Comparison of Three Adjuvant Chemotherapy Regimes using an Extended Log-logistic Model in Women with Operable Breast Cancer

Objective: The main objective of the present study was to compare the effects of three common chemotherapy regimes in terms of disease-free survival (DFS) of breast cancer (BC) patients; the three explored regimes were taxane-based, anthracycline-based and CMF (cyclophosphamide methotrexate and 5-fluorouracil). Materials and methods: In this historical-cohort study, we obtained the information of 62 patients with confirmed BC in non-metastatic stage and followed them for 8 years. All the patients had undergone modified radical mastectomy surgery and had received adjuvant chemotherapy in three medical centers in Tehran, Iran. DFS was considered as 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 and the probability of 5-years DFS was 0.48. Survival analysis indicated that the type of chemotherapy (OR(CMF vs. taxane) = 0.33, OR(anthracycline vs. taxane) = 0.74), grade (OR(III vs. I or II) = 0.35), tumor size (OR(>5cm vs. <5cm)= 0.179) and nodal involvements (OR(Yes vs. No)= 0.36) affected DFS. Conclusion: The current study revealed that the efficacy of taxane-based, in terms of DFS, was more than CMF (p = 0.05). Moreover, taxane-based chemotherapy 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 lymph nodes in lengthening DFS, it is crucial to highlight the role of public education and screening programs in order to detect tumor in its early stages.