The prognostic value of the neoadjuvant response index in triple-negative breast cancer: validation and comparison with pathological complete response as outcome measure

High-dose alkylating chemotherapy in BRCA-altered triple-negative breast cancer: the randomized phase III NeoTN trial

Exploratory analyses of high-dose alkylating chemotherapy trials have suggested that BRCA1 or BRCA2-pathway altered (BRCA-altered) breast cancer might be particularly sensitive to this type of treatment. In this study, patients with BRCA-altered tumors who had received three initial courses of dose-dense doxorubicin and cyclophosphamide (ddAC), were randomized between a fourth ddAC course followed by high-dose carboplatin-thiotepa-cyclophosphamide or conventional chemotherapy (initially ddAC only or ddAC-capecitabine/decetaxel [CD] depending on MRI response, after amendment ddAC-carboplatin/paclitaxel [CP] for everyone). The primary endpoint was the neoadjuvant response index (NRI). Secondary endpoints included recurrence-free survival (RFS) and overall survival (OS). In total, 122 patients were randomized. No difference in NRI-score distribution (p = 0.41) was found. A statistically non-significant RFS difference was found (HR 0.54; 95% CI 0.23-1.25; p = 0.15). Exploratory RFS analyses showed benefit in stage III (n = 35; HR 0.16; 95% CI 0.03-0.75), but not stage II (n = 86; HR 1.00; 95% CI 0.30-3.30) patients. For stage III, 4-year RFS was 46% (95% CI 24-87%), 71% (95% CI 48-100%) and 88% (95% CI 74-100%), for ddAC/ddAC-CD, ddAC-CP and high-dose chemotherapy, respectively. No significant differences were found between high-dose and conventional chemotherapy in stage II-III, triple-negative, BRCA-altered breast cancer patients. Further research is needed to establish if there are patients with stage III, triple negative BRCA-altered breast cancer for whom outcomes can be improved with high-dose alkylating chemotherapy or whether the current standard neoadjuvant therapy including carboplatin and an immune checkpoint inhibitor is sufficient. Trial Registration: NCT01057069.

Comprehensive characterization of pre- and post-treatment samples of breast cancer reveal potential mechanisms of chemotherapy resistance

When locally advanced breast cancer is treated with neoadjuvant chemotherapy, the recurrence risk is significantly higher if no complete pathologic response is achieved. Identification of the underlying resistance mechanisms is essential to select treatments with maximal efficacy and minimal toxicity. Here we employed gene expression profiles derived from 317 HER2-negative treatment-naïve breast cancer biopsies of patients who underwent neoadjuvant chemotherapy, deep whole exome, and RNA-sequencing profiles of 22 matched pre- and post-treatment tumors, and treatment outcome data to identify biomarkers of response and resistance mechanisms. Molecular profiling of treatment-naïve breast cancer samples revealed that expression levels of proliferation, immune response, and extracellular matrix (ECM) organization combined predict response to chemotherapy. Triple negative patients with high proliferation, high immune response and low ECM expression had a significantly better treatment response and survival benefit (HR 0.29, 95% CI 0.10–0.85; p = 0.02), while in ER+ patients the opposite was seen (HR 4.73, 95% CI 1.51–14.8; p = 0.008). The characterization of paired pre-and post-treatment samples revealed that aberrations of known cancer genes were either only present in the pre-treatment sample (CDKN1B) or in the post-treatment sample (TP53, APC, CTNNB1). Proliferation-associated genes were frequently down-regulated in post-treatment ER+ tumors, but not in triple negative tumors. Genes involved in ECM were upregulated in the majority of post-chemotherapy samples. Genomic and transcriptomic differences between pre- and post-chemotherapy samples are common and may reveal potential mechanisms of therapy resistance. Our results show a wide range of distinct, but related mechanisms, with a prominent role for proliferation- and ECM-related genes.

