Neoadjuvant radiotherapy of early-stage breast cancer and long-term disease-free survival

Background

Compared with surgery alone, postoperative adjuvant radiotherapy (RT) improves relapse-free survival of patients with early-stage breast cancer. We evaluated the long-term overall and disease-free survival rates of neoadjuvant (presurgical) versus adjuvant RT in early-stage breast cancer patients.

Methods

We used the Surveillance, Epidemiology, and End Results (SEER) database provided by the National Institutes of Health to derive an analytic dataset of 250,195 female patients with early-stage breast cancer who received RT before (n = 2554; 1.02%) or after (n = 247,641; 98.98%) surgery. Disease-free survival, defined as time to diagnosis of a second primary tumor at any location, was calculated from automated patient identification matching of all SEER records.

Results

Partial and complete mastectomies were performed in 94.4% and 5.6% of patients, respectively. In the largest cohort of estrogen receptor-positive women who underwent partial mastectomy, the HR of developing a second primary tumor after neoadjuvant compared with adjuvant RT was 0.64 (95% CI 0.55–0.75; P < 0.0001). Overall survival was independent of radiation sequence (HR 1; P = 0.95). Neoadjuvant RT also resulted in a lower HR for second primary cancer among estrogen receptor-positive patients who underwent mastectomy compared with those who received adjuvant RT (HR 0.48, 95% CI 0.26–0.87; P = 0.0162).

Conclusions

Neoadjuvant RT may significantly improve disease-free survival without reducing overall survival, especially for estrogen receptor-positive patients with early-stage breast cancer. This finding warrants further exploration of potential long-term benefits of neoadjuvant radiotherapy for early-stage breast cancer in a controlled, prospective clinical trial setting, with correlative studies done to identify potential mechanisms of superiority.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0870-1) contains supplementary material, which is available to authorized users.

NCCN Guidelines Insights: Breast Cancer, Version 1.2017

These NCCN Guidelines Insights highlight the important updates/changes to the surgical axillary staging, radiation therapy, and systemic therapy recommendations for hormone receptor-positive disease in the 1.2017 version of the NCCN Guidelines for Breast Cancer. This report summarizes these updates and discusses the rationale behind them. Updates on new drug approvals, not available at press time, can be found in the most recent version of these guidelines at NCCN.org.

Abstract P2-05-18: Correlation of breast cancer index (BCI) risk classification with tumor grade and Ki-67 in a large series of patients with early-stage, ER+ breast cancer

Background: Breast Cancer Index (BCI) is a gene expression-based test that integrates biomarker panels of both proliferation (molecular grade index, MGI), and endocrine response (HoxB13/IL17BR). BCI has been validated as a significant and independent prognostic factor both for risk of overall (0-10y) and late (&gt;5y) distant recurrence, and is predictive of extended endocrine benefit in patients with early-stage, ER+ breast cancer. In this study, correlative analyses of risk stratification by BCI and MGI versus tumor grade or Ki67 were assessed to characterize their relationship to other markers of proliferation.

Methods: Retrospective analysis of consecutive cases (N=1359) from node negative early-stage breast cancer patients submitted for clinical testing with BCI were analyzed. Median age at diagnosis was 58 years, 57% and 6% were HER2 negative and positive, respectively, with 37% unknown status. Tumor grade and Ki67 information was abstracted from pathology reports, and was available for 1335 and 372 cases, respectively. 29%, 52% and 17% of patients had grade 1, 2 and 3 tumors, respectively, with 2% having unknown grade. Tumor sizes were 26% (≤ 1cm), 48% (&gt;1 - ≤ 2cm), 23% (&gt;2 - ≤ 5cm), 2% (≥ 5cm) and 1% were unknown. Ki67 categories were based on 10% and 20% IHC expression levels into low, intermediate and high groups. Statistical methods included Pearson correlation between BCI/MGI versus Ki67 as continuous variables & coefficient of determination derived from the analysis of variance (ANOVA) model between continuous BCI/MGI versus tumor grade. Chi-square test assessed the significance of concordance between BCI, MGI risk groups to tumor grade and Ki67 groups.

Results: As continuous variables, BCI and MGI correlated weakly with tumor grade (coefficient of determination= 0.26 and 0.22, respectively) and Ki67 (r2 = 0.35 and 0.33, respectively). Although statistically significant concordance was demonstrated between BCI/tumor grade, MGI/tumor grade, BCI/Ki67, MGI/Ki67 categories (p&lt;0.0001 for all, Tables 1 & 2), discordance between BCI versus tumor grade or Ki67 was 51% and 45%, respectively. In particular, BCI classified 4% of well differentiated tumors as high-risk and 18% of poorly differentiated tumors as low-risk. Similarly, BCI classified 4% of low Ki67 patients as high risk and 28% of high Ki67 patients as low risk.

