İçli F.Altundağ K.Akbulut H.Paydaş S.Başaran G.Saip P.Doğu G.G.Eralp Y.Uslu R.Sevinç A.Onur H.Mandel N.M.Sezgin C.Altınbaş M.Güler N.Işıkdoğan A.Gökmen E.Uygun K.Üstüner Z.Yaren A.Demirkan B.Coşkun U.Ata A.Özkan M.Arican A.2019-10-262019-10-2620151340-6868https://doi.org/10.1007/s12282-013-0506-yhttps://hdl.handle.net/11454/16874Background: Optimal duration of adjuvant trastuzumab in early breast cancer is an unresolved issue. In this observational study, we compared the outcome of 9 weeks and 1 year adjuvant trastuzumab in early breast cancer patients in Turkey. Methods: Records of 680 patients with HER2-positive early breast cancer who received adjuvant trastuzumab plus chemotherapy were obtained and patients were followed up to compare the disease-free survival (DFS) outcome of 9 weeks versus 1 year trastuzumab. Results: Nine weeks and 1 year trastuzumab was given to 202 (29.7 %) and 478 (70.3 %) patients, respectively. There was a significantly lower rate of patients with negative lymph nodes in the 9-week trastuzumab group. At median 3 years of follow-up from the date of starting trastuzumab, the DFS rates were 88.6 and 85.6 %, respectively (p = 0.670). When adjusted for all the prognostic factors that were significant on univariate analysis, again there was no significant difference in DFS between the groups (HR 0.675; 95 % CI 0.370–1.231; p = 0.200). Cardiac toxicity defined as a ?15 % decrease in LVEF was significantly higher in the 1-year trastuzumab group (1.88 % versus none for 1-year and 9-week trastuzumab groups, respectively; p = 0.050). Conclusion: The results of this observational study suggest that DFS outcome of 9 weeks of adjuvant trastuzumab may be comparable to 1 year adjuvant trastuzumab: this needs confirmation by randomized trials. © 2013, The Japanese Breast Cancer Society.en10.1007/s12282-013-0506-yinfo:eu-repo/semantics/closedAccessAdjuvant treatmentCardiotoxicityEarly breast cancerNine weeks trastuzumabArticle22548048524338610Q1