Prognostic Value of Residual Disease after Neoadjuvant Therapy in HER2-Positive Breast Cancer Evaluated by Residual Cancer Burden, Neoadjuvant Response Index, and Neo-Bioscore

PURPOSE

In breast cancer, pathologic complete response (pCR) to neoadjuvant systemic therapy (NST) is associated with favorable long-term outcome. Trastuzumab emtansine as additional adjuvant therapy improves recurrence-free survival of patients with HER2-positive breast cancer without pCR, but it is uncertain whether all patients without pCR need additional therapy. We evaluated the prognostic value of residual disease after trastuzumab-based NST in patients with HER2-positive breast cancer using Residual Cancer Burden (RCB), Neoadjuvant Response Index (NRI), and Neo-Bioscore.

EXPERIMENTAL DESIGN

We included patients with stage II or III HER2-positive breast cancer treated with trastuzumab-based NST and surgery at The Netherlands Cancer Institute between 2004 and 2016. RCB, NRI, and Neo-Bioscore were determined. Primary endpoint was 5-year recurrence-free interval (RFI). A 3% difference compared with the pCR group was considered acceptable as noninferiority margin on the 5-year RFI estimate, based on a proportional hazards model, and its lower 95% confidence boundary.

RESULTS

A total of 283 women were included. Median follow-up was 67 months (interquartile range 44-100). A total of 157 patients (56%) with pCR (breast and axilla) had a 5-year RFI of 92% (95% CI, 88-97); patients without pCR had a 5-year RFI of 80% (95% CI, 72-88). Patients with an RCB = 1 (N = 40, 15%), an NRI score between 0.75 and 0.99 (N = 30, 11%), or a Neo-Bioscore of 0 to 1 (without pCR; N = 28, 11%) have a 5-year RFI that falls within a predefined noninferiority margin of 3% compared with patients with pCR.

CONCLUSIONS

The RCB, NRI, and Neo-Bioscore can identify patients with HER2-positive breast cancer with minimal residual disease (i.e., RCB = 1, NRI ≥ 0.75, or Neo-Bioscore = 0-1) after NST who have similar 5-year RFI compared with patients with pCR.

Neoadjuvant Bevacizumab plus Chemotherapy versus Chemotherapy Alone to Treat Non-Metastatic Breast Cancer: A Meta-Analysis of Randomised Controlled Trials

Purpose

Results from previous randomised controlled trials (RCTs) investigating whether the addition of bevacizumab to neoadjuvant chemotherapy (NAC) could statistically significantly increase the pathological complete response (pCR) and to identify which subgroup would benefit most from such regimens have produced conflicting results. This meta-analysis was designed to assess the efficacy and safety of bevacizumab plus chemotherapy compared with chemotherapy alone in the neoadjuvant setting.

Methods

A literature search of MEDLINE, EMBASE, Web of Science, and the Cochrane library was performed to identify eligible studies. The primary endpoint of interest was pCR. The secondary endpoints were clinical complete rate (cCR), surgery rate, breast-conserving surgery (BCS) rate, and toxicity. The meta-analysis was performed using Review Manager software version 5.3.

Results

Nine RCTs matched the selection criteria, yielding a total of 4967 patients (bevacizumab plus chemotherapy: 50.1%, chemotherapy alone: 49.9%). The results of this meta-analysis demonstrated that the addition of bevacizumab to NAC significantly increased the pCR rate (odds ratio [OR] = 1.34 [1.18–1.54]; P < 0.0001) compared with chemotherapy alone. Subgroup analysis showed that the effect of bevacizumab was more pronounced in patients with HER2-negative cancer (OR = 1.34 [1.17–1.54]; P < 0.0001) compared with HER2-positive cancer (OR = 1.69 [0.90–3.20]; P = 0.11). Similarly, in patients with HER2-negative cancer, the effect of bevacizumab was also more pronounced in patients with HR-negative cancer (OR = 1.38 [1.09–1.74]; P = 0.007) compared with HR-positive cancer (OR = 1.36 [0.78–2.35]; P = 0.27). No significant differences were observed between the groups with respect to cCR, surgery rate, or BCS rate. Additionally bevacizumab was associated with a higher incidence of neutropenia, febrile neutropenia, and hand–foot syndrome.

Conclusions

Higher proportions of patients achieved pCR when bevacizumab was added to NAC compared with when they received chemotherapy alone; acceptable toxicities were also found. Subgroup analysis demonstrated that patients with histologically confirmed HER2-negative and HR-negative breast cancer benefited the most.