The Prognostic Value of STAT1 Overexpression and Clinicopathologic Features in Breast Cancer Patients Receiving Adjuvant Radiotherapy
Wen-Chung Chen, Cheng-Lin Wu, Yu-Hsuan Lai, Hung-Yu Chen, Helen HW Chen. National Cheng Kung University Medical College and Hospital, Tainan, Taiwan
Background: Adjuvant radiotherapy is a key component of breast cancer management, significantly reducing the risk of locoregional relapse (LRR) and improving overall survival. The aim of this study was to evaluate our institutional experience of radiotherapy in patients with operable primary breast cancer and study the prognostic value of signal transducer and activator of transcription 1 (STAT1) and clinicopathologic features on LRR.
Design: We retrospectively reviewed 1623 consecutive patients with operable breast cancers which received complete course of adjuvant radiotherapy at our institution between 1988 and 2009. Clinicopathologic and outcome parameters were analyzed. Kaplan-Meier product limit method was used to calculate loco-regional recurrence-free survival (LRFS). Cox proportional hazards models were performed to assess the prognostic significance of these clinicopathologic parameters on LRFS. Immunohistochemical study of STAT1 on 61 formalin-fixed, paraffin-embedded primary tumors from patients with LRR and a cohort of 145 consecutive patients who had no evidence of disease for at least 10 years were performed. The prognostic value of STAT1 on LRR was also evaluated.
Results: With a median follow-up of 6.1 years, a total of 83 (5.1%) patients developed LRR in 4.8 months to 12.5 years (median, 2.0 years). There was a higher rate of LRR for patients with triple-negative (TN) or HER2-positive tumors than those with hormone receptor (Rec)+/HER2- tumors. The 10-year LRR for TN, Rec-/HER2+, and Rec+/HER2+ were 8.5%, 14.2% and 7.6%, respectively, while the 10-year LRR for Rec+/HER2- was 3.9% (P < 0.01). Multivariate analyses showed that patients with advanced T stage, nodes positive, HER2 positive or TN tumors had shorter LRFS (all P < 0.05). In 206 patients with immunohistochemical studies, STAT1 overexpression was correlated with shorter LRFS (p = 0.02) and was an independent predictor of LRR after radiotherapy (p < 0.001).
Conclusions: Patients with TN or HER2-positive breast cancer had a greater risk of LRR after adjuvant radiotherapy. STAT1 overexpression identified a subset of patients with a significantly higher risk of LRR.
Wednesday, March 6, 2013 1:00 PM
Poster Session VI # 15, Wednesday Afternoon