BACKGROUND: The currently available chemotherapeutic regimens do not use a specifically designed drug delivery system. The objective of this study was to compare outcome measures, adverse effects, and cost of FOLFOX4 and FOLFIRINOX treatments in rectal cancer patients.

MATERIAL AND METHODS: We enrolled patients who, after surgery, did not undergo chemotherapy or radiotherapy (Control group); were administered 200 mg/m² folinic acid, 400 mg/m² fluorouracil, and 85 mg/m² oxaliplatin (FFO group); or were administered 400 mg/m² folinic acid, 400 mg/m² fluorouracil, 180 mg/m² irinotecan, and 85 mg/m2 oxaliplatin (FFIO group). We recorded tumor and nodal staging, carbohydrate antigen 19-9, serum carcinoembryonic antigen, total cost of treatment, disease recurrence, overall survival, and adverse effects. We used the 2-tailed paired t test following Turkey post hoc test for adverse effects, recurrence analysis, and cost of treatment at 95% of confidence level.

RESULTS: Surgery (p=0.00089), FOLFOX4 (p=0.000167), and FOLFIRINOX (p=0.00013) improved disease-free conditions. Only surgery failed to maintain carbohydrate antigen and carcinoembryonic antigen 19-9 levels. The cost of chemotherapeutic treatments was in the order of FFIO group > FFO group > Control group. Non-fatal treatment-emergent adverse effects were due to chemotherapeutic drugs. However, fatal chemotherapeutic treatment-emergent adverse effects were observed only in the FFIO group. Overall survival, irrespective of cancerous condition, was higher in the FFO group.

CONCLUSIONS: FOLFIRINOX had less total cancer recurrence than FOLFOX4. However, FOLFIRINOX had more fatal treatment-emergent adverse effects and excessive cost of treatment than FOLFOX4 regimen.

Keywords: Antigens, Tumor-Associated, Carbohydrate, Carcinoembryonic Antigen, Rectal Neoplasms