Mo1072 Optimizing the Utilization of Adjuvant Chemotherapy Following Surgical Resection of Colon Cancer: A Comparison of Laparoscopic Versus Open Approach

Abstract

Purpose Previous research has demonstrated that laparoscopic approach to colon cancer resection is a safe and potentially beneficial alternative to open surgery. Open colon cancer surgery has higher complication rates than laparoscopic surgery, whichmay delay chemotherapy for stage-specific tumors. Omission or delay in chemotherapy is known to significantly impact overall survival. In this study, we examine the use of appropriate adjuvant chemotherapy following open and laparoscopic surgery for colon cancer in a large national cancer registry. Methods The National Cancer Data Base (NCDB) captures over 70% of cancer cases in the United States and provides detailed information on patient, tumor, and treatment characteristics. Cases of colon cancer undergoing segmental or hemicolectomy with node positive disease in the NCDB from 2010-2011 were included in the analysis. Primary outcomes were use of any adjuvant chemotherapy and use of adjuvant chemotherapy within 90 days of surgery. To adjust for non-random treatment selection, propensity adjustment with inverse probability weighting (IPW) was performed. Patient and tumor characteristics before and after IPW adjustment were compared. Weighted logistic regression after IPW was used to compare the association of laparoscopic and open surgery with the use of adjuvant chemotherapy. Results From 2010-2011, 19,531 patients with colon cancer and positive lymph nodes undergoing surgery were identified in the NCDB, with 12,088 patients (61.9%) undergoing open surgery and 7,443 (38.1%) treated laparoscopically. Patients undergoing open surgery tended to have more comorbidities, larger tumors, higher clinical T and N staging, and were more likely to be treated at community cancer programs (as opposed to comprehensive cancer centers or academic research programs); however, these differences were minimized after IPW adjustment (Table). Before IPW, rates of adjuvant chemotherapy use were 62.3% for patients after open surgical resection, compared to 70.6% after laparoscopic surgery (p<0.001). After IPW, odds ratio (OR) for adjuvant chemotherapy use was 1.27 (95% CI: 1.19-1.36) for laparoscopic versus open surgery, indicating that patients undergoing laparoscopic surgery were more likely to receive adjuvant therapy. For adjuvant chemotherapy within 90 days of surgery, OR was 1.28 (1.20-1.36), again favoring a laparoscopic approach (Figure). Conclusion Patients undergoing laparoscopic surgery for pathologic stage III colon cancer had higher rates of adjuvant chemotherapy use and lower rates of delay in chemotherapy initiation compared to those treated with open procedures, likely due to reduced complications from laparoscopic surgery. Further research will need to examine long-term outcomes in this population in order to understand the impact on disease recurrence and long-term survival. Table. Preoperative patient characteristics by surgical approach before and after IPW adjustment