P5-14-19: Ipsilateral Breast Tumor Recurrence Prediction with Web-Based Normogram in Korea.

Abstract

Abstract Purpose Ipsilateral Breast Tumor Recurrence(IBTR!) 2.0 is web-based tool which predict the ten years risk of local recurrence after breast conserving theraphy. This tool integrates seven prognostic factors (patient age, margin status, lymphovascular invasion, tumor size, tumor grade, use of chemotherapy and hormonal therapy) for local recurrence with or without radiation theraphy. To validate IBTR! 2.0 for Korean breast cancer patients, Samsung Medical Center database was used between 1994 and 2001. Methods The IBTR! 2.0 nomogram was tested against 358 patients who underwent breast conserving surgery with radiation theraphy from Samsung Medical Center between 1994 and 2001. The individual dadabase which was entered into IBTR! 2.0 computer model generate predictive local recurrence rate. The mean predicted and observed 10-year estimates were compared for the entire cohort and for four groups predefined by nomogram-predicted risks: group 1: less than 3%; group 2: 3% to 5%; group 3: 5% to 10%; and group 4: more than 10%. Results IBTR! version 2.0 predicted an overall 10-year IBTR estimate of 5.5% (95% CI, 5.2 to 5.9), while the observed estimate was 7.69% (20 IBTR cases in 358 patients, 95% CI, 1.6 to 9.3; P=0.59). The predicted and observed IBTR estimates were: group 1 ( 2 cases in 67 patients): 2.3% versus 2.9%, P=0.53; group 2 (2 cases in 124 patients)): 3.9% versus 4.1%, P=0.18; group 3 (14 cases in 139 patinets): 7.3% versus 4.8%, P=0.13; and group 4 (2 cases in 28 patients): 12.15% versus 7.1%, P=0.61. Conclusion IBTR! 2.0 is acceptable nomogram for predicting 10 years local recurrence using Samsung medical Center database. This nomogram showed overestimation in group 3, 4, however did not showed statistical differences. This nomogram may assist patient counseling and medical decision making, but prior to using whole Korean patients, this model requires validation with multiple Korean sources.