Table 1: BCI risk classification vs tumor grade Grade 1Grade 2Grade 3BCI Low Risk30536542BCI Intermediate Risk6921656BCI High Risk15130137

Table 2: BCI risk classification vs Ki67 Ki67 LowKi67 IntermediateKi67 HighBCI Low Risk1094740BCI Intermediate Risk213645BCI High Risk6860

Conclusions: Data from this large retrospective analysis show that correlation of BCI and its mitogenic panel, MGI, to tumor grade and Ki67 are moderate to weak. These findings indicate that BCI and MGI are capturing distinct information related to tumor proliferative status compared with tumor grade and Ki67.

Citation Format: Soliman H, Schroeder BE, Zhang Y, Magliocco AM, Schnabel CA. Correlation of breast cancer index (BCI) risk classification with tumor grade and Ki-67 in a large series of patients with early-stage, ER+ breast cancer [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 P2-05-18.

Phase II, randomized, placebo-controlled study of dovitinib in combination with fulvestrant in postmenopausal patients with HR+, HER2- breast cancer that had progressed during or after prior endocrine therapy

Background

Overexpression of fibroblast growth factor receptor 1 (FGFR1), found in ≤8% of hormone receptor–positive (HR⁺), human epidermal growth factor receptor 2–negative (HER2⁻) breast cancer cases, is correlated with decreased overall survival and resistance to endocrine therapy (ET). Dovitinib, a potent FGFR inhibitor, has demonstrated antitumor activity in heavily pretreated patients with FGFR pathway–amplified breast cancer.

Methods

In this randomized, placebo-controlled phase II trial, we evaluated whether the addition of dovitinib to fulvestrant would improve outcomes in postmenopausal patients with HR⁺, HER2⁻ advanced breast cancer that had progressed during or after prior ET. Patients were stratified by FGF pathway amplification and presence of visceral disease, and they were randomized 1:1 to receive fulvestrant plus dovitinib or placebo. The primary endpoint was progression-free survival (PFS).

Results

From 15 May 2012 to 26 November 2014, 97 patients from 36 centers were enrolled. The frequency of FGF pathway amplification was lower than anticipated, and the study was terminated early owing to slow accrual of patients with FGF pathway amplification. The median PFS (95% CI) was 5.5 (3.8–14.0) months vs 5.5 (3.5–10.7) months in the dovitinib vs placebo arms, respectively (HR, 0.68; did not meet predefined efficacy criteria). For the FGF pathway–amplified subgroup (n = 31), the median PFS (95% CI) was 10.9 (3.5–16.5) months vs 5.5 (3.5–16.4) months in the dovitinib vs placebo arms, respectively (HR, 0.64; met the predefined superiority criteria). Frequently reported adverse events in the dovitinib (diarrhea, nausea, vomiting, asthenia, and headache) and placebo (diarrhea, fatigue, nausea, and asthenia) arms were mostly low grade.

Conclusions

The safety profile of dovitinib plus fulvestrant was consistent with the known safety profile of single-agent dovitinib. Dovitinib in combination with fulvestrant showed promising clinical activity in the FGF pathway–amplified subgroup. However, the data reported herein should be interpreted with caution, given that fewer PFS events occurred in the FGF pathway–amplified patients than was expected and that an effect of dovitinib regardless of FGR pathway amplification status cannot be excluded, because the population was smaller than expected.

Trial registration

ClinicalTrials.gov identifier: NCT01528345. Registered 31 January 2012.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0807-8) contains supplementary material, which is available to authorized users.

Bone-Seeking Matrix Metalloproteinase-2 Inhibitors Prevent Bone Metastatic Breast Cancer Growth

