Testing procedures and reasons why HER2-positive breast cancer patients did not receive trastuzumab in the adjuvant setting.

Abstract

e11072 Background: Use of trastuzumab in the adjuvant and metastatic setting has been shown to improve outcomes (DFS and OS) in HER2+ patients. An earlier study found that 13% of HER2+ patients with stage II-III breast cancer did not receive trastuzumab. This study examined reasons HER2+ patients receiving adjuvant treatment did not get trastuzumab and examined HER2 testing patterns. Methods: Data and text fields of 12 community site EMRs were searched to identify patients believed to be HER2+ but with no record of trastuzumab treatment. Records from 1142 cases yielded 74 patients with invasive HER2+ disease but who were not treated with trastuzumab. For comparison, a random sample of 76 patients who did receive trastuzumab was identified. Chart extraction by experienced oncology nurses documented details of testing and reasons for non use of trastuzumab. Results: 95% of patients had documentation of IHC 3+ or FISH > 2.0. Treated patients were younger (53 vs. 66 yrs old), with later stage disease, larger tumor size, and a greater number of positive lymph nodes. The most common medical reasons for withholding trastuzumab were: small tumor size, negative nodes and early stage of disease (30%); advanced age (11%); and unspecified heart disease (5%). Patient reasons for declining trastuzumab included: declined systemic therapy or wanted hormonal treatment only (22%); perceived risk (11%); perceived lack of efficacy (8%); and cost (3%). There were no significant differences between patients who did or did not have documentation for non use (47%). Conclusions: In contrast to reports of inadequate HER2 testing based on administrative claims data, this detailed medical record review showed 95% correct testing. Oncologists treating patients for early-stage cancer appeared to follow testing and treatment guidelines. Although HER2+ implies high risk, older patients and those with smaller tumors and node negative disease were most likely to not receive trastuzumab. Documentation of medical reasons for not using trastuzumab was poor, but when provided was consistent with guidelines. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech Genentech Genentech Genentech