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Abstract P2-09-11: PAM50 intrinsic subtyping as a predictor of pathological complete response to neoadjuvant trastuzumab-based chemotherapy in early HER2-positive breast cancer
- Source :
- Cancer Research. 78:P2-09
- Publication Year :
- 2018
- Publisher :
- American Association for Cancer Research (AACR), 2018.
-
Abstract
- Background: HER2-positive breast cancer (BC) is a heterogeneous disease from a clinical and biological perspective. Intrinsic subtype defined by gene expression has an important role in determining response to treatment, as seen in several neoadjuvant trials (e.g. CALGB40601, CherLOB, NeoALTTO and PAMELA). However, limited data exist in an off-trial setting. The objective of this study was to evaluate the association of intrinsic subtypes with pathological completed response (pCR) and survival outcomes of a series of HER2-positive patients (pts) homogeneously treated with trastuzumab-based primary chemotherapy (PC) in a single comprehensive cancer center. Methods: Clinical-pathological data were evaluated in a series of 150 consecutive stage II-IIIC (T4d included) HER2-positive BC pts treated in ICO-Hospitalet (Spain) from August-2009 to December-2012 with weekly paclitaxel x12 followed by FEC/3w x 4 and concurrent trastuzumab for a total of 24w. HER2-positivity was considered according to ASCO-CAP 2007 guidelines. pCR was defined as ypT0/isypN0. The expression of 105 BC-related genes, including the PAM50 genes, was determined in baseline and residual formalin-fixed paraffin-embedded tumor samples using the nCounter platform. Intrinsic subtypes were determined by the research-based PAM50 gene expression predictor. Association of variables with pCR or disease-free survival (DFS) was evaluated using logistic regression analyses and cox proportional hazard models.All statistical tests were two-sided and considered significant when p≤0.05. Results: Most pts had T2 (64%) and T4 (20%) tumors and clinically node-positive disease (77%). 53% had hormonal receptor (HR)+ disease. 84 of the 150pts (56%) achieved a pCR; HR-neg was associated with higher pCR rates (72.5%vs 42% in HR+ P Conclusions: In this consecutive series of HER2-positive BCtreated homogeneously with neoadjuvant trastuzumab-based PC, all of the main intrinsic molecular subtypes were identified with a predominance of HER2-E. HER2-E was significantly associated with pCR and survival outcome. Distribution of the intrinsic subtypes in residual disease differed from untreated tumors. Citation Format: Pernas S, Petit A, Climent F, Pare L, Perez-Martin J, Ventura L, Galvan P, Falo C, Morilla I, Fernandez-Ortega A, Stradella A, Pascual T, Gil-Gil M, Prat A. PAM50 intrinsic subtyping as a predictor of pathological complete response to neoadjuvant trastuzumab-based chemotherapy in early HER2-positive breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-09-11.
- Subjects :
- 0301 basic medicine
Oncology
Cancer Research
medicine.medical_specialty
Chemotherapy
business.industry
medicine.medical_treatment
Cancer
Disease
medicine.disease
Subtyping
03 medical and health sciences
030104 developmental biology
0302 clinical medicine
Breast cancer
Trastuzumab
030220 oncology & carcinogenesis
Internal medicine
Medicine
Stage (cooking)
business
Pathological
medicine.drug
Subjects
Details
- ISSN :
- 15387445 and 00085472
- Volume :
- 78
- Database :
- OpenAIRE
- Journal :
- Cancer Research
- Accession number :
- edsair.doi...........e40abed5bc710da47e5ecd8243f03e27