Phase III randomized trial of dose intensive neoadjuvant chemotherapy with or without G-CSF in locally advanced breast cancer: long-term results

Selection of breast cancer subtypes to improve benefits of intensive dose‑dense chemotherapy: A systematic meta‑analysis

Breast cancer (BC) is the most commonly diagnosed cancer and the second leading cause of cancer mortality among women worldwide. A large number of patients experience recurrence and BC-associated mortality following adjuvant chemotherapy. The present study aimed to determine the most suitable pathological subtype of BC to benefit from intensive dose-dense (DD) chemotherapy. A total of four electronic databases were searched from inception up to March 10, 2023. Randomized controlled trials (RCTs) and retrospective studies comparing DD chemotherapy with standard chemotherapy in patients with BC were included. Pairwise random effects and network meta-analyses were performed to summarize efficacy and safety outcomes. A total of 27 original studies including 27,580 patients with BC were included. In terms of efficacy, the present study evaluated overall survival, disease-free survival, event-free survival, recurrence-free survival, pathological complete response and objective remission rate. Significant differences were identified in overall, hormone receptor+ (HR+) and HR- subgroups. Furthermore, from the network analysis, the HR+ and Her2- subgroups had the highest ranking, and these findings suggested that HR+/Her2- patients with BC should adhere to a treatment strategy including intensive DD chemotherapy, which is also characterized by an acceptable safety profile. In conclusion, patients with HR+ and Her2- BC were revealed to be the most suitable pathological type and are most likely to benefit from intense DD chemotherapy. The present study was registered with PROSPERO, CRD2022420351567.

Observation effectiveness of dose-dense neoadjuvant anthracycline sequential weekly paclitaxel for triple-negative breast cancer patients

INTRODUCTION/BACKGROUND

To investigate the differences in pathological response and survival outcomes between dose-dense and conventional-interval neoadjuvant chemotherapy (NAC) in patients with triple-negative breast cancer (TNBC).

PATIENTS AND METHODS

Patients with TNBC who received NAC including epirubicin plus cyclophosphamide followed by weekly paclitaxel were included. A total of 494 patients were divided into either the dose-dense anthracycline (ddEC-wP) group or conventional interval anthracycline (EC-wP) group.

RESULTS

The breast pathological complete response (bpCR, ypT0/is) rate was 45.3% (n = 101) in the dose-dense group and 34.3% (n = 93) in the conventionally scheduled group, which was a significant difference (P = .013), and in the 251 pN+ cases, the lymph node pathological complete response (LNpCR, ypN0) rate was 57.9% (n = 62) in the dose-dense group and 43.7% (n = 63) in the conventionally scheduled group, which was a significant difference (P = .026) in the univariate analysis. In the multivariate logistic regression analysis, 3 variables were predictive of bpCR: pathological type, surgical methods and type of chemotherapy, with P values of .012, .001 and .021, respectively. Two variables were predictive of LNpCR: type of chemotherapy and Her-2 expression, with P values of .039 and .020, respectively. After a median follow-up of 54 months, there was no significant difference in survival for disease-free survival (DFS) (hazard ratio [HR], 0.788; 95% confidence interval [CI], 0.508 to 1.223; P = .288), distant disease-free survival (DDFS) (HR, 0. 709; 95% CI, 0.440 to 1.144; P = .159) or overall survival (OS) (HR, 0. 750; 95% CI, 0.420 to 1.338; P = .330) between the 2 groups.

CONCLUSION

Our study demonstrated that TNBC achieved a higher bpCR rate and LNpCR rate after dose-dense neoadjuvant chemotherapy than the conventional scheme. The survival benefit of the 2 groups did not reach statistical difference.

Evaluation of pathological complete response as surrogate endpoint in neoadjuvant randomised clinical trials of early stage breast cancer: systematic review and meta-analysis

OBJECTIVE

To evaluate pathological complete response as a surrogate endpoint for disease-free survival and overall survival in regulatory neoadjuvant trials of early stage breast cancer.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, and Scopus to 1 December 2020.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Randomised clinical trials that tested neoadjuvant chemotherapy given alone or combined with other treatments, including anti-human epidermal growth factor 2 (anti-HER2) drugs, targeted treatments, antivascular agents, bisphosphonates, and immune checkpoint inhibitors.

DATA EXTRACTION AND SYNTHESIS

Trial level associations between the surrogate endpoint pathological complete response and disease-free survival and overall survival.

