Predictive Factors for Positive Margin and the Surgical Learning Curve in Non-Palpable Breast Cancer After Wire-Guided Localization - Prospective Study of 214 Consecutive Patients.

To investigate the most commonly used technique, the wire-guided localization (WGL) in non-palpable breast cancer. To analyze the effective factors on positive surgical margins in our practice and determine the surgical learning curve of this method. Prospective consecutive study was performed from January 2005 to December 2011. Inclusion criteria was a non-palpable breast lesion with malignancy on preoperative histology. All lesions were localized by ultrasound or stereotactic guided wire placement. Margins 1 mm or closer were accepted as positive margins which required re-excision. To determine the learning curve of WGL method we investigated the change in the reoperation rate after primary procedure performed by "high-volume" surgeon. Two hundred and fourteen consecutive patients were enrolled. In 23 patients (10.7%) reexcision was needed. Positive surgical margins were significantly influenced by the patient's age (p = 0.03), tumor volume (p < =0.001), proportion of tumor volume/specimen volume (p < 0.001), presence of DCIS (p < 0.001), multifocality (p = 0.03) and the learning curve (p = 0.006) with univariate analysis. Only the tumor volume, presence of DCIS and the learning curve were proved as independent prognostic factor for reoperation by multivariate analysis. The reoperation rate decreased below 20% after the fortieth operation. Results of our single institutional study suggest, that this localization technique can be performed safely with very good results after 40 procedures as a learning curve for surgeons.