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Sub-category:
Predictive and Prognostic Factors
Category:
Detection/Diagnosis
Meeting:
2007 Breast Cancer Symposium
Session Type and Session Title:
Oral Abstract Presentation Session B
General Poster Session D
Abstract No:
28
Author(s):
D. T. Ross, C. Kim, G. Tang, O. M. Mejia, R. A. Beck, B. Z. Ring, R. S. Seitz, S. Paik, J. P. Costantino, N. Wolmark
Abstract:
Background: A strong association between disease progression and a novel five antibody IHC test for ER+ breast cancer was previously demonstrated (Ring et al, JCO 2006). As an additional trial of this IHC test, we performed a prospectively designed blinded retrospective study using the combined tamoxifen-treated arms of the NSABP B14 and B20 ER+ N0 trials. We also examined the relationship between treatment with chemotherapy and the IHC test using the tamoxifen plus chemo-treated arm of the B20 trial. Methods: Tissue arrays were constructed in triplicate and stained using five monoclonal antibodies targeting p53, NDRG1, SLC7A5, CEACAM5 and HTF9C. Pre- defined scoring rules and cut-points for risk strata were applied to the 1,007 scored patients (711 in the tamoxifen treated-B14 B20 trials, 296 in the tamoxifen plus chemo-treated B20 trial). RFI was defined as time from entry to any local, regional or distant recurrence. Results: In a univariate Cox model the distribution of recurrence events between the test's risk strata for the ten-year study period was significantly distinct (HR=1.304, 95%:CI 1.08-1.573, p=0.006). In a multivariate model the test was independent of age, tumor size, and menopausal status (p=0.007). Exploratory analysis revealed that the test may have the greatest clinical relevance in patients >60 years old with KM estimates of the proportion recurrence-free of 78.5% for the high-risk, 89% for the moderate-risk, and 92% for the low-risk groups. The IHC test identified high- and low-risk groups that both showed significant improvement upon treatment with cytotoxic chemotherapy. A formal test for interaction between chemo and the risk group was not significant (p=0.107). Conclusion: IHC staining patterns using five selected monoclonal antibodies combined using a predefined algorithm assigns patients to risk strata significantly associated with outcome in ER+ N0 populations. Exploratory analysis suggests that this test may be most useful in clinical decision making for post-menopausal patients and may be able to identify groups of ER+ N0 patients who have greater absolute benefit from adjuvant chemo compared to unstratified patient populations.
 Associated Presentation(s):
Other Abstracts in this Sub-Category:
Abstracts by D. T. Ross:
Presentations by D. T. Ross:
Educational Book Manuscripts by D. T. Ross:
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