Abstract 474P
Background
The objective of this study is to analyse the prognostic and predictive role of CMS developed from an immunophenotypic classifier in patients with mCRC (Trinh A et al. Clin Cancer Res, 2017; 23:387).
Methods
Within the observational study GEMCAD 14-01, 214 patients diagnosed with mCRC who received first line treatment with polychemotherapy +/- targeted therapy were analysed. Tumour biopsies were classified as CMS1, CMS2/3 or CMS4 based on the immunohistochemical expression of 9 antibodies. In the 185 patients in whom the molecular subtype could be determined, clinical characteristics, time to progression (TTP) and overall survival (OS) were evaluated.
Results
89.4% of the cases were classified: CMS1: 3.7%; CMS2/3: 50% and CMS4: 35.6%. With a median follow-up of 48 months (mo), no differences were detected in TTP, OS or response rate between the molecular subtypes. However, the application of GERCOR and Köhne prognostic models have shown prognostic value, finding differences in OS between the different prognostic subgroups (table). Analysing the relationship between TTP and OS with the molecular subtype and the treatments, we observed: 1) In CMS4 patients, oxaliplatin-based treatment is associated with an increase in OS compared to irinotecan-based treatment, 25 vs. 12 mo, (HR 0.42; P<0.05); 2). In patients with CMS2/3, treatment with anti-EGFR is associated with a non-significant increase in OS with a median OS of 27 vs. 19 mo compared to bevacizumab (HR 0.67; P = 0.09).
Conclusions
Classification of CRC molecular subtypes by immunohistochemistry has not been shown to be a prognostic marker, unlike GERCOR and Köhne prognostic classifications. However, CMS can be considered a predictive response marker and could be a tool to optimize the treatment of patients with mCRC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
O. Higuera Gomez: Advisory/Consultancy, Speaker Bureau/Expert testimony: Roche; Advisory/Consultancy: Astrazeneca; Advisory/Consultancy: Amgen. M. Mendiola: Speaker Bureau/Expert testimony: Tesaro; Speaker Bureau/Expert testimony: AstraZeneca. A. Ruiz-Casado: Speaker Bureau/Expert testimony: Roche; Speaker Bureau/Expert testimony: Sanofi; Speaker Bureau/Expert testimony: Bayer; Speaker Bureau/Expert testimony: Merck; Speaker Bureau/Expert testimony: Celgene; Speaker Bureau/Expert testimony: BTG; Speaker Bureau/Expert testimony: Lilly; Speaker Bureau/Expert testimony: Servier. E. Galvez: Speaker Bureau/Expert testimony: Roche; Speaker Bureau/Expert testimony: BMS; Speaker Bureau/Expert testimony: Merck; Speaker Bureau/Expert testimony: Boehringer. J. Aparicio: Advisory/Consultancy: Roche; Advisory/Consultancy: Merck; Advisory/Consultancy: Amgen; Advisory/Consultancy: Sanofi; Advisory/Consultancy: Celgene; Advisory/Consultancy: Servier; Advisory/Consultancy: Bayer. V. Alonso-Orduna: Speaker Bureau/Expert testimony: Merck; Speaker Bureau/Expert testimony: Sanofi; Advisory/Consultancy: Amgen; Advisory/Consultancy: Roche; Advisory/Consultancy: Servier; Advisory/Consultancy: IPSEN; Advisory/Consultancy: Novartis. A. Fernandez Montes: Advisory/Consultancy: Roche; Advisory/Consultancy: Amgen; Advisory/Consultancy: Merck; Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Bayer; Advisory/Consultancy: Lilly; Advisory/Consultancy: Servier; Advisory/Consultancy: Sanofi. J. Maurel: Advisory/Consultancy: Shire; Advisory/Consultancy: Sirtex; Advisory/Consultancy: Servier; Advisory/Consultancy: Pierre-Fabre; Advisory/Consultancy: Advance Medical; Advisory/Consultancy: Astra Zeneca; Advisory/Consultancy: Bayer; Advisory/Consultancy: Sanofi; Advisory/Consultancy: Roche. J. Feliu: Advisory/Consultancy, Research grant/Funding (institution): Amgen; Advisory/Consultancy: IPSEN; Advisory/Consultancy: Eisai; Advisory/Consultancy: Roche; Advisory/Consultancy: Novartis; Advisory/Consultancy: Merck; Advisory/Consultancy: Sirtex. All other authors have declared no conflicts of interest.