Neoadjuvant chemotherapy in breast cancer: what questions remain?

Synchronous bilateral breast cancer with heterogeneous hormone receptor status: a case report

The expression of estrogen, progesterone, and HER2 receptors in breast cancer cells helps guide treatment and predict outcomes. When the status of these receptors is heterogeneous, it makes treatment planning more complex. We present the case of a 72-year-old woman with bilateral breast cancer with heterogenous receptor status and subsequent challenges in management.

The Impact of Neoadjuvant Chemotherapy on Patients With T1N0M0 Triple-Negative and HER-2 Positive Breast Cancer: A Retrospective Analysis Based on the SEER Database

BACKGROUND

The utilization of neoadjuvant chemotherapy (NAC) originated in the treatment of locally advanced breast cancer (BC). Our study is designed to elucidate the effects of NAC on patients with T1N0M0 triple-negative and HER-2 positive BC.

METHODS

This study involved the selection of 10,614 patients diagnosed with T1N0M0 triple-negative and HER-2 positive breast cancer (BC) from the surveillance, epidemiology, and end results (SEER) database. To ascertain the impact of neoadjuvant chemotherapy (NAC) on T1a, T1b, and T1c N0M0 BC, we conducted multivariate Cox regression analyses. Similarly, we performed multivariate Cox regression analyses to compare the effects of neoadjuvant chemotherapy against adjuvant chemotherapy on T1N0M0 BC. The Kaplan-Meier method was employed to delineate survival curves for different molecular subtypes and clinical stages.

RESULTS

The data results from the SEER database reveal a significant enhancement of overall survival (OS) in T1c BC patients as a result of NAC. For T1b BC patients, NAC does not present any significant effect. Contrarily, NAC seems to adversely impact the OS of T1a triple-negative BC patients. However, the prognosis comparison between neoadjuvant and adjuvant chemotherapy for T1N0M0 breast cancer did not show any significant difference, with the exception of T1a triple-negative BC.

CONCLUSIONS

Patients with T1cN0M0 triple-negative and HER-2 positive BC may derive OS benefits from NAC. Additionally, NAC could be detrimental to T1a triple-negative BC.

In Vitro and In Vivo Effects of Docetaxel and Dasatinib in Triple-Negative Breast Cancer: A Research Study

Introduction Triple-negative breast cancer (TNBC) comprises a heterogeneous group of tumors with a single trait in common: an evident aggressive nature with higher rates of relapse and lower overall survival in the metastatic context when compared to other subtypes of breast cancer. To date, not a single targeted therapy has been approved for the treatment of TNBC, and cytotoxic chemotherapy remains the standard treatment. In the present experimental study, we examine the effects of the chemotherapeutic docetaxel and the bcr/abl kinase inhibitor dasatinib on TNBC cell lines (in vitro) and on TNBC tumor xenograft mouse models (in vivo). Materials and methods TNBC cell lines were cultivated and treated with various concentrations of docetaxel and dasatinib (5 nM to 100 nM). Cell death and apoptosis were studied by flow cytometry. TNBC cell lines were then injected in BALB/c athymic nude mice to express the tumor in vivo. Four groups of mice were created (group A: control; group B: DOC; group C: DAS; group D: DOC + DAS) and treated, respectively, with the drugs and their combination. Tumors were obtained, maintained in a 10% formaldehyde solution, embedded in paraffin, and sent for further histological evaluation (hematoxylin-eosin staining and immune-histochemical analysis) to assess the tumor growth inhibition. Results The cytotoxic effects of docetaxel seem statistically important, with little effect on apoptosis. The effect of dasatinib in vitro and vivo is statistically important, in terms of apoptosis and tumor reduction, with little adverse effects. Conclusions TNBC is a difficult-to-treat oncologic condition, even in an experimental setting. Promising results concerning the addition of targeted therapies (dasatinib) to the conventional cytotoxic ones (docetaxel) have been shown, awaiting further evaluation.

Synchronous Bilateral Breast Cancer With Discordant Receptor Status: Treating One Patient but Two Diseases

The expression of hormone receptors (estrogen and progesterone) and human epidermal growth factor receptor-2 (HER2) has been used for both therapeutic and prognostic purposes in the management of breast cancer. The presence of a discordant receptor status complicates the approach to treatment in patients with synchronous bilateral breast cancer. We describe the case of a 45-year-old female with synchronous bilateral breast cancer with a triple-negative tumor and a contralateral HER2-positive tumor and discussed the impact of this on the approach to therapeutic management.

