Changes in PgR and Ki-67 in residual tumour and outcome of breast cancer patients treated with neoadjuvant chemotherapy
Menée en Italie à partir de données portant sur 904 patientes atteintes d'un cancer du sein traité par chimiothérapie puis chirurgie entre 1999 et 2011, cette étude évalue l'association entre l'évolution du niveau d'expression tumorale du récepteur PgR et de l'antigène Ki-67 et la survie sans maladie des patientes
Background : Limited data are available on the prognostic value of changes in the biological features of residual tumours following neoadjuvant therapies in breast cancer patients.
Patients and Methods : We collected information through the institutional clinical database on all consecutive breast cancer patients treated with neoadjuvant chemotherapy at the European Institute of Oncology (IEO), Milan, Italy, between 1999 and 2011. We selected patients who did not achieve pathological complete response (pCR) at final surgery. All patients had a pathological evaluation, including ER, PgR, HER2 protein and Ki-67 expression performed at the IEO both at diagnostic core biopsy and at final surgery.
Results : We identified a total of 904 patients. The 5% of patients who were ER-positive at diagnostic biopsy had ER-negative residual tumour at final surgery. For PgR expression, 67% of the patients, whose tumours had a PgR> 20% at diagnostic biopsy had a PgR<20% at final surgery. The Ki-67 expression changed from >20% to <20% in 40% of the patients. At the multivariate analysis the decrease of PgR -immunoreactive cells correlated with improved outcome in terms of DFS (HR 0.73; CI 0.54-1.00 p 0.046). In addition, the decrease of Ki-67 expression to<20% of the cells at final surgery was found to be associated with better outcome both in terms of DFS (HR 0.52; CI 0.40-0.68 p <0.0001) and OS (0.45 CI 0.32-0.64 p<0.0001)
Conclusion : The decrease of PgR and Ki-67 expression after preoperative chemotherapy has a prognostic role in breast cancer patients with residual disease.
Annals of Oncology , résumé, 2014