Comparision of activity and toxicity of 9- and 52- week trastuzumab treatment in patients with HER2 positive early stage breast cancer

Introduction: Human epidermal growth factor receptor 2 (HER 2) related to poor prognosis is positive in 15- 20% of breast cancers. Activity of trastuzumab was proven in treatment of early and advanced stage of breast cancer. It is not clear how long trastuzumab will be continued in adjuvant treatment of early breast cancer (EBC). In this retrospectiv study we compared the activity and the toxicity of 9-and 52- week trastuzumab therapies in adjuvant setting in EBC.Materials and methods: We evaluated 184 female patients who received trastuzumab in adjuvant treatment of EBC between 16th August 2006 and 31st December.2010 in Gazi University Faculty of Medicine, Department of Medical Oncology retrospectively. Nine and 52 weeks trastuzumab groups had 88 and 96 patients respectively. ?SPSS 15 for Windows Evaluation Version? was used for statistical analysis.Findings: After 27.82 (6.6- 61.7) months follow up, 7 (8%) recurrences and 2 (2.3%) deaths in the 9 weeks group and 7 (7.39%) recurrences and 1 (1%) death in the 52 weeks group were observed. Thirty six- month disease free survival (DFS) rates were 89% and 88% in the 9 and 52 weeks groups respectively (P= 0,812). Overall survival (OS) rates were 98% in both groups (P= 0.813). No statistical significant differences were determined between groups Cardiotoxicity occured in 2 (2.8%) patients in the 52 weeks group and was not identified in the 9 weeks group.Conclusion: Activities of 9 and 52 weeks trastuzumab in treatment of EBC are similar. In 52 weeks group cardiotoxicity is more common.Key Words: Trastuzumab, early stage breast cancer, adjuvant.