Rechallenge of oxaliplatin-containing regimens in the third- or later-line therapy for patients with heavily treated metastatic colorectal cancer

Purpose: The third-or later-line therapy available often yield poor survival benefit in patients metastatic colorectal cancer (mCRC). The retrospective study aimed to evaluate efficacy of rechallenge of oxaliplatin-containing regimens. Patients and methods: Patients with mCRC who progressed from fluoropyrimidine, oxaliplatin, and irinotecan in the first-and second-line chemotherapy, were treated by reexposure to oxaliplatin-containing regimen. Patients treated by anti-epidermal growth factor receptor (EGFR) antibodies with irinotecan were included in the control arm. Results: Ninety-five and 29 patients were treated with either oxaliplatin reexposure or anti-EGFR antibodies with irinotecan, respectively, as the third-or later-line therapy. The median time to treatment failure (TTF) and overall survival (OS) was 3.77 and 12.17 months in the oxaliplatin arm, with 4.77 months of TTF and 11.37 months of OS in the control arm; there was no significance between the 2 arms (p>0.05). Oxaliplatin reexposure resulted in 6.3% objective response rate with no complete response, 6 partial response, 39 stable disease, and 37 progressive disease. The disease control rate was 47.4% (45/95). The multivariate analysis found that patients who achieved disease control by oxaliplatin reexposure had a superior TTF (6.13 vs 1.7 months, p<0.001) and OS (15.73 vs 6.27 months, p<0.001) compared with those presenting with progressive disease. Conclusion: This study showed that rechallenge of oxaliplatin-containing chemotherapy in the third-or later-line therapy may lead to tumor control and improved survival in mCRC patients, which was equivalent to that of anti-EGFR antibodies with irinotecan. Clinical significance: Rechallenge of oxaliplatin-containing regimens in the third-or later-line of therapy is a common practice, despite few evidence available. The present study found that rechallenge of oxaliplatin-containing regimens produced equivalent tumor control and survival benefit to that of anti-EGFR antibodies with irinotecan in mCRC.