Oxaliplatin and capecitabine initially concomitant to radiotherapy then administered in the resting period in high-risk locally advanced rectal cancer.

Abstract

581 Background: Although neoadjuvant chemoradiotherapy (CRT) has dramatically reduced the risk of local recurrence in locally advanced rectal cancer (LARC), it fails to reduce the risk of systemic failure. To enhance systemic control, we develop an alternative approach, combining intense chemotherapy using Oxaliplatin and Capecitabine (XELOX regimen) concomitant to radiation and extending the chemotherapy regimen to the resting period (consolidation chemotherapy) for high risk LARC. The aim of the present study was to evaluate the efficacy and toxicities of this strategy. Methods: Patients with high risk LARC were treated with CRT. Two cycles of XELOX regimen was administered concomitant to radiation. Then an additional cycle of the same regimen was extended to the resting period one week after completion of chemoradiation. Tumor response, toxicities associated with CRT and consolidation chemotherapy, and surgical complications were recorded. Results: Thirty-six patients with high risk LARC were identified treated with the strategy from 2010 to 2012. All patents completed the planned dose of radiation and concurrent chemotherapy, and two patient was unable to complete the consolidation chemotherapy because of grade 3 toxicities. Grade 3 acute toxicities were 2.8% leucopenia, 2.8% diarrhea, and 2.8% radiation dermatitis. All patients underwent optimal surgery with TME, among whom sphincter-saving procedure was performed in 27 patients (75%). There was no peri-operative mortality in this cohort. Seven patients (19.4%) developed postoperative complications. Complete regression (pCR), major regression (nearly pCR), and moderate or minimal regression were achieved in 13 (36.1%), 16 patients (44.4%), and 7 patients (19.5%), respectively. Conclusions: The preliminary results suggest that XELOX regimen concomitant to radiation and extended to the “resting period” after radiation completion are well tolerated. This strategy is associated with high pCR and nearly pCR rates. The promising results warrant further investigation of the impact of consolidation chemotherapy following CRT for LARC in future clinical trials.