Quality of adjuvant chemotherapy in primary breast cancer in a non-trial setting. A comprehensive cancer centre study. The Breast Cancer Group of the Dutch Comprehensive Cancer Centre East (IKO).

The quality of adjuvant chemotherapy with cyclophosphamide, methotrexate and 5-fluorouracil (CMF) and the compliance with guidelines for this treatment were studied in 323 premenopausal patients with node positive breast cancer, who were treated in the Comprehensive Cancer Centre East of The Netherlands (IKO) from 1988 to 1992, outside the setting of a clinical trial. The interval surgery-chemotherapy, the duration of chemotherapy, dose intensity (DI) and relative dose intensity (RDI) of CMF chemotherapy and validations of dose modifications were evaluated. 295 of 323 patients (91%) received adjuvant chemotherapy. CMF chemotherapy was used in 230 patients (78% of the chemotherapy receiving patients). The median time to the start of chemotherapy was 62 (range-35-139) days after surgery. Forty-two per cent of the patients finished their CMF chemotherapy within 168 days. Two per cent of the patients did not finish the six courses of CMF chemotherapy. The mean DI and RDI of the eligible patients in all CMF using hospitals were 80.4 +/- 28.8% and 78.2 +/- 28.4%, respectively. Aberrations of recommended guideline procedures resulted more often in suboptimal treatment than haematological toxicity. Adherence to the guidelines was variable and resulted in suboptimal adjuvant chemotherapy. The median follow-up of the patients treated in hospitals that agreed to the use of CMF was 5 years. The mean RDI of CMF in the eligible patients who relapsed was 72.2 +/- 32.7%, compared with 81.4 +/- 25.2% for the patients who did not relapse (P 0.01), suggesting a possible influence of the RDI on disease free survival. However, when the patients who did not receive chemotherapy were excluded, the mean RDI of the patients who relapsed was 85.0 +/- 12.6% and of the patients who did not relapse 87.4 +/- 12.6%, which was not significantly different (P = 0.20).