Quality of adjuvant CMF chemotherapy for node-positive primary breast cancer: a population-based study

Purpose: Adjuvant 'classical' oral cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) has long been the mainstay of adjuvant chemotherapy for premenopausal breast cancer patients. The Comprehensive Cancer Center North Netherlands (CCCN) breast cancer working group performed a retrospective audit of treatment guideline adherence and quality of CMF in hospitals in the CCCN area. Methods: The CMF treatment data of 251 consecutive axillary lymph node-positive breast cancer patients <50 years old, diagnosed between 1993 and 1996, were analyzed. Results: Ninety-four patients (42%) completed adjuvant CMF without dose adjustment or delay. Overall median relative dose intensity (RDI) was 92.6 (IQR 85.5-97.7). Sixty patients (24%) had an RDI <85, and 7% had an RDI <65. Myelotoxicity was the main reason for reductions and delays. Of 176 irradiated patients, 96% received radiotherapy simultaneously with CMF. Median CMF dose intensity nor median duration differed between patients who underwent mastectomy, mastectomy and radiotherapy, or breast-conserving therapy. Radiotherapy did not influence the median RDI (94 without versus 92 with radiotherapy). G-CSF, administered at least once to 76 patients, did not result in a higher median RDI. Median RDI was slightly higher when >3 patients/year (P=0.014) were treated by one specialist or >10 patients classified for adjuvant chemotherapy yearly in a hospital (P=0.037). Conclusion: The adherence to CMF treatment guidelines was generally good. Simultaneous radiotherapy did not affect the median RDI of CMF. G-CSF had no impact on the median RDI but patient volume did influence the RDI.