Adjuvant Chemotherapy of Early Stage Breast Cancer in Community-based Cancer Treatment Fields: CMF Compared with Anthracycline/Taxane-based Regimens

Background: The mortality rate from breast cancer has declined in recent years. The combination of cyclophosphamide, methotrexate, and 5-fluorouracil, as a pioneer adjuvant chemotherapy for breast cancer, followed by the introduction of anthracycline/taxane-based regimens have resulted in favorable outcomes for early-stage breast cancer. The current study aimed to compare breast cancer treatment outcomes between the cyclophosphamide, methotrexate, and 5-fluorouracil and anthracycline/taxane-based regimens. Methods: In this cohort study, we extracted medical records of 1098 breast cancer patients who referred to oncology centers affiliated with Mashhad University of Medical Sciences from 1991 to 2011. We included patients with Stages I and II invasive cancers who were candidates for systemic chemotherapy. Patients were divided into the cyclophosphamide, methotrexate, and 5-fluorouracil or anthracycline/taxane-based arms. We considered median event-free survival, median overall survival, 5- and 10-year event-free survival, and 5- and 10-year overall survival as the study endpoints. Results: The cyclophosphamide, methotrexate, and 5-fluorouracil arm had a median event-free survival of 190 months, with a 5-year event-free survival of 77% and 10-year event-free survival of 61%. The anthracycline/taxane arm had a median event-free survival of 212 months, a 5-year event-free survival of 74%, and a 10-year event-free survival of < 61%. There were no significant differences between the two arms (P=0.3). The cyclophosphamide, methotrexate, and 5-fluorouracil arm had a 5- year overall survival of 87% and a 10-year overall survival of 76%, whereas the anthracycline/taxane-based arm had a 5-year overall survival of 83% and 10-year overall survival of < 76% (P=0.2). Stage and estrogen receptor status significantly affected outcome in univariate analysis; however, the only important prognostic factor in multivariate analysis was disease stage. Conclusion: Similar effectiveness exists between cyclophosphamide, methotrexate, and 5-fluorouracil and anthracycline/taxane-based regimens in terms of adjuvant treatment outcome for early-stage breast cancer. We can be confident that cyclophosphamide, methotrexate, and 5-fluorouracil is more favorable due to the infrequent adverse effects.