Outcome at 8 years after breast-conserving surgery and radiation therapy for invasive breast cancer: Influence of margin status and systemic therapy on local recurrence

Purpose: To examine the relationship between pathologic margin status and o utcome at 8 years after breast-conserving surgery and radiation therapy, Patients and Methods: The study population comprised 533 patients with inte rnational Union Against Cancer/American Joint Committee on Cancer clinical stage I or II breast cancer who had assessable margins, who received at lea st 60 Gy to the primary tumor bed, and who had more than 8 years of potenti al follow-up. Each margin was scored (according to the presence of inversiv e or in situ disease that touched the inked surgical margin) as one of the following: negative, close, focally positive, or extensively positive. Outc ome at 8 years was calculated using crude rates of first site of failure. A polychotomous logistic regression analysis was performed, Median follow-vp time was 127 months. Results: At 8 years, patients with close margins and those with negative ma rgins both held a rate of local recurrence (LR) of: 7%, patients with exten sively positive margins had an LR rate of 27%, whereas patients with focall y positive margins had an intermediate rate of LR of 14%, In the polychotom ous logistic regression model, margin status and the use of systemic therap y were the only two variables that had significant effects on the risk rati o of LR to remaining alive and free of disease, Among the 45 patients with focally positive margins who received systemic therapy, the crude LR rate w as 7% at 8 years (95% confidence interval, 1% to 20%), Conclusion: Pathologic margin status and the use of adjuvant systemic thera py are the most important factors associated with LR among patients treated with breast-conserving surgery and radiation therapy. J Clin Oncol 88:1668-1675, (C) 2000 by American Society of Clinical Oncolog y.