Palliative oxaliplatin-based chemotherapy after exposure to oxaliplatin in the adjuvant setting for colon cancer.

Abstract

753 Background: Little is known regarding the efficacy of oxaliplatin-based chemotherapy for metastatic colon cancer patients who have already received adjuvant oxaliplatin-based chemotherapy. Methods: We retrospectively reviewed 22 consecutive patients who developed recurrence after adjuvant oxaliplatin-based chemotherapy for stage III colon cancer and received another course of oxaliplatin-based chemotherapy for their metastatic disease. The main endpoint was progression-free survival (PFS). Results: 635 patients received oxaliplatin-based chemotherapy for stage III colon cancer at the British Columbia Cancer Agency from 2006 to 2011. 176 pts recurred, 22 (12.5%) of whom were re-exposed to oxaliplatin in the metastatic scenario. Oxaliplatin in combination with fluoropyrimidine was given as first line in 3 pts (13.6%), as second line in 14 (63.6%), and third line in 5 (22.7%). Median time from the last cycle of adjuvant oxaliplatin-based chemotherapy to the first cycle of palliative oxaliplatin-based chemotherapy was 44.3 months. Median PFS and OS were 3.3 (95% CI 1.4-5.1) and 10.0 months (95% CI 5.3-14.6), respectively. There was no difference in PFS for patients who were re-exposed to oxaliplatin in less than 36 months or later than that (3.6 versus 3.1 months, p=0.793, HR=0.88). Conclusions: In this population-based study, only a small proportion of pts who recurred after oxaliplatin-based adjuvant therapy received oxaliplatin in the metastatic setting. Re-exposure of oxaliplatin in combination with fluoropyrimidine is associated with only modest PFS benefit. Larger studies evaluating the role of oxaliplatin re-exposure are needed.