Neoadjuvant Chemotherapy for Breast Cancer: Past, Present, and Future

Neoadjuvant chemotherapy (NAC) had been developed as a systematic approach before definitive surgery for the treatment of locally advanced or inoperable breast cancer such as inflammatory breast cancer in the past. In addition to its impact on surgery, the neoadjuvant setting has a benefit of providing the opportunity to monitor the individual drug response. Currently, the subject of NAC has expanded to include patients with early-stage, operable breast cancer because it is revealed that the achievement of a pathologic complete response (pCR) is associated with excellent long-term outcomes, especially in patients with aggressive phenotype breast cancer. In addition, this approach provides the unique opportunity to escalate adjuvant therapy in those with residual disease after NAC. Neoadjuvant chemotherapy in breast cancer is a rapidly evolving topic with tremendous interest in ongoing clinical trials. Here, we review the improvements and further challenges in the NAC setting in translational breast cancer research.

Effects of CDK4/6 Inhibition in Hormone Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Cells with Acquired Resistance to Paclitaxel

Among patients with hormone receptor (HR)-positive breast cancer, those with residual disease after neoadjuvant chemotherapy have a higher risk of relapse and poorer survival than those with a complete response. Previous studies have revealed a correlation between activation of cell cycle-regulating pathways in HR-positive breast cancer, particularly cyclin-dependent kinase (CDK) 4 and 6/cyclin D1 signaling, and resistance to standard therapies. Although CDK4/6 inhibition by palbociclib in combination with endocrine therapy has shown potent antiproliferative effects in HR-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, the potential role of palbociclib in re-sensitizing chemotherapy-resistant HR-positive breast cancer is not well defined. We hypothesized that CDK4/6 inhibition by palbociclib re-sensitizes HR-positive/HER2-negative residual breast cancer to taxane-based adjuvant therapy. Using cell counting, flow cytometry, and western blotting, we evaluated the efficacy of palbociclib alone and in concurrent or sequential combination with paclitaxel in parental and paclitaxel-resistant T47D HR-positive/HER2-negative breast cancer cells. The CDK4/6 pathway was constitutively active in both parental and paclitaxel-resistant T47D cells; thus, both cell types were highly sensitive to the inhibitory effects of single-agent palbociclib on cell growth and cell cycle progression. However, palbociclib did not re-sensitize resistant cells to paclitaxel-induced G2/M arrest and cell death in any of the combinations tested. Our results suggest that CDK4/6 inhibition by palbociclib does not re-sensitize HR-positive/HER2-negative residual breast cancer to chemotherapy. Nevertheless, the fact that CDK4/6 activation remained intact in paclitaxel-resistant cells indicates that patients who have HR-positive/HER2-negative residual disease after taxane-based neoadjuvant chemotherapy may still benefit from palbociclib in combination with other regimens, such as endocrine therapies, for adjuvant therapy.

Tumor RNA disruption predicts survival benefit from breast cancer chemotherapy

In a prior substudy of the CAN-NCIC-MA.22 clinical trial (ClinicalTrials.gov identifier NCT00066443), we observed that neoadjuvant chemotherapy reduced tumor RNA integrity in breast cancer patients, a phenomenon we term "RNA disruption." The purpose of the current study was to assess in the full patient cohort the relationship between mid-treatment tumor RNA disruption and both pCR post-treatment and, subsequently, disease-free survival (DFS) up to 108 months post-treatment. To meet these objectives, we developed the RNA disruption assay (RDA) to quantify RNA disruption and stratify it into 3 response zones of clinical importance. Zone 1 is a level of RNA disruption inadequate for pathologic complete response (pCR); Zone 2 is an intermediate level, while Zone 3 has high RNA disruption. The same RNA disruption cut points developed for pCR response were then utilized for DFS. Tumor RDA identified >fourfold more chemotherapy non-responders than did clinical response by calipers. pCR responders were clustered in RDA Zone 3, irrespective of tumor subtype. DFS was about 2-fold greater for patients with tumors in Zone 3 compared to Zone 1 patients. Kaplan-Meier survival curves corroborated these findings that high tumor RNA disruption was associated with increased DFS. DFS values for patients in zone 3 that did not achieve a pCR were similar to that of pCR recipients across tumor subtypes, including patients with hormone receptor positive tumors that seldom achieve a pCR. RDA appears superior to pCR as a chemotherapy response biomarker, supporting the prospect of its use in response-guided chemotherapy.