Effect on patient outcome of residual DCIS in patients with complete eradication of invasive breast cancer after neoadjuvant chemotherapy

Abstract

530 Background: To determine whether residual ductal carcinoma in situ (DCIS) after completion of preoperative chemotherapy affects the outcome of patients with hiostologically defined complete eradication of invasive cancer. Methods: Retrospective analysis of a database including 2,302 breast cancer patients treated prospectively with neoadjuvant chemotherapy at the UT MD Anderson Cancer Center between 1980 and 2004 was performed. The overall, disease-free and local recurrence-free survivals were compared for patients with no residual invasive or in situ cancer (pCR) and those with no residual invasive cancer but persistent in situ disease (pCR+DCIS). Results: The mean follow-up was 250 months. Of the 2,302 treated patients 78 (3.4%) had pCR, 199 (8.6%) had pCR+DCIS, and 2025 (88%) had residual invasive cancer. The 5-year (87.1% in both) and 10-year (81.3% vs 81.7%) disease-free survival rates were similar for cases with pCR and pCR+DCIS. The 5-year (91.9% vs. 92.5%) and 10-year (91.8% vs. 92.5%) overall survival rates were also similar and significantly better than the rate of patients with residual invasive cancer (74.4%, p<0.001). The 5-year local-regional recurrence-free survival rates were also not different for patients with pCR (92.8%, 95% CI: 86.1%-96.4%) and those with pCR+DCIS (90.9%, 95% CI: 77.3%- 96.5%), p=0.63. Conclusions: Residual DCIS in patients who experience complete eradication of the invasive cancer in the breast and lymph nodes does not adversely affect survival or local recurrence rate. Inclusion of cases with residual DCIS in the definition of pathologic complete response is justified when this outcome is used as early surrogate for long term-survival. No significant financial relationships to disclose.