PURPOSE The Adjuvant Paclitaxel and Trastuzumab trial was designed to address treatment of patients with small human epidermal growth factor receptor 2 (HER2)–positive breast cancer. The primary analysis of the Adjuvant Paclitaxel and Trastuzumab trial demonstrated a 3-year disease-free survival (DFS) of 98.7%. In this planned secondary analysis, we report longer-term outcomes and exploratory results to characterize the biology of small HER2-positive tumors and genetic factors that may predispose to paclitaxel-induced peripheral neuropathy (TIPN). PATIENTS AND METHODS In this phase II study, patients with HER2-positive breast cancer with tumors 3 cm or smaller and negative nodes received paclitaxel (80 mg/m2) with trastuzumab for 12 weeks, followed by trastuzumab for 9 months. The primary end point was DFS. Recurrence-free interval (RFI), breast cancer–specific survival, and overall survival (OS) were also analyzed. In an exploratory analysis, intrinsic subtyping by PAM50 (Prosigna) and calculation of the risk of recurrence score were performed on the nCounter analysis system on archival tissue. Genotyping was performed to investigate TIPN. RESULTS A total of 410 patients were enrolled from October 2007 to September 2010. After a median follow-up of 6.5 years, there were 23 DFS events. The 7-year DFS was 93% (95% CI, 90.4 to 96.2) with four (1.0%) distant recurrences, 7-year OS was 95% (95% CI, 92.4 to 97.7), and 7-year RFI was 97.5% (95% CI, 95.9 to 99.1). PAM50 analyses (n = 278) showed that most tumors were HER2-enriched (66%), followed by luminal B (14%), luminal A (13%), and basal-like (8%). Genotyping (n = 230) identified one single-nucleotide polymorphism, rs3012437, associated with an increased risk of TIPN in patients with grade 2 or greater TIPN (10.4%). CONCLUSION With longer follow-up, adjuvant paclitaxel and trastuzumab is associated with excellent long-term outcomes. Distribution of PAM50 intrinsic subtypes in small HER2-positive tumors is similar to that previously reported for larger tumors.

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Purpose Taxane induced peripheral neuropathy (TIPN) is an important survivorship issue for many cancer patients. Currently, there are no clinically implemented biomarkers to predict which patients might be at increased risk for TIPN. We present a comprehensive approach to identification of genetic variants to predict TIPN. Experimental Design We performed a genome wide association study (GWAS) in 3431 patients from the phase III adjuvant breast cancer trial, ECOG-5103 to compare genotypes with TIPN. We performed candidate validation of top SNPs for TIPN in another phase III adjuvant breast cancer trial, ECOG-1199. Results When evaluating for Grade 3-4 TIPN, 120 SNPs had a p-value <10−4 from patients of European descent (EA) in ECOG-5103. 30 candidate SNPs were subsequently tested in ECOG-1199 and SNP rs3125923 was found to be significantly associated with Grade 3-4 TIPN (p=1.7×10−3; OR=1.8). Race was also a major predictor of TIPN, with patients of African descent (AA) experiencing increased risk of Grade 2-4 TIPN (HR=2.1; p=5.6×10−16) and Grade 3-4 TIPN (HR=2.6; p=1.1×10−11) compared with others. A SNP in FCAMR, rs1856746, had a trend toward an association with Grade 2-4 TIPN in AA patients from the GWAS in ECOG-5103 (OR=5.5; p=1.6×10−7). Conclusion rs3125923 represents a validated SNP to predict Grade 3-4 TIPN. Genetically determined AA race represents the most significant predictor of TIPN.

IMPORTANCE A significant proportion of patients with early-stage triple-negative breast cancer (TNBC) are treated with neoadjuvant chemotherapy. Sequencing of circulating tumor DNA (ctDNA) after surgery, along with enumeration of circulating tumor cells (CTCs), may be used to detect minimal residual disease and assess which patients may experience disease recurrence. OBJECTIVE To determine whether the presence of ctDNA and CTCs after neoadjuvant chemotherapy in patients with early-stage TNBC is independently associated with recurrence and clinical outcomes. DESIGN, SETTING, AND PARTICIPANTSA preplanned secondary analysis was conducted from March 26, 2014, to December 18, 2018, using data from 196 female patients in BRE12-158, a phase 2 multicenter randomized clinical trial that randomized patients with early-stage TNBC who had residual disease after neoadjuvant chemotherapy to receive postneoadjuvant genomically directed therapy vs treatment of physician choice. Patients had blood samples collected for ctDNA and CTCs at time of treatment assignment; ctDNA analysis with survival was performed for 142 patients, and CTC analysis with survival was performed for 123 patients. Median clinical follow-up was 17.2 months (range, 0.3-58.3 months).INTERVENTIONS Circulating tumor DNA was sequenced using the FoundationACT or FoundationOneLiquid Assay, and CTCs were enumerated using an epithelial cell adhesion molecule-based, positive-selection microfluidic device.MAIN OUTCOMES AND MEASURES Primary outcomes were distant disease-free survival (DDFS), disease-free survival (DFS), and overall survival (OS). RESULTS Among 196 female patients (mean [SD] age, 49.6 [11.1] years), detection of ctDNA was significantly associated with inferior DDFS (median DDFS, 32.5 months vs not reached; hazard ratio [HR], 2.99; 95% CI, 1.38-6.48; P = .006). At 24 months, DDFS probability was 56% for ctDNA-positive patients compared with 81% for ctDNA-negative patients. Detection of ctDNA was similarly associated with inferior DFS (HR, 2.67; 95% CI, 1.28-5.57; P = .009) and inferior OS (HR, 4.16; 95% CI,1.66-10.42; P = .002). The combination of ctDNA and CTCs provided additional information for increased sensitivity and discriminatory capacity. Patients who were ctDNA positive and CTC positive had significantly inferior DDFS compared with those who were ctDNA negative and CTC negative (median DDFS, 32.5 months vs not reached; HR, 5.29; 95% CI, 1.50-18.62; P = .009). At 24 months, DDFS probability was 52% for patients who were ctDNA positive and CTC positive compared with 89% for those who were ctDNA negative and CTC negative. Similar trends were observed for DFS (HR, 3.15; 95% CI, 1.07-9.27; P = .04) and OS (HR, 8.60; 95% CI, 1.78-41.47; P = .007). CONCLUSIONS AND RELEVANCEIn this preplanned secondary analysis of a randomized clinical trial, detection of ctDNA and CTCs in patients with early-stage TNBC after neoadjuvant chemotherapy was independently associated with disease recurrence, which represents an important stratification factor for future pos...