What is the best sequence of chemotherapy in advanced colorectal cancer? Final results of a five-arm study

One hundred and ninety-three patients were assigned to receive 5-FU/LV, irinotecan and oxaliplatin in five different sequential treatment groups: Mayo Clinic Regimen (MCR) + LV5FU2 (group A); MCR + irinotecan (350 mg/m(2)) (group B); MCR + FOLFIRI (group C); MCR + FOLFOX4 (group D); FOLFIRI + FOLFOX4 (group E). The results were as follows: group A (32 patients), median overall survival (OS) 14 months, median time to progression (TTP1) 6 months, median TTP2 5 months, response rate (RR1) 22%, RR2 25%; group B (27 patients), OS 11 months, TTP1 6 months, TTP2 3 months, RR1 22%, RR2 19%; group C (43 patients), OS 14 months, TTP1 5 months, TTP2 5 months, RR1 12%, RR2 19%; group D (45 patients), OS 15 months, TTP1 5 months, TTP2 4 months, RR1 18%, RR2 20%; group E (46 patients), OS 19 months, TTP1 9 months, TTP2 5 months, RR1 39%, RR2 25%. There was a significant difference in OS (p < 0.005) between groups E vs. B and A, D vs. B. Sequential therapy with 3 active drugs (FOLFIRI + FOLFOX4) was the most efficacious combination in comparison with any other two drug combinations applied in our study.