Significant increased recurrence rates among breast cancer patients with HER2-positive, T1a,bN0M0 tumors.

Abstract

Abstract Abstract #701 Background: Controversy surrounds the prognosis of breast cancer patients with T1a,bN0M0 tumors following locoregional therapy and the need for adjuvant systemic therapy, especially for HER2+ disease. The purposes of the study were to determine the recurrence-free survival (RFS), and distant recurrence-free survival (DRFS) in small HER2+ tumors compared with hormone receptor ( HR)+ and triple receptor- (TN) tumors.
 Methods: Stage T1a,bN0M0 breast cancers diagnosed between 1973-2003 were reviewed by dedicated breast pathologists. HER2+ tumors were defined as 3+ by IHC or gene amplification. Patients were categorized into 3 groups:TN (ER-, PR-and HER2-), HER2+ (regardless of HR status) and HR+ (HER2-). RFS and DRFS were estimated by the Kaplan-Meier method and compared with the log-rank test. Cox proportional hazards models were fit to determine the association of each group with the risk of recurrence after adjustment for other characteristics.
 Results: Of the 1796 patients, 427 were excluded from the analysis due to being male (2), lack of receptor information (249), and adjuvant chemotherapy (176) leaving 1369 pts for analysis. Median age was 57 years,(range, 26-88). There were 381(28%) T1a and 988(72%) T1b tumors; HR+ 68%, TN 23%, HER2+ 9%. Patients who had HER2+ breast cancer tended to be younger,(p=0.001); have more T1a tumors, (p=0.001); and have higher nuclear grade,(p<0.001). At a median follow-up of 74 months(range 1-350), there were 160 recurrences and 77 distant metastases. Five and 10-year RFS and DRFS are summarized in the table. After adjustment for other characteristics, patients with HER2+ breast cancer had a significantly worse RFS (HR: 5.19, 95% CI: 3.21-8.39, p<0.0001) and DRFS (HR: 4.66, 95% CI: 2.47-8.80, p<0.0001) compared to patients with HR-positive breast cancer.
 Conclusions: Breast cancer patients with HER2+ T1a,bN0M0 tumors have a significant risk of relapse and should be considered candidates for adjuvant systemic therapy including anti-HER2 agents.
 
 Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 701.