Bone metastasis is common during breast cancer progression. Matrix metalloproteinase-2 (MMP-2) is significantly associated with aggressive breast cancer and poorer overall survival. In bone, tumor- or host-derived MMP-2 contributes to breast cancer growth and does so by processing substrates, including type I collagen and TGFβ latency proteins. These data provide strong rationale for the application of MMP-2 inhibitors to treat the disease. However, in vivo, MMP-2 is systemically expressed. Therefore, to overcome potential toxicities noted with previous broad-spectrum MMP inhibitors (MMPIs), we used highly selective bisphosphonic-based MMP-2 inhibitors (BMMPIs) that allowed for specific bone targeting. In vitro, BMMPIs affected the viability of breast cancer cell lines and osteoclast precursors, but not osteoblasts. In vivo, we demonstrated using two bone metastatic models (PyMT-R221A and 4T1) that BMMPI treatment significantly reduced tumor growth and tumor-associated bone destruction. In addition, BMMPIs are superior in promoting tumor apoptosis compared with the standard-of-care bisphosphonate, zoledronate. We demonstrated MMP-2-selective inhibition in the bone microenvironment using specific and broad-spectrum MMP probes. Furthermore, compared with zoledronate, BMMPI-treated mice had significantly lower levels of TGFβ signaling and MMP-generated type I collagen carboxy-terminal fragments. Taken together, our data show the feasibility of selective inhibition of MMPs in the bone metastatic breast cancer microenvironment. We posit that BMMPIs could be easily translated to the clinical setting for the treatment of bone metastases given the well-tolerated nature of bisphosphonates. Mol Cancer Ther; 16(3); 494-505. ©2017 AACR.

Ramucirumab With Eribulin Versus Eribulin in Locally Recurrent or Metastatic Breast Cancer Previously Treated With Anthracycline and Taxane Therapy: A Multicenter, Randomized, Phase II Study

BACKGROUND

Use of antiangiogenic agents in treatment of metastatic breast cancer (MBC) remains controversial. We evaluated the efficacy and safety of ramucirumab and eribulin versus eribulin alone as third- to fifth-line therapy in women with advanced breast cancer.

PATIENTS AND METHODS

In this randomized (1:1), open-label, phase II study, US women aged 18 years or older with 2 to 4 previous chemotherapy regimens for locally recurrent or MBC, previous anthracycline and taxane treatment, and Eastern Cooperative Oncology Group performance status of 0 or 1 received ramucirumab with eribulin or eribulin alone in 21-day cycles (eribulin 1.4 mg/m2 intravenously on days 1 and 8; ramucirumab 10 mg/kg intravenously on day 1). Randomization was stratified according to previous antiangiogenic therapy and triple-negative status. The primary end point was progression-free survival (PFS) in the intention to treat population.

RESULTS

One hundred forty-one women were randomized to ramucirumab with eribulin (n = 71) or eribulin alone (n = 70). Median PFS for ramucirumab with eribulin was 4.4 months (95% confidence interval [CI], 3.1-6.7) compared with 4.1 months (95% CI, 3.2-5.6) for eribulin (hazard ratio [HR], 0.83; 95% CI, 0.56-1.23; P = .35). Median overall survival in patients who received ramucirumab with eribulin was 13.5 months (95% CI, 10.4-17.9) compared with 11.5 months (95% CI, 9.0-17.3) in patients who received eribulin alone (HR, 0.91; 95% CI, 0.59-1.41; P = .68); objective response rate was 21% (13 of 62 patients) for the combination and 28% (17 of 60 patients) for eribulin alone. No unexpected toxicity was identified for the combination.

CONCLUSION

Ramucirumab combined with eribulin did not significantly improve PFS in advanced MBC.

Nucleolar repression facilitates initiation and maintenance of senescence

Tumor cells with defective apoptosis pathways often respond to chemotherapy by entering irreversible cell cycle arrest with features of senescence. However, rare cells can bypass entry to senescence, or re-enter cell cycle from a senescent state. Deficiency in senescence induction and maintenance may contribute to treatment resistance and early relapse after therapy. Senescence involves epigenetic silencing of cell cycle genes and reduced rRNA transcription. We found that senescence-inducing treatments such as DNA damage and RNA polymerase I inhibition stimulate the binding between the nucleolar protein NML (nucleomethylin) and SirT1. The NML complex promotes rDNA heterochromatin formation and represses rRNA transcription. Depletion of NML reduced the levels of H3K9Me3 and H3K27Me3 heterochromatin markers on rDNA and E2F1 target promoters in senescent cells, increased rRNA transcription, and increased the frequency of cell cycle re-entry. Depletion of the nucleolar transcription repressor factor TIP5 also promoted escape from senescence. Furthermore, tumor tissue staining showed that breast tumors without detectable nucleolar NML expression had poor survival. The results suggest that efficient regulation of nucleolar rDNA transcription facilitates the maintenance of irreversible cell cycle arrest in senescent cells. Deficiency in nucleolar transcription repression may accelerate tumor relapse after chemotherapy.

