B Sigal, Christel Breton-Callu, Emmanuelle Fourme, Laurence Venat-Bouvet, Jérôme Lemonnier, N Quenel-Tueux, Thibault De La Motte Rouge, Jean-Yves Pierga, Marie-Ange Mouret-Reynier, Simone Mathoulin-Pélissier, Thomas Bachelot, Florence Lerebours, Hervé Bonnefoi, Véronique Becette, Gaëtan MacGrogan, Sofia Rivera, Marina Pulido, Christine Tunon de Lara, Marc Debled, Florence Dalenc, Département d'Oncologie Médicale [Centre René-Huguenin, Saint-Cloud], Hôpital René HUGUENIN (Saint-Cloud), CIC Bordeaux, Université Bordeaux Segalen - Bordeaux 2-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de Veille Sanitaire, Institut national de veille sanitaire, Service d'Oncologie Médicale, Institut Bergonié [Bordeaux], UNICANCER-UNICANCER, Validation et identification de nouvelles cibles en oncologie (VINCO), UNICANCER-UNICANCER-Université Bordeaux Segalen - Bordeaux 2-Institut National de la Santé et de la Recherche Médicale (INSERM), Radiothérapie Moléculaire et Innovation Thérapeutique (RaMo-IT), Institut Gustave Roussy (IGR)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Paris-Saclay, Imagerie Moléculaire et Stratégies Théranostiques (IMoST), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), Centre Jean Perrin [Clermont-Ferrand] (UNICANCER/CJP), UNICANCER, Service de Chirurgie, Institut Curie [Paris], Service d'Oncologie médicale [CHU Limoges], CHU Limoges, Plateforme de génétique moléculaire des cancers d'Aquitaine, Bordeaux population health (BPH), Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre Eugène Marquis (CRLCC), Institut Claudius Regaud, Oncogénèse et progression tumorale, Centre Léon Bérard [Lyon]-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de la Santé et de la Recherche Médicale (INSERM), UNICANCER [Paris], and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)
Background Few data are available on survival and predictive factors in early breast cancer (BC) patients treated with neoadjuvant endocrine therapy (NET). Methods This is a pooled analysis of two multicentre, randomised non-comparative phase 2 clinical trials evaluating neoadjuvant anastrozole and fulvestrant efficacy for postmenopausal HR+/HER2- breast cancer patients: HORGEN (NCT00871858) and CARMINA02 (NCT00629616) studies. Results In total, 236 patients were included in CARMINA02 and HORGEN trials. Modified intention-to-treat analysis was available for 217 patients. Median follow-up was 65.2 months. Relapse-free survival (RFS) and overall survival (OS) at 5 years were 83.7% (95% CI: 77.9–88) and 92.7% (95% CI: 88.2–95.6), respectively, with no difference between treatment arms. On univariate analysis, tumour staging (T2 vs T3–4; p = 0.0001), Ki-67 at surgery (≤10% vs >10%; p = 0.0093), pathological tumour size (pT1–2 vs pT3–4; p = 0.0012) and node status (pN negative vs positive; p = 0.007), adjuvant chemotherapy (p = 0.0167) and PEPI score (PEPI group I + II vs III; p = 0.0004) were associated with RFS. No events were observed in patients with pathological response according to the Sataloff classification. Multivariate analysis showed that preoperative endocrine prognostic index (PEPI) group III was associated with significantly worse RFS (p = 0.0069, hazard ratio = 3.33 (95% CI: 1.39–7.98)). Conclusions Postmenopausal HR+/HER2- breast cancer patients receiving NET generally have a favourable outcome. The PEPI score identifies a subset of patients of poorer prognosis who are candidates for further additional treatment.