Survival of stage III colon cancer patients with adjuvant chemotherapy: Experience from a specialized cancer institute in Latinoamerica - Peru

204 Background: In Peru, colon cancer is the 5th most common cause of cancer and the sixth most deadly. Currently, surgery remains as the only curative therapy, however, there is risk of recurrence. Adjuvant chemotherapy has become a useful tool to improve progression-free survival (PFS) and overall survival (OS). In this study, we determine the current survival of our stage III colon cancer patients, submitted to adjuvant chemotherapy, and if this is similar to the evidence seen in large international studies; also, we analyze if delay of adjuvant chemotherapy has impact on survival. Methods: This descriptive cross-sectional study involved 162 patients with stage III colon cancer who underwent a resection surgery and received adjuvant fluoropyrimidine-based chemotherapy. They were evaluated, according to the TNM classification (tumor, nodule), as low risk (T1-T3, N1) and high risk (T4, N2). We also classified patients, according to the weeks of delay from surgery to adjuvant chemotherapy, into subgroups of 6, 8 and 10 weeks. Results: The mean age was 63.7 years, 63 patients were women (38.9%), 99 patients (61.1%) were men. Only 38.3% of patients started adjuvant chemotherapy in the first 6 weeks after surgery, and 85.8% of patients, in the first 10 weeks; the median time from surgery to initiation of adjuvant chemotherapy was 7.0 weeks. We estimated that, at 3 years, the median PFS is 73.5% (95% CI: 65.8-82.1). The 3-year PFS in the low-risk group was 82.9% (95% CI: 72.3-95.0) and 67.3% (95% CI: 57.2-79.2) in the high-risk group. It was estimated that at 3 years, the median OS is 81.1% (95% CI: 75.2-87.5). The 3-year OS in the low-risk group was 87.9% (95% CI: 80.4-96.2) and 76.0% (95% CI: 67.8-85.3) in the high-risk group. Conclusions: The PFS and OS in Peruvian population is similar to data evidenced in international historical studies such as the IDEA trial. This study, also, suggests that starting adjuvant treatment within 10 weeks does not present an impact on OS and PFS in our population.