Abstract 3144: Detection of HER2-HER3 heterodimers in patient circulating tumor cells using proximity ligation assay

BACKGROUND: The HER2 protein is a key oncogene in approximately 20% of breast cancers, and preferentially forms heterodimers with other members of the HER family (such as HER3) to activate its signaling cascade. Dual HER2 signaling blockade by using both trastuzumab and pertuzumab (a HER2 dimerization inhibiting monoclonal antibody) yields superior clinical benefit in HER2+ patients compared to trastuzumab monotherapy. A phase 1/2 clinical trial is ongoing to assess the safety and efficacy of the combination of gemcitabine with trastuzumab and pertuzumab in metastatic HER2+ pretreated patients. (NCT02139358) One of the correlative experiments is looking at the feasibility of detecting HER2-HER3 heterodimers using a proximity ligation assay on circulating tumor cells isolated from patients on treatment as a possible pharmcodynamic marker.

METHODS: Whole blood was collected in two 10cc Cellsave tubes (Veridex, Cat#: 7900005) at baseline, week 4, 7, 10. Samples were drawn before treatment was administered, to avoid contamination of the samples with cytotoxic agents. The blood was subjected to red cell lysis with 1XRBC lysis buffer (Santa Cruz). The lysed cells were fixed with 4% paraformaldehyde followed by negative selection utilizing CD45+ magnetic beads (EasySep CD45 depletion kit, cat#18259). The CD45 depleted cell suspension was re-fixed with 4% PFA on coated glass slides following cytospin. These cells were then stained for PLA to test for HER2-HER3 using Sigma Aldrich DuoLink PLA kit + DAPI fluorescence mounting medium (DUO92013) with anti-HER2 (PA5, Thermo Scientific, diluted 1:50) and anti-HER3 (MA5-12675, Thermo Scientific diluted 1:50) as primary antibodies plus cytokeratin (CK) and CD45 antibodies. A set of HER2+ and HER2- PLA controls using SKBR3 were included in the analysis. Control samples using SKBR3 cells were used to optimize the method.

RESULTS: Using the spiked SKBR3 HER2+ blood samples it was possible to isolate CK+ CD45- DAPI+ CTCs demonstrating HER2-HER3 heterodimers following optimization of the PLA method. Using this method in the first four patients we successfully collected CTCs in 7/11 samples processed. In those 7 CTC+ samples, 4 contained CTCs with positive HER2-HER3 PLA signals.

CONCLUSIONS: We have demonstrated a feasible methodology for the detection of HER2-HER3 heterodimers on the surface of circulating tumor cells from HER2+ metastatic breast cancer patients. This can provide investigators with a non-invasive method to monitor the pharmacodynamics of pertuzumab therapy on tumor cells. The collection of these samples is ongoing and correlation with benefit from therapy will be analyzed in the phase 2 portion of the study.

Citation Format: Hatem Soliman, Fatema Khambati. Detection of HER2-HER3 heterodimers in patient circulating tumor cells using proximity ligation assay. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3144.

Attenuation of obesity-induced insulin resistance in mice with heterozygous deletion of ROCK2

BACKGROUND/OBJECTIVES

Obesity-associated insulin resistance is a major risk factor for the development of type 2 diabetes, cardiovascular disease and non-alcoholic liver disease. Over-activation of the RhoA-Rho kinase (ROCK) pathway has been implicated in the development of obesity-induced insulin resistance, but the relative contribution of ROCK2 has not been elucidated. This was investigated in the present study.

METHODS

Male ROCK2+/- mice and their wild-type (WT) littermate controls were fed normal chow or a high fat diet (HFD) for 18 weeks. Glucose and insulin tolerance tests were conducted 8 and 16 weeks after the start of feeding. At termination, isoform-specific ROCK activity and insulin signaling were evaluated in epididymal adipose tissue. Adipocyte size was assessed morphometrically, while adipose tissue production of PPARγ was determined by western blotting, and inflammatory cytokines were evaluated by RT-PCR and immunofluorescence.

RESULTS

The decrease in systemic insulin sensitivity and glucose tolerance produced by high fat feeding was attenuated in ROCK2+/- mice. There was no reduction in food intake, body weight or epididymal fat pad weight in HFD-ROCK2+/- mice. However, the increase in adipocyte size detected in HFD-WT mice was attenuated in HFD-ROCK2+/- mice. The increase in adipose tissue ROCK2 activity produced by high fat feeding in WT mice was also prevented in ROCK2+/- mice, and this was accompanied by improved insulin-induced phosphorylation of Akt. The expression of both isoforms of PPARγ was increased in adipose tissue from HFD-ROCK2+/- mice, while adipocyte hypertrophy and production of inflammatory cytokines were reduced compared with HFD-WT mice.

CONCLUSIONS

These data suggest that activation of ROCK2 in adipose tissue contributes to obesity-induced insulin resistance. This may result in part from suppression of PPARγ expression, leading to adipocyte hypertrophy and an increase in inflammatory cytokine production. ROCK2 may be a suitable target to improve insulin sensitivity in obesity.