Adjuvant!, Really Optimal for Korean Early Breast Cancer Patients? Validation in a Single Institution in Korea.
Authors: Hwang S. , Lee S. , Jeong J. , Lee H. 
Published: December 2010

Abstract
Purpose: Adjuvant! (www.adjuvantonline.com) is a widely used web-based program that predicts tailored estimates of 10-year mortality and recurrence risks, and the benefit of adjuvant systemic treatment in early breast cancer. But, in Korea, it had not been used routinely yet to decide to choice for adjuvant therapy. Because Adjuvant! was mainly designed with the Surveillance, Epidemiology, and End-Results (SEER) registry in the United States, it is maybe unreasonable that apply to early breast cancer in Korea without proper validation. This study is planned to validate Adjuvant! program with a data of a single institution in Korea.Methods: Using the Gangnam Severance Hospital database, clinical characteristic, pathologic, and treatment data of 272 patients who diagnosed between 1991 and 1998 with stage I, II breast cancer (total 555 patients) were selected with criteria that less than 10-years of follow-up (n=283) was excluded. And they were calculated for predicted 10-year overall survival (OS), breast cancer-specific survival (BCSS), and event-free survival (EFS) for each patient with Adjuvant! (8.0 version). Also the observed outcomes at 10 years were estimated.Results: Among all 272 patients, the differences of 10-year predicted and observed outcomes were 15.8% (78.8-63.0), 12.4% (78.8-66.4), 12.7% (67.8-55.1) for OS, BCSS, EFS, respectively (all P&lt;.05). Almost subgroups had statistically significant differences between predicted and observed values. Only the subgroup that did not treated by the postoperative radiotherapy had not difference (P&gt;.05). The difference (5.1%) of predictive OS values between the 10-years survival group (184 patients) and dead group (88 patients), the difference (-6.4%) of predictive BCSS values between the 10-years breast specific died group (79 patients) and the others (193 patients), and the difference (4.4%) of predictive EFS values between the 10-years event free survivor group (156 patients) and the others (116 patients) had statistically significant, all. Because of the enormous differences between the predictive outcomes by Adjuvant! and the observed outcomes, we had to verify the differences by comparing outcomes with the Cox's proportional hazards model. The 10-years OS, BCSS, EFS derived by the Cox's model were statistically different with the results by Adjuvant! (all P&lt;.05). More powerful with Adjuvant! to predict the survival rate in who had lived, and more with the Cox's model, to estimate the mortality rate in who had died.Conclusion: The predictive 10-years OS, BCSS, EFS by Adjuvant! for patients who had been diagnosed, treated in Gangnam Severance Hospital as early breast cancer had an enormous differences with the observed outcomes. So it would be inappropriate to apply Adjuvant! with Korean early breast cancer patients. However, there was limitations of this study that used relatively small population for validation of Adjuvant! in a single institution. Therefore, the progress of the further validation study with an adequate population in multi-center will be needed.
Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6044.