In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 31, No. 26_suppl ( 2013-09-10), p. 61-61
Abstract:
61 Background: HER2 overexpression is associated with an increased risk of LRR after mastectomy in the era prior to the use of adjuvant trastuzumab. The purpose of this study was to examine the effect of adjuvant trastuzumab on rates of LRR and whether this effect varied with the use of PMRT. Methods: From our institutional database, 474 women with Stage I-III HER2+ invasive breast cancer treated with mastectomy +/- adjuvant therapy from 1999-2007 were identified. Those patients lost to follow-up, treated with lapatinib, or diagnosed between 5/2004 to 5/2005 (when trastuzumab prescribing practices varied) were excluded; leaving 395 in the final study population. Two cohorts were compared: 139 women who received trastuzumab (5/2005-12/2007) and 256 women who did not (prior to 5/2005). Competing risks analyses were used to estimate cumulative incidence of LRR. Competing risks regression was used to evaluate the association between treatment factors and LRR. To minimize lead-time bias, patient data was censored at 5 years after mastectomy in both groups. Results: There were 18 LRRs in the entire cohort (16 no trastuzumab, 2 trastuzumab). Women in the no trastuzumab group were less likely to be node positive, receive chemotherapy or PMRT (all p 〈 0.001). The hazard ratio for LRR was 0.218in the trastuzumab group (p= 0.04, 95% C.I. 0.05-0.94) with a 5-year risk of LRR of 1.5% in the trastuzumab versus 6.6% in the no trastuzumab group. After adjusting for PMRT and chemotherapy receipt, trastuzumab trended towards significance in decreasing LRR (p= 0.063). On subset analysis of 139 women who received PMRT, trastuzumab significantly reduced LRR (7.3% no trastuzumab, 0% trastuzumab, p=0.025). Among those who did not receive PMRT (256), trastuzumab did not significantly decrease LRR (6.3% no trastuzumab, 2.9 % trastuzumab, p=0.28). Conclusions: Adjuvant trastuzumab significantly reduced LRR in women with HER2+ breast cancer who received PMRT. A trend toward decreased LRR was observed in the entire population, but did not reach statistical significance, suggesting that the benefit is greater in HER2+ patients receiving multimodality therapy.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2013.31.26_suppl.61
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2013
detail.hit.zdb_id:
2005181-5
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