Abstract P5-18-05: The Promher Study: An observational Italian study on HER2+ve, pT1a-b, pN0, M0 breast cancer (BC) patients (pts)

Background. The management of small (≤ 1 cm), node-negative, HER2+ve BC is controversial, since data from randomized clinical trials specifically addressing the benefit of adjuvant systemic treatment with or without Trastuzumab in this setting are still lacking. The aims of this retrospective study are to assess how pts are managed in routinary clinical practice in Italy, whether clinical or biological features may influence the choice of adjuvant systemic therapy and if there is any difference in the outcome between treated and not treated pts. Patients and methods. Data of 268 consecutive pts who underwent surgery from January 2007 to December 2012 for HER2+ve, pT1a-b pN0 BC, were collected from 25 Italian centres. Descriptive statistical analyses and multivariate logistic regression models were used, with the aim of investigating the relationship between the baseline clinical and biological features and the adjuvant treatment strategy. Results. Pts characteristics were: median age 57, 69% postmenopausal status, 77% had conservative surgery, 32% pT1a, 68% pT1b, 48% G3, 66% ER+ve, 75% Ki67 ≥14%. Ninety percent of pts received adjuvant systemic therapy: 19% hormone therapy (HT) alone, 3% chemotherapy (CT) +/- HT, 64% Trastuzumab + CT +/- HT and 4% Trastuzumab + HT. At the multivariate analysis, the odds of being treated with adjuvant systemic therapy with or without Trastuzumab, resulted higher in presence of conservative surgery (p=0.002), pT1b (p Conclusion. This preliminary analysis shows that in Italy the majority of these pts received systemic adjuvant treatment and about 2/3 were treated with Trastuzumab. Pathological tumor size (pT1b) and negative hormone receptor status represent the main factors influencing the choice of including Trastuzumab in the adjuvant treatment. Survival data are still not mature to drive definitive conclusions about outcome. Citation Format: Stefania Gori, Monica Turazza, Simona Duranti, Elena Fiorio, Jennifer Foglietta, Marcella Gulisano, Ilaria Marcon, Marta Gubbiotti, Maria Giovanna Cavazzini, Simon Spazzapan, Valeria De Simone, Giancarlo Bisagni, Chiara Saggia, Luigi Cavanna, Emilio Bria, Laura Iezzi, Elisabetta Cretella, Patrizia Vici, Daniele Santini, Alessandra Fabi, Ornella Garrone, Antonella Ferro, Silvana Saracchini, Lucia Evangelisti, Sandro Barni, Lucia Mentuccia, Lucio Laudadio, Alessandro Inno, Gianluigi Lunardi, Francesca Coati, Luca Boni. The Promher Study: An observational Italian study on HER2+ve, pT1a-b, pN0, M0 breast cancer (BC) patients (pts) [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-18-05.