Abstract P6-09-01: Predictors of locoregional recurrence after neoadjuvant chemotherapy and surgery for node positive breast cancer: Results from ACOSOG Z1071 (Alliance)
Abstract Background: Locoregional recurrence (LRR) is a concern after neoadjuvant chemotherapy. Absolute risk of LRR and risk factors associated with LRR among women with node positive breast cancer treated with neoadjuvant chemotherapy on ACOSOG Z1071 were examined. Methods: ACOSOG Z1071 (Alliance for Clinical Trials in Oncology) enrolled cT1-3, N1-2 breast cancer patients treated with neoadjuvant chemotherapy from 2009-2011. All patients underwent axillary dissection. Data was analyzed for locoregional recurrence-free survival (LR-RFS) and multivariable analysis performed to identify factors impacting locoregional recurrence. Results: Of 756 women enrolled, 701 patients were eligible. Median follow-up was 4.0 years (range 0.03–6.2). 39 pts (5.6%) experienced LRR (32 LRR alone and 7 LRR concurrent with metastatic disease) and 96 patients (13.7%) died. LR-RFS was lowest in patients with triple negative tumors (TNBC) (87.6% at 3 years), followed by HER2-positive tumors (94.1%) compared with Hormone Receptor (HR) positive/HER2-negative tumors (96.9%). Residual in-breast disease was present in 57% of patients undergoing BCT and 73% of patients undergoing mastectomy (p<0.0001). LRR was higher in BCT compared to mastectomy (p=0.018), however when evaluated by subtype there was no significant difference in LRR by BCT vs mastectomy. There was no difference in LRR by clinical T stage at presentation or pathologic N stage, however LRR increased with higher pathologic T stage (p=0.006). Overall LRR was lower in patients who achieved a pathologic complete response (pCR) across all tumor subtypes (0% in HR positive/HER2-negative, 2.1% in TNBC, 4% in HER2-positive at 3 years) than in non-pCR patients (HR=0.37, p=0.04). By tumor subtype, pCR was associated with a lower LRR in patients with TNBC (HR=0.17, p=0.019), but was not significantly different by pCR in HER2-positive (HR=0.50, p=0.31) or HR-positive/HER2-negative tumors (HR=inestimable). In the multivariable model, factors associated with increased LRR risk were tumor subtype (TNBC and HER2-positive tumors, p<0.0001), lack of pCR in the breast (p=0.013), breast conservation surgery (p=0.018) and omission of adjuvant radiation therapy (p=0.010). Predictors of locoregional recurrence UnivariableMultivariableVariableHR (95% CI)p-valueHR (95% CI)p-valueClinical T stageT0-T2REF0.34REF0.087T3-T41.38 (0.72-2.65) 1.87 (0.91-3.84) Tumor BiologyHR+/Her2-REF0.002REF<0.0001Her2+1.49 (0.65-3.45) 2.11 (0.89-5.00) Triple negative3.59 (1.68-7.68) 5.53 (2.53-12.13) Path CR breastNoREF0.019REF0.013Yes0.35 (0.15-0.84) 0.27 (0.09-0.76) Path CR breastNoREF0.064REF0.81Yes0.51 (0.25-1.04) 0.67 (0.29-1.59) SurgeryBCTREF0.067REF0.018Mastectomy0.55 (0.29-1.04) 0.43 (0.22-0.87) RadiationYesREF0.033REF0.010No2.18 (1.06-4.48) 2.60 (1.26-5.39) Conclusion: In patients with node-positive breast cancer treated with neoadjuvant chemotherapy, early LRR is higher in TNBC and HER2-positive tumors. In TNBC patients pCR is associated with lower LRR than residual disease. In this contemporary cohort of node-positive, HER2-positive tumors treated with anti-HER2 therapy, patients achieving a pCR had low LRR rate. Adjuvant radiation appears to be important for locoregional control regardless of pCR. Citation Format: Boughey JC, Ballman KV, McCall LM, Mittendorf EA, Hunt KK. Predictors of locoregional recurrence after neoadjuvant chemotherapy and surgery for node positive breast cancer: Results from ACOSOG Z1071 (Alliance) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-09-01.
Abstract P1-01-06: Evaluation of the stage IB designation of the 7th edition of the AJCC staging system: Biologic factors are more important
Abstract Purpose: The stage IB designation was added to the AJCC 7th edition staging system to denote micrometastasis in patients with T1 tumors. We have previously examined this group and found that receptor status and nuclear grade were better survival discriminates than the presence of micrometastases. The current study was undertaken to validate this finding in a larger cohort from the American College of Surgeons Oncology Group (ACOSOG) Z0010 study. Methods: Clinicopathologic and outcomes data from patients enrolled on ACOSOG Z0010 were recorded. All patients underwent breast conserving surgery, sentinel lymph node biopsy and whole breast radiation for clinical T1-2, N0 breast cancer. Sentinel lymph nodes were evaluated by H&E locally and if negative, by immunohistochemistry (IHC) at a central laboratory. Patients were staged according to the 7th edition AJCC system and recurrence-free (RFS), disease-specific (DSS) and overall survival (OS) were determined using the Kaplan-Meier method and compared using the log-rank test. Results: There were 5210 eligible and evaluable patients enrolled on ACOSOG Z0010. AJCC stage distribution was known in 4590 and included: 2849 (62.0%) stage IA, 376 (8.2%) stage IB, 878 (19.1%) stage IIA, 322 (7.0%) stage IIB, and 170 (3.7%) stage III. Median follow-up for the cohort was 9.0 years (range 0–12.6). Five and 10-year RFS, DSS and OS rates for patients with stage IA versus IB disease are shown in table 1. There were no significant differences between groups. When all stage I patients (stage IA and IB) were evaluated by ER status (positive vs negative) or grade (grade 1 vs 2 vs 3), these biologic factors were able to significantly discriminate patients with respect to RFS, DSS and OS (table 2). Conclusion: Differentiating patients with micrometastases (stage IB) from node negative patients (stage IA) does not stratify patients well with respect to survival. Biologic factors including ER status and grade are better discriminants of survival than the presence of small volume nodal metastases in patients with early stage breast cancer. Breast cancer staging should include biologic factors from the primary tumor. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-06.