The effect of adjuvant chemotherapy initiation time on survival in colorectal cancer

Studies of adjuvant chemotherapy initiation time in colorectal cancer have shown that chemotherapy should be started within eight weeks at the latest after surgical resection. Many studies have found that delay in initiating adjuvant therapy generally results in worse disease-free and overall survival. The aim of our study is to evaluate the effect of starting adjuvant chemotherapy on survival in patients with colorectal cancer. 244 patients with stage 2 and stage 3 colorectal cancer followed in Akdeniz University Faculty of Medicine were included in the study. ROC analysis was performed for the time to start adjuvant chemotherapy. This time was not found to be significant for the ideal chemotherapy start time. According to literature data, patients; were divided into two groups as early adjuvant chemotherapy (<6 weeks) and late adjuvant chemotherapy (>6 weeks) and analyzed. The number of patients who started treatment in the early period was 174 (71%) and 70 (29%) in the late period. It was observed that the mean progression-free survival time of patients who started adjuvant chemotherapy in the early period (109,28 [95% CI: 98,06-120,51]) was higher than those who were started in the late period (81,98 [95% CI: 66.17-97,80]); but it was not found to be statistically significant (p=0.193). It was observed that the mean overall survival time of patients who were started adjuvant chemotherapy in the early period (112,89 [95% CI: 102,13-123,65]) was higher than those who started in the late period (85.82 [95% CI: 71.34-100,29]); but it was not found to be statistically significant (p= 0.094). In conclusion, the relationship between adjuvant chemotherapy onset time and survival could not be clearly demonstrated in our study. According to literature data, it is recommended to start adjuvant chemotherapy within 8 weeks at the latest. Key Words: Colorectal Cancer, Adjuvant Chemotherapy, Survival