Impact of administration-related factors on outcome of adjuvant chemotherapy for primary breast cancer.

The survival of 229 patients treated with adjuvant i.v. cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) after surgery for primary breast cancer was analyzed according to three administration-related factors: total number of cycles received, time elapsed between surgery and start of chemotherapy, and dose intensity of treatment. All parameters were found to be significantly associated with survival of patients in a univariate analysis. Multivariate analysis confirmed the independent prognostic importance of dose intensity and time between surgery and chemotherapy. Although prospective studies are needed to confirm such results, clinicians should be aware that unnecessary treatment delays or dose reductions in adjuvant chemotherapy for breast cancer are probably detrimental to patient survival.