Reinduction of oxaliplatin-based chemotherapy after exposure to oxaliplatin in adjuvant setting for colorectal cancer.

Abstract

755 Background: Oxaliplatin-based chemotherapy is commonly used chemotherapy in the adjuvant setting for colorectal cancer patients. In clinical practice, those patients may be retreated with oxaliplatin after relapse. The efficacy and predictive factor of oxaliplatin re-treatment are little known. Methods: We carried out a retrospective study of 53 consecutive patients who underwent surgery and adjuvant FOLFOX chemotherapy and who were re-treated oxaliplatin-based chemotherapy after relapse at Yonsei Cancer Center from April 2009 through October 2015. The main end-point was progression-free survival (PFS). Results: Among enrolled patients, 33 (62.2%) received curative resection in initially non-metastatic setting and the other 20 (37.7%) did R0 resection including metastasectomy in stage 4 at the time of previous oxaliplatin treatment. Median time from last cycle of adjuvant FOLFOX to the first cycle of palliative oxaliplatin based chemotherapy was 31.5 months. Palliative oxaliplatin was given as second and third or later in 37 (69.8%) and 16 (30.2%) patients respectively. Median PFS and overall survival (OS) were 5.1 and 17.5 months. Response rate and disease control rate to palliative oxaliplatin based treatment were 17.0 % and 66.0%. Patients with both shorter interval from first oxaliplatin exposure to recurrence (<12 months) and shorter interval from recurrence to oxaliplatin re-exposure (<18 months) experienced shorter PFS significantly compared to those who did not (2.8 vs. 7.3m, p = 0.004). It was an independent predictive factor for PFS in addition to use of targeted agent in multivaviate analysis. Conclusions: In this study, re-treatment with oxaliplatin based chemotherapy after recurrence demonstrated modest clinical efficacy. Non-use of targeted agent and both shorter interval from first oxaliplatin exposure to recurrence and shorter interval from recurrence to oxaliplatin re-exposure are poor predictive factors for PFS.