Abstract P1-08-06: SToRM: A prospective clinical trial of 1502 metastatic breast cancer (mBC) patients with detail of clinical presentation, molecular subtype, treatment modalities, prognosis and GWAS genotyping
Authors: Bachelot T , Lavergne E , Romieu G , Rios M , Heudel P-E , Roemer-Becuwe C , Jouannaud C , Tredan O , Chaigneau L , Arnedos M , Orfeuvre H , Petit T , Quenel-Tueux N , Jacquin J-P , Ferrero J-M , Moullet I , Abadie-Lacourtoisie S , Penault-Llorca F , Blanc E , Cox D 
Published: May 2016

Background: Due to better molecular classification and new treatment options, epidemiology and prognosis of mBC is rapidly changing. Clinical data extracted from randomized studies are only relevant to specific subpopulations and retrospective studies are prone to selection bias. SToRM is a prospective clinical trial that aims to create a cohort of 1500 mBC patients, with the ultimate goal of identifying germ line polymorphisms associated with prognosis of breast cancer (BC) and response to treatment in the metastatic phase.

Material and methods: Any newly (within 1 year) diagnosed mBC patients were eligible. Whole blood samples were drawn and germline DNA extracted for genetic analysis. Extensive epidemiologic data, disease history from primary diagnosis to metastatic spread, pathological characteristics and ER, PR and HER2 status were collected. Patients are prospectively followed until death. Genotyping using the HumanCoreExome chipset from Illumina is currently underway and will be completed in early summer 2015.

Results: 1502 patients were included from March 2012 to May 2014 from 71 French institutions. Median age at metastatic relapse was 60 years (range 26-93). Median time from primary diagnosis to metastatic relapse was 30 months (range 0-473) with 24% of patients already metastatic at initial diagnosis. 78% of patients were ER+, 18% were HER2+ and only 16% were triple negative. Molecular subtype classification derived from pathological data following St Gallen consensus recommendations is presented below:

 n (%)Luminal A like261 (22.2%)Luminal B like HER2 negative476 (40.5%)Luminal B like HER2 positive134 (11.4%)HER2 positive non Luminal (ER-)111 (9.5%)Triple negative193 (16.4%)Missing data327

64% of the patients had received previous adjuvant treatment, among which 81% received adjuvant chemotherapy and 9% trastuzumab.

At metastatic relapse, loco-regional progression, liver, lung and bone metastasis were documented in 301 (20%), 494 (33%), 410 (27%) and 1017 (68%) patients respectively. 313 patients (21%) had bone only metastatic disease. First line treatment included: chemotherapy (71%), endocrine therapy (50%) and anti-HER2 treatments (17%). Survival data will be presented at the meeting.

Conclusion: Despite a theoretically better prognosis and widespread use of adjuvant hormonal treatment, ER+/HER2- breast cancer still account for more than 60% of mBC. The proportion of patients with HER2+ disease (18%) and triple negative disease (16%) is consistent with percentages observed in early BC populations. In comparison with a cohort of "cured", localized cancer, such as the SIGNAL/PHARE study, GWAS analysis will allow for the identification of genetic polymorphisms correlated with treatment resistance. Fundamentally, such variants will provide insight into the molecular mechanisms responsible for host-genetic influence on BC progression. From a clinical perspective, genetic variants that predispose to metastatic disease can serve as stratification variables in future clinical trials, particularly as the development of new treatment options for resistant BC is needed.

Citation Format: Bachelot T, Lavergne E, Romieu G, Rios M, Heudel P-E, Roemer-Becuwe C, Jouannaud C, Tredan O, Chaigneau L, Arnedos M, Orfeuvre H, Petit T, Quenel-Tueux N, Jacquin J-P, Ferrero J-M, Moullet I, Abadie-Lacourtoisie S, Penault-Llorca F, Blanc E, Cox D. SToRM: A prospective clinical trial of 1502 metastatic breast cancer (mBC) patients with detail of clinical presentation, molecular subtype, treatment modalities, prognosis and GWAS genotyping. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-08-06.