Comparison of Three Adjuvant Chemotherapy Regimes usingan Extended Log-logistic Model in Women with OperableBreast Cancer

Objective: The main objective of the present study was to compare the effects of three common chemotherapyregimes in terms of disease-free survival (DFS) of breast cancer (BC) patients; the three explored regimes weretaxane-based, anthracycline-based and CMF (cyclophosphamide methotrexate and 5-fluorouracil). Materialsand methods: In this historical-cohort study, we obtained the information of 62 patients with confirmed BC innon-metastatic stage and followed them for 8 years. All the patients had undergone modified radical mastectomysurgery and had received adjuvant chemotherapy in three medical centers in Tehran, Iran. DFS was consideredas the end-point. Afterwards, an extended log-logistic regression model was used to compare these regimes.
Results: The mean (SD) age of patients was 49.0 (10.3) years. The median time of follow-up was 20.0 months andthe probability of 5-years DFS was 0.48. Survival analysis indicated that the type of chemotherapy (OR(CMFvs. taxane) = 0.33, OR(anthracycline vs. taxane) = 0.74), grade (OR(III vs. I or II) = 0.35), tumor size (OR(>5cmvs. <5cm)= 0.179) and nodal involvements (OR(Yes vs. No)= 0.36) affected DFS.
Conclusion: The current studyrevealed that the efficacy of taxane-based, in terms of DFS, was more than CMF (p = 0.05). Moreover, taxane-basedchemotherapy prolonged DFS more than anthracycline-based one although the difference was not significant(p= 0.63). Finally, considering the importance of tumor size, histological grade and number of involved lymphnodes in lengthening DFS, it is crucial to highlight the role of public education and screening programs in orderto detect tumor in its early stages.