Stricter adherence to chemotherapy drug dosage recommendations improve survival outcomes in stage 3 colon cancer patients

This study investigated the effect of chemotherapy drug dose on the survival outcomes of stage 3 colon cancer patients. 

Relative dose intensity (RDI) refers to the proportion of the standard drug dose received during chemotherapy. Previous studies have shown that an RDI greater than 70% is associated with better survival outcomes. This remains to be confirmed in stage 3 colon cancer patients taking oxaliplatin (Eloxatin). Dosage recommendations are often not met among patients due to the toxicity of the drugs and the resulting side effects.

This study investigated whether RDI was associated with survival rates in stage 3 colon cancer patients. 367 patients took part. Patients were grouped by treatment. 126 patients received 5-FU/LV:  5-fluorouracil (Oncofluor, Fluorblastin) and leucovorin (Wellcovorin). 152 patients received 5-FU/LV plus oxaliplatin (Eloxatin), or 5-FU/LV/Ox. 30 patients received oxaliplatin and capecitabine (Xeloda), or Ox/C. 48 patients received capecitabine alone. Patients received chemotherapy for an average of 5.4 months and were followed for 5 years post-chemotherapy to monitor survival.

Patients taking 5-FU/LV/Ox had a higher overall survival rate after 5 years (69.5%) than patients taking 5-FU/LV (54%). Similarly, 69.6% of 5-FU/LV/Ox patients survived for 3 years without disease, in comparison to 56.6% of 5-FU/LV patients.

The survival rates of patients 5 years after chemotherapy were higher in patients who achieved an RDI of greater than 70% (66.3%), than those who did not (50.5%). Similarly, the disease-free survival rates of patients 3 years after chemotherapy were higher in patients who had achieved an RDI of greater than 70% (66.1%) than those who did not (52.7%).

71.4% of patients taking 5-FU/LV/Ox achieved an RDI greater than 70%. In comparison, 40% of patients taking Ox/C and 30.4% of patients taking capecitabine alone achieved an RDI greater than 70%.

Patients over the age of 75 had 2 times the risk of a shorter survival time. Patients whose tumors had spread through the walls of the colon had 5.88 times the risk of a shorter survival time. 

The authors concluded that an RDI greater than 70% improves survival rates in stage 3 colon cancer patients. 

More men than women were included in the study. The results could be more applicable to men. 

Consult your doctor to discuss the dosage of your chemotherapeutic drugs.