Efficacy of anti-EGFR-based treatment (tx) in second-line and beyond according to tumor location (TL) in RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC) patients (pts): A mono-institutional retrospective analysis.

person Raffaella Vivolo Fondazione Policlinico Universitario A.Gemelli-IRCCS-UOC Oncologia Medica, Rome, Italy info_outline Raffaella Vivolo, Maria Alessandra Calegari, Michele Basso, Ina Valeria Zurlo, Brunella Di Stefano, Maria Bensi, Floriana Camarda, Maurizio Martini, Alessandra Cocomazzi, Carmelo Pozzo, Emilio Bria, Lisa Salvatore, Giampaolo Tortora

Authors person Raffaella Vivolo Fondazione Policlinico Universitario A.Gemelli-IRCCS-UOC Oncologia Medica, Rome, Italy info_outline Raffaella Vivolo, Maria Alessandra Calegari, Michele Basso, Ina Valeria Zurlo, Brunella Di Stefano, Maria Bensi, Floriana Camarda, Maurizio Martini, Alessandra Cocomazzi, Carmelo Pozzo, Emilio Bria, Lisa Salvatore, Giampaolo Tortora Organizations Fondazione Policlinico Universitario A.Gemelli-IRCCS-UOC Oncologia Medica, Rome, Italy, Oncologia Medica, Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, Roma, Italy, Fondazione Policlinico Universitario A. Gemelli-IRCCS-UOC Oncologia Medica, Rome, Italy, Fondazione Policlinico Universitario A. Gemelli-IRCCS-Istituto di Anatomia Patologica, Rome, Italy, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy, Fondazione Policlinico Universitario Gemelli IRCCS, Rome, Italy Abstract Disclosures Research Funding Other Background: Right- (R) and left-sided (L) mCRCs exhibit different clinical and molecular features. Several retrospective analyses showed that the survival benefit of anti-EGFR-based tx is limited to RAS/BRAF wt L-sided mCRC pts, with a larger effect in the first-line setting. Few data are available concerning the anti-EGFR efficacy according to TL in 2nd and following lines. Methods: Pts affected by RAS/BRAF wt mCRC treated at our Institution with anti-EGFR-based tx in 2nd and following lines were retrospectively collected. The objective of the analysis was to compare tx activity and efficacy according to TL. Primary endpoint was overall survival (OS); secondary endpoints were progression free survival (PFS) and response rate (RR). Results: A total of 47 RAS/BRAF wt mCRC pts treated with an anti-EGFR-based tx in 2nd and following lines were identified. Of those, 32 (68%) were L-sided and 15 (32%) R-sided, respectively. Pts (age, gender, PS ECOG) and tumor (number of metastatic sites) characteristics and number of tx lines were well balanced between the two 21 pts received anti-EGFR alone, 26 pts anti-EGFR plus CT. mOS was 22.3 in L-sided and 7.3 months in R-sided group (HR 2.3, 95%CI 1.02-5.14, p = 0 .04). At multivariate analysis TL and PS ECOG independently correlated with OS ( p = 0 .02 and p = 0.0089). mPFS was 8.4 and 3.9 months in pts with L-sided and R-sided tumor, respectively (HR 1.3; 95%CI 0.64-2.80, p = 0.43). RR was higher in L-sided compared to R-sided tumor (37.5 vs 13.3) ( p = 0.09). Conclusions: Our analysis, although limited by the small sample and by its retrospective nature, indicates a better OS in L-sided compared to R-sided tumors treated with anti-EGFR-based tx in 2nd and following lines. A prospective validation is warranted.