652 - Primary resistance to first-line bevacizumab in metastatic colorectal cancer: implications on prognosis

Date 28 September 2012
Event ESMO Congress 2012
Session Publication Only
Topics Anti-Cancer Agents & Biologic Therapy
Colon Cancer
Rectal Cancer
Presenter Elena Maccaroni
Authors E. Maccaroni1, R. Giampieri2, M. Scartozzi2, M. Del Prete2, A. Bittoni3, L. Faloppi4, M. Bianconi4, S. Cascinu5
  • 1AOU Ospedali Riuniti Ancona Università Politecnica delle Marche, 60126 - Ancona/IT
  • 2Clinica Di Oncologia Medica, AOU Ospedali Riuniti Ancona Università Politecnica delle Marche, 60126 - Ancona/IT
  • 3Clinica Di Oncologia Medica, Ospedali Riuniti di Ancona, 60019 - Ancona/IT
  • 4Clinica Di Oncologia Medica, AOU Ospedali Riuniti AnconaUniversit, IT-60126 - Ancona/IT
  • 5Dipartimento Di Medicina Clinica E Biotecnologie A, University of Ancona, 60020 - Ancona/IT

Abstract

A role of Bevacizumab after first-line failure is currently in study. We focused our analysis on patients who progressed directly under first-line Bevacizumab and assessed if lack of effect could be managed with second line chemotherapy. We conducted a retrospective analysis on metastatic colorectal cancer patients treated in the 2008-2011 period with first-line Bevacizumab. Stratification criteria were sex, age, performance status, metastatic sites, metachronous vs synchronous metastases, chemotherapy backbone, K-ras status. Chest-abdomen CT scan was performed every 3 months. Response was scored according to RECIST criteria. Progression free survival and overall survival were defined as usual. 146 patients were eligible for analysis. 60 (41%) partial responses, 54 (37%) stable disease and 32 (22%) progressions were seen. Median overall survival was 18.5 months and median progression free survival was 8.2 months. No significant differences were seen in regards to stratification criteria for different response groups. Progression free survival for patients who achieved a partial response, a stable disease or progression were respectively 10.6 vs 8.5 vs 3.0 months (p < 0.0001). Overall survival for patients who achieved a partial response, a stable disease or progression were respectively 21.3 vs 19.7 vs 9.1 months (p < 0.0001). All 32 patients who directly progressed under Bevacizumab based-treatment received a second line chemotherapy regimen and in 16 (50%) it was anti-EGFR based (either Cetuximab or Panitumumab). Remaining 16 patients received standard chemotherapy. Only a trend towards better overall survival for anti-EGFR based regimens (10 vs 7.78 months, p = 0.26) was seen. Monoclonal antibodies increased expected survival for metastatic colorectal cancer, reaching 20 months and more in historical series. In our analysis a dismal survival of 9.1 months was seen for patients who directly progress under first-line Bevacizumab, regardless of the treatment received in second-line. It is thus suggested that, even if overall survival is the primary end-point of therapy, disease control rate should also be considered, because failure of first-line treatment may jeopardize global outcome.

Disclosure

All authors have declared no conflicts of interest.