Prognostic significance of dose intensity and haematological toxicity in breast cancer patients administered with adjuvant CMF chemotherapy

Abstract

Introduction. The aim of the study was to assess the prognostic significance of selected clinical factors, including dose intensity and haematological toxicity in breast cancer patients administered with adjuvant CMF chemotherapy.

Material and methods. The study group were 264 patients who received 6 CMF cycles between 1990 and 1997. The CMF regimen consisted of cyclophosphamide 100 mg/m² p.o. on days 1–14, methotrexate 40 mg/m² i.v. on days 1 and 8, and 5-fluorouracil 600 mg/m² i.v. on days 1 and 8, every four weeks, for a total of six cycles.

Results. Median follow-up was 7.7 years (range 4.0–11.6 years). The dose intensity of administered cyclophosphamide, methotrexate and 5-fluorouracil relative to the planned dose intensity was calculated for each patient. Median average relative dose intensity for all drugs was 86% (83%, 77% and 93% for cyclophosphamide, methotrexateand 5-fluorouracil, respectively). Actuarial survival probability at 5 and 10 years was 76% and 62%, and disease freesurvival probability 69% and 59%. Using multivariate analysis the number of involved lymph nodes and relative doseintensity were the only significant prognostic factors. A value of 78% or more was associated with longer overall survival (hazard ratio 0.6; p = 0.045) and time to relapse (hazard ratio 0.57; p < 0.001).

Conclusion. Relative dose intensity of 78% or more was associated with longer overall survival and time to relapse. Decreased values of white blood cells, erythrocytes, haemoglobin and platelets did not carry prognostic information.