P-0218 - Timing and Regimens of Adjuvant Therapy for Resected Stage II and III colon Cancer

Date 28 June 2014
Event World GI 2014
Session Poster Session
Topics Anti-Cancer Agents & Biologic Therapy
Colon Cancer
Presenter Josiane Therrien
Citation Annals of Oncology (2014) 25 (suppl_2): ii14-ii104. 10.1093/annonc/mdu165
Authors J. Therrien, L. Guay, M. Dupuis, M. Sene
  • Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke/CA

Abstract

Introduction

The aim of this study was to review our local experience with diagnosis, staging and treatment of stage II and III colon cancer, particularly regarding the timing and regimens of chemotherapy.

Methods

At Centre Hospitalier Universitaire de Sherbrooke, all patients operated for a non-metastatic colon cancer between 2005 and 2012 and identified as pathological stage II or III according to the AJCC classification 7th version were included in the study. Retrospective analyses were performed on the diagnostic methods, pathology results and adjuvant chemotherapy. Disease free survival (DFS) and overall survival (OS) were examined with Kaplan-Meier plots.

Results

A total of four hundred and one (n = 401) patients were identified with pathological stage II and III cancer. The population was composed of 50,6% of men with a mean age of 71 years. Clinical staging which included colonoscopy, thoracic, abdominal, TEP scans and preoperative CEA were performed in 87,8%, 53,6%, 92,5%, 20,4% and 87,5% of patients respectively. A minority of patients (18,5%) with a stage II tumor received adjuvant chemotherapy compared to 58,2% of patients with stage III disease. An oxaliplatin-based chemotherapy was used for 20 patients (54,1%) with stage II disease and 77 patients (65,8%) with stage III. There were no benefits in the five-year OS (80.5 vs 76.9%, p= 0.31) or DFS (81.1% vs 72.2%, p = 0.27) among stage II patients receiving adjuvant therapy compared with surgery alone. Among stage II patients, there was no difference either in the group receiving an oxaliplatin-based chemotherapy or in the group receiving 5FU or capecitabine alone. On the other hand, there was a clear benefit in the five-year OS (69,3% vs 42,7%, p < 0,01) and DFS (61,4% vs 35,4%, p < 0,01) in stage III patients who received adjuvant chemotherapy. A recurrence of disease was found in 58 patients (28,9%) with stage III disease with a trend in favor of chemotherapy (24,8% vs 34,5%, p = 0,13) while it was found in 10% of stage II patients, without a difference between surgery alone or adjuvant therapy (9,8% vs 10,8%, p = 0,5). The median delay between surgery and the oncology consultation was 52(8;343) days while the delay between surgery and the first chemotherapy treatment was 56(14;148) days. There was a trend in the five-year OS (80,7% vs 70,2%, p = 0,19) and DFS (74,8% vs 64,2%, p = 0,13) in the group of patients who received the first adjuvant treatment in less than 6 weeks after surgery. The benefit of chemotherapy was lost if initiated more than 8 weeks after surgery. In addition to the timing of chemotherapy, multivariated analyses showed that T4 tumors, poorly differentiated tumors and lymphovascular invasion were features associated with poorer overall survival.

Conclusion

Our local experience shows that minimizing the interval between surgery and initiation of chemotherapy, a practice that we will adopt, could possibly improve DFS and OS in stage II and III patients. The oxaliplatin-based chemotherapy in stage II patients did not modify DFS and OS. Obviously, the applicability of these results is limited by the fact that this is a retrospective study with a limited number of patients.