268P - Proliferation determined by Ki67 marker defines pathological complete response in a dose-dense neoadjuvant chemotherapy schedule in locally advanced...

Date 01 October 2012
Event ESMO Congress 2012
Session Poster presentation III
Topics Breast Cancer, Early Stage
Pathology/Molecular Biology
Translational Research
Presenter Maria Yessica Plata Fernandez
Authors M.Y. Plata Fernandez1, A. Sanchez-MuÑoz2, A. JaÉn-Morago1, M. Lomas-Garrido1, M. Fernández1, C. Llacer2, M. Fernández1, N. Ribelles2, E. Alba-Conejo2, P. Sanchez-Rovira1
  • 1Oncología Médica, Complejo Hospitalario de Jaén, 23007 - Jaén/ES
  • 2Oncology, HOSPITAL UNIVERSITARIO VIRGEN DE LA VICTORIA, 29010 - MALAGA/ES

Abstract

Background

The value of Ki67 proliferation biomarker during neoadjuvant chemotherapy (NC) is less clear than with neoadjuvant endocrine therapy. We study the role of proliferation according to Ki67 marker measured by immunohistochemistry (IHC) as a predictive factor of pathological complete response to NC.

Methods

From May 2002 to June 2005, 127 pts diagnosed as stage II-III, including inflammatory tumors, breast cancer patients (pts) received one of the 2 NC regimens every 2 weeks with prophylactic growth factor support. Study A: adriamicin 40mg/m2 d1 plus P 150mg/m2-G 2000 mg/m2 d2 for 6 cycles (n = 54); study B: epirubicin 90 mg/m2-cyclophophamide 600 mg/m2 d1 for 3 cycles, followed by a second sequence with paclitaxel (P) 150 mg/m2- gemcitabine (G) 2500 mg/m2 d1 +/- trastuzumab 2mg/kg/wk according to status Her2 (n= 73). In study A pts did not receive trastuzumab regardless of Her2 status. Ki67 was centrally assessed by IHC (Master Diagnostica clon SP6). Tumors were considered to have high proliferation rates (Ki67) if ≥ 20% of cell nuclei stained positive. Median age was 48 years. Her2+ was observed in 31%, HR negative 34%, grade III 46% and high Ki67 47%. Pathological complete response (pCR) defined as absence of invasive cells in breast and lymph node was achieved in 35 pts (28%). Univariate and multivariate logistic regression models were used to study the association of each clinical-pathological variable with pCR.

Results

High Ki67 was the main predictive factor of pCR to NC. In the univariate analysis histological grade (p = 0.001), HR (p < 0.001), Ki67 (p = 0.001) and p53 (p < 0.001) were statistically associated with pCR. A multivariate logistic regression showed than only high Ki67 (p = 0.02; OR = 5.5 CI95% 1.2- 18) and HR (p = 0.045; OR = 0.25 CI95% 0.05-0.97) were predictive for pCR.

Conclusion

High proliferation determined by ki67 marker is an independent predictive factor for pCR in locally advanced breast cancer patients treated in two dose-dense NC schedules.

Disclosure

All authors have declared no conflicts of interest.