Exploring the effect of primary tumor sidedness on therapeutic efficacy across treatment lines in patients with metastatic colorectal cancer: analysis of FIRE-3 (AIOKRK0306)

• Published in: Oncotarget 2017-12, Vol.8 (62), p.105749-105760
• Main Authors: Modest, Dominik Paul, Stintzing, Sebastian, von Weikersthal, Ludwig Fischer, Decker, Thomas, Kiani, Alexander, Vehling-Kaiser, Ursula, Al-Batran, Salah-Eddin, Heintges, Tobias, Kahl, Christoph, Seipelt, Gernot, Kullmann, Frank, Scheithauer, Werner, Moehler, Markus, Holch, Julian Walter, von Einem, Jobst Christian, Held, Swantje, Heinemann, Volker
• Format: Article
• Language: English
• Subjects: Research Paper
• ISSN: 1949-2553; 1949-2553
• DOI: 10.18632/oncotarget.22396

To assess the impact of primary tumor sidedness on outcome of patients with metastatic colorectal cancer (mCRC) across treatment lines. Patients of the FIRE-3 trial (initial FOLFIRI plus either cetuximab or bevacizumab) were separately evaluated according to primary tumor site differentiating left-sided (LPT) from right-sided primary tumors (RPT). Efficacy (i.e. progression-free survival (PFS2nd) and overall survival (OS2nd) of second-line therapy) was evaluated by Kaplan-Meier method and compared by log rank test as well as Cox regression analyses. All analyses were also reported according to drug sequences. 411 of 592 patients (69%) with KRAS exon 2 wild-type tumors received 2nd-line therapy has and had available information on primary tumor location, of those 309 patients (75%) presented with LPT. In patients with LPT, PFS2nd was markedly longer than in patients with RPT (6.0 months [95% CI 5.5-6.5] versus 3.8 months [95% CI 2.5-5.2], hazard ratio: 0.61 [95% CI 0.47-0.78], P