2003 to 2010 at the University of Wisconsin Carbone Cancer Center (UW) and the Marshfield Clinic. We collected baseline patient and tumor characteristics, regimen administered, and toxicities as assessed by lab values, cardiac ejection fraction (EF), hospitalizations, dose reductions/delays, and ability to complete therapy.

RESULTS: Two-thirds of surveyed oncologists prefer anthracycline-based therapy over TCH. Of oncologists preferring TCH, 20 of 23 had been in practice for &gt;10 years. Oncologists perceived that AC-TH and TCH were equally likely to be completed. The majority of physicians select therapy based on patient age and stage, with a preference for AC-TH for node-positive disease and TCH for early stage (T1a-bN0) tumors. Despite BCIRG 006 remaining unpublished at the time of the survey, peer-review publication was cited as the most important factor in selecting this regimen. Although use of granulocyte colony stimulating factor (GCSF) in BCIRG 006 has not reported, 50% of oncologists indicated routine use with cycle 1 of TCH. Of the 200 cases reviewed, 114 women received AC-TH, 48 women received TCH, and 38 had other regimens. The median age was 53 years old, 52% had node positive disease. Acute toxicity trended higher with TCH. For example, there were fewer dose modifications/delays for AC-TH than TCH (31% vs. 46%, p=0.07). This may have been due to common use of GCSF with AC-TH (77% vs. 33% use with TCH). Neutropenic fever (NF) was higher with TCH, reaching 25% incidence when administered without GCSF. However, NF did not occur in the 8 TCH patients who received cycle 1 GCSF. There was no correlation between NF and patient age. The incidence of left ventricular EF decline leading to cessation of trastuzumab was similar for both regimens (19.4% AC-TH vs. 14.6% TCH; p = 0.64). Trastuzumab was completed as planned in 70% of patients. Although EF decline was most common explanation, 13% of early trastuzumab discontinuations occurred for other reasons.

CONCLUSION: TCH and AC-TH are the most commonly administered adjuvant regimens for WI women with HER2+ BrCa. Amongst WI oncologists, TCH is perceived as safer, but is less likely to be recommended for node-positive BrCa. This retrospective analysis suggests that acute myelosuppression is greater for TCH, with a significant rate of NF. Per ASCO guidelines, these data suggest GCSF should be used routinely with TCH due to high rate of FN. We were intrigued that oncologists who have been in practice longer are more likely to choose TCH. The reasons for this are unclear, but are perhaps related to prior experience with long-term cardiotoxicity with AC-TH.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-18-12.