P3-059 - Necessity of oxaliplatin in adjuvant chemotherapy for stage IIIb colorectal cancer

Abstract

Oxaliplatin (l-OHP) conbined regimen is the standard adjuvant chemotherapy for stage III colorectal cancer (CRC) patients. However, there is little evidence limted to stage IIIb. We evaluated the necessity l-OHP concomitant use in adjuvant chemotherapy for stage IIIb CRC patients. In the patients with Stage IIIb (Japanese Classification of Colorectal Carcinoma 8th Edition) CRC who underwent curative resection in our department from 2000 until 2013, fourteen patients treated with l-OHP combined regimen as postoperative adjuvant chemotherapy (group A) were compared with 27 patients without l-OHP (group B). In addition, we performed multivariate analysis to identify the poor prognostic factors for stage IIIb CRC. The median total dose of l-OHP in group A was 1115 mg/body and the dose intensity was 77.8%. In Group A, 11 cases (78.6%) had neuropathy of Grade 2 or higher, and even after 1 year after discontinuation of administration, 4 neuropathies remained in 4 cases (Grade 2: 1 case, Grade 1: 3 cases). The 5-year diseasee-free survival rate (DFS) and overall survival rate (OS) in Group A were 56.3% and 85.7%, respectively (median follow-up periods: 5.6 years). The 5-year DFS and OS of group B were 60.5% and 72.4%, respectively. There were no significant differences between both groups. In multivariate analysis, higher preoperative serum CEA level (HR: 9.623) and male (HR: 7.223) were significant in DFS and male (HR: 5.121) was a significant prognostic factor in OS. There is no additional effect of l-OHP for adjuvant chemotherapy in Stage IIIb CRC. It seems that new treatment strategies such as preoperative chemotherapy are necessary for higher preoperative serum CEA cases.