PLoS ONE (Jan 2012)

Role of Kras status in patients with metastatic colorectal cancer receiving first-line chemotherapy plus bevacizumab: a TTD group cooperative study.

  • Eduardo Díaz-Rubio,
  • Auxiliadora Gómez-España,
  • Bartomeu Massutí,
  • Javier Sastre,
  • Margarita Reboredo,
  • José Luis Manzano,
  • Fernando Rivera,
  • M José Safont,
  • Clara Montagut,
  • Encarnación González,
  • Manuel Benavides,
  • Eugenio Marcuello,
  • Andrés Cervantes,
  • Purificación Martínez de Prado,
  • Carlos Fernández-Martos,
  • Antonio Arrivi,
  • Inmaculada Bando,
  • Enrique Aranda,
  • Spanish Cooperative Group for the Treatment of Digestive Tumors (TTD)

DOI
https://doi.org/10.1371/journal.pone.0047345
Journal volume & issue
Vol. 7, no. 10
p. e47345

Abstract

Read online

In the MACRO study, patients with metastatic colorectal cancer (mCRC) were randomised to first-line treatment with 6 cycles of capecitabine and oxaliplatin (XELOX) plus bevacizumab followed by either single-agent bevacizumab or XELOX plus bevacizumab until disease progression. An additional retrospective analysis was performed to define the prognostic value of tumour KRAS status on progression-free survival (PFS), overall survival (OS) and response rates.KRAS data (tumour KRAS status and type of mutation) were collected by questionnaire from participating centres that performed KRAS analyses. These data were then cross-referenced with efficacy data for relevant patients in the MACRO study database. KRAS status was analysed in 394 of the 480 patients (82.1%) in the MACRO study. Wild-type (WT) KRAS tumours were found in 219 patients (56%) and mutant (MT) KRAS in 175 patients (44%). Median PFS was 10.9 months for patients with WT KRAS and 9.4 months for patients with MT KRAS tumours (p=0.0038; HR: 1.40; 95% CI:1.12-1.77). The difference in OS was also significant: 26.7 months versus 18.0 months for WT versus MT KRAS, respectively (p=0.0002; HR: 1.55; 95% CI: 1.23-1.96). Univariate and multivariate analyses showed that KRAS was an independent variable for both PFS and OS. Responses were observed in 126 patients (57.5%) with WT KRAS tumours and 76 patients (43.4%) with MT KRAS tumours (p=0.0054; OR: 1.77; 95% CI: 1.18-2.64).This analysis of the MACRO study suggests a prognostic role for tumour KRAS status in patients with mCRC treated with XELOX plus bevacizumab. For both PFS and OS, KRAS status was an independent factor in univariate and multivariate analyses.