327 Impact of Adjuvant Chemotherapy/Radiotherapy on the 5 Year Overall Survival of Patients with Non-Metastatic Rectal Cancer in Bulgaria - a Retrospective Population-Wide Observational Study

Abstract

Abstract Introduction Survival rates of patients with non-metastatic rectal cancer (RC) have increased, due the use of adjuvant chemotherapy/radiotherapy post-surgery, recommended by the National Comprehensive Cancer Network (NCCN) [1–3]. The aim of the study was to analyse the impact of adjuvant chemotherapy/radiotherapy on the 5-year overall survival (OS) of patients diagnosed with non-metastatic RC patients in Bulgaria. Method This is a retrospective population wide observational study of 8968 cases registered with Colorectal cancer in the Bulgarian National Cancer Registry (BNCR) between 2015 and 2016. The mean and median age of patients with left colon (LCC) and right colon (RCC) along with rectal cancer (RC) was analysed. The impact of adjuvant chemotherapy and radiotherapy on the 5-Year OS for non-metastatic RC was analysed. Kaplan-Meier curve with log rank, ANOVA and chi-squared tests were used to estimate the statistical significance. Results The mean age at diagnosis for RCC, LCC and RC was 68.9, 67.41 and 66.4 respectively (p-Value=<0.001). The median age at diagnosis was 69, 68 and 67 for RCC, LCC and RC respectively. Our study showed that patients with non-metastatic RC that received both adjuvant chemotherapy and radiotherapy had a higher 5-year OS compared to patients who received either chemotherapy, radiotherapy or neither therapy (61.4%, 59.5%, 56.2%, 51.8%), p-Value=0.007. Less than 40% of patients received either adjuvant chemotherapy or radiotherapy. Conclusions Adjuvant chemotherapy/radiotherapy improves the 5-Year OS for patients with non-metastatic RC. NCCN guidelines should be implemented in Bulgaria [1–3]. Bulgaria will benefit by implementing an organised screening programme [4].