Local-regional recurrence with and without radiation after neoadjuvant chemotherapy and mastectomy for T3N0 breast cancer patients.

Abstract

Abstract Abstract #74 Purpose: The goal of this study was to compare the local-regional recurrence (LRR) risk in patients with clinical T3N0 breast cancer who were treated with neoadjuvant chemotherapy (NeoChemo) and mastectomy (Mastx) according to the use of adjuvant radiation (RT).
 Methods: Clinicopathologic data from 164 patients with clinical T3N0 breast cancer who received NeoChemo and Mastx from 1985 to 2004 were retrospectively reviewed. In this cohort, 121 (74%) patients received adjuvant radiation (RT) while 43 (26%) patients did not. The median number of axillary lymph nodes (LN) dissected was 15. After NeoChemo, 54% of patients (n=89) had no pathologically involved lymph nodes at the time of surgery (ypLN-) while 46% (n=75) had at least 1 lymph node pathologically positive (ypLN+). Actuarial rates were calculated using Kaplan-Meier analysis and compared using log-rank test. Cox proportional hazards models were fit to determine the association of RT with the risk of LRR after adjustment for other patient and disease characteristics.
 Results: At a median follow-up of 77 months, 17 of the 164 patients had a LRR. For all patients, the 5-year local-regional control rates (5-yr LRC) were 90%. The 5-yr LRC for those who received RT (n=121) was 95% and for those who did not received RT (n=43) was 76% (p = 0.002), with a higher proportion of the patients who received RT having pathologically involved LN (+RT 53% vs –RT 23%, p=0.002).
 Among the entire cohort, the 5-yr LRC was 85% for patients with ypLN+ disease and 94% for patients with ypLN- disease (p=0.093). In patients with ypLN+, the 5-yr LRC with no RT (n=11) was 47% and with RT (n=64) was 92% (p<0.001). In patients with ypLN-, the 5-yr LRC with no RT (n=32) was 86% and with RT (n=57) was 98% (p=0.063). Patients who had tumors with high nuclear grade had worse 5-yr LRC (Grade low 100%, intermediate 97%, high 81%, p=0.023). The presence of lymphovascular invasion, close/positive margin, or estrogen receptor status did not statistically correlate with LRC. In a Cox regression model, patients with tumor exhibiting high nuclear grade (Hazard Ratio (HR) 5.0, 95% Confidence Interval (CI) 1.6-15.4), ypLN+ (HR 6.6, 95% CI 2.0-22.1) and no adjuvant RT (HR 7.6, 95% CI 2.4-24.0) had increased risk of LRR.
 Conclusions: Post mastectomy adjuvant RT appears to improve LRC in clinical T3N0 breast cancer patients treated with neoadjuvant chemotherapy and mastectomy. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 74.