The prognostic significance of Ki67 before and after neoadjuvant chemotherapy in breast cancer

Robin L. Jones (1) , Janine Salter (1) , Roger A'Hern (2) , Ash Nerurkar (3) , Marina Parton (3) , Jorge S. Reis-Filho (4) , Ian E. Smith (3) , Mitchell Dowsett (1)

1 Academic Department of Biochemistry
2 Institute of Cancer Research Clinical Trials and Statistics Unit
3 Breast Unit
4 Breakthrough Breast Cancer Centre

To compare the prognostic significance of proliferation, as assessed by Ki67 expression, in breast cancer before and after neoadjuvant chemotherapy. A retrospective search of a prospectively maintained clinical database was performed to identify patients treated with neoadjuvant chemotherapy at the Royal Marsden Hospital. The expression of Ki67 was assessed using immunohistochemistry in pre-therapy core-needle biopsy and post-therapy surgical excision specimens. The following factors were considered pre- and post-chemotherapy for their relationship with relapse-free and overall survival: age, menstrual status, T and N stage, pre-therapy operability, Ki67, ER, PgR, HER2, grade, histological subtype, vascular invasion, clinical response, chemotherapy regimen, type of surgery performed, adjuvant therapy, pathological tumour size and nodal involvement. In a matched cohort of 103 patients, on multivariate analysis of relapse-free survival, post-therapy Ki67 was the only significant independent prognostic factor. On multivariate analysis for overall survival, both pre- and excision Ki67 were significant independent predictors but the latter showed a stronger prognostic impact. The highest and lowest tertiles of excision Ki67 had different prognosis for both 5-year relapse-free (27% vs. 77%) and overall (39% and 93%) survival. In a cohort of 284 patients with only excision samples, post-therapy Ki67 was a significant independent prognostic factor on multivariate analysis. Post-chemotherapy Ki67 is a strong predictor of outcome for patients not achieving a pathological complete response.

Mots clés: Breast cancer; Neoadjuvant chemotherapy; Post-therapy proliferation

Robin L. Jones, Janine Salter, Roger A'Hern, Ash Nerurkar, Marina Parton, et al.. The prognostic significance of Ki67 before and after neoadjuvant chemotherapy in breast cancer. Breast Cancer Research and Treatment, 2008, 116 (1), pp.53-68. ⟨10.1007/s10549-008-0081-7⟩. ⟨hal-00478239⟩