METHODS

A weighted regression analysis was performed on log transformed treatment effect estimates (hazard ratio for disease-free survival and overall survival and relative risk for pathological complete response), and the coefficient of determination (R2) was used to quantify the association. The secondary objective was to explore heterogeneity of results in preplanned subgroups analysis, stratifying trials according treatment type in the experimental arm, definition used for pathological complete response (breast and lymph nodes v breast only), and biological features of the disease (HER2 positive or triple negative breast cancer). The surrogate threshold effect was also evaluated, indicating the minimum value of the relative risk for pathological complete response necessary to confidently predict a non-null effect on hazard ratio for disease-free survival or overall survival.

RESULTS

54 randomised clinical trials comprising a total of 32 611 patients were included in the analysis. A weak association was observed between the log(relative risk) for pathological complete response and log(hazard ratio) for both disease-free survival (R2=0.14, 95% confidence interval 0.00 to 0.29) and overall survival (R2 =0.08, 0.00 to 0.22). Similar results were found across all subgroups evaluated, independently of the definition used for pathological complete response, treatment type in the experimental arm, and biological features of the disease. The surrogate threshold effect was 5.19 for disease-free survival but was not estimable for overall survival. Consistent results were confirmed in three sensitivity analyses: excluding small trials (<200 patients enrolled), excluding trials with short median follow-up (<24 months), and replacing the relative risk for pathological complete response with the absolute difference of pathological complete response rates between treatment arms.

CONCLUSION

A lack of surrogacy of pathological complete response was identified at trial level for both disease-free survival and overall survival. The findings suggest that pathological complete response should not be used as primary endpoint in regulatory neoadjuvant trials of early stage breast cancer.

Genomic Assays in Node Positive Breast Cancer Patients: A Review

In recent years, developments in breast cancer have allowed yet another realization of individualized medicine in the field of oncology. One of these advances is genomic assays, which are considered elements of standard clinical practice in the management of breast cancer. These assays are widely used today not only to measure recurrence risk in breast cancer patients at an early stage but also to tailor treatment as well and minimize avoidable treatment side effects. At present, genomic tests are applied extensively in node negative disease. In this article, we review the use of these tests in node positive disease, explore their ramifications on neoadjuvant chemotherapy decisions, highlight sufficiently powered recent studies emphasizing their use and review the most recent guidelines.

Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer: ASCO Guideline

PURPOSE

To develop guideline recommendations concerning optimal neoadjuvant therapy for breast cancer.

METHODS

ASCO convened an Expert Panel to conduct a systematic review of the literature on neoadjuvant therapy for breast cancer and provide recommended care options.

RESULTS

A total of 41 articles met eligibility criteria and form the evidentiary basis for the guideline recommendations.

RECOMMENDATIONS

Patients undergoing neoadjuvant therapy should be managed by a multidisciplinary care team. Appropriate candidates for neoadjuvant therapy include patients with inflammatory breast cancer and those in whom residual disease may prompt a change in therapy. Neoadjuvant therapy can also be used to reduce the extent of local therapy or reduce delays in initiating therapy. Although tumor histology, grade, stage, and estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2) expression should routinely be used to guide clinical decisions, there is insufficient evidence to support the use of other markers or genomic profiles. Patients with triple-negative breast cancer (TNBC) who have clinically node-positive and/or at least T1c disease should be offered an anthracycline- and taxane-containing regimen; those with cT1a or cT1bN0 TNBC should not routinely be offered neoadjuvant therapy. Carboplatin may be offered to patients with TNBC to increase pathologic complete response. There is currently insufficient evidence to support adding immune checkpoint inhibitors to standard chemotherapy. In patients with hormone receptor (HR)-positive (HR-positive), HER2-negative tumors, neoadjuvant chemotherapy can be used when a treatment decision can be made without surgical information. Among postmenopausal patients with HR-positive, HER2-negative disease, hormone therapy can be used to downstage disease. Patients with node-positive or high-risk node-negative, HER2-positive disease should be offered neoadjuvant therapy in combination with anti-HER2-positive therapy. Patients with T1aN0 and T1bN0, HER2-positive disease should not be routinely offered neoadjuvant therapy.Additional information is available at www.asco.org/breast-cancer-guidelines.

Chemoresistance in Breast Cancer Patients Associated With Changes in P2X7 and A2A Purinergic Receptors in CD8+ T Lymphocytes

Breast cancer (BRCA) is the most frequent cancer type that afflicts women. Unfortunately, despite all the current therapeutic strategies, many patients develop chemoresistance hampering the efficacy of treatment. Hence, an early indicator of therapy efficacy might aid in the search for better treatment and patient survival. Although emerging evidence indicates a key role of the purinergic receptors P2X7 and A2A in cancer, less is known about their involvement in BRCA chemoresistance. In this sense, as the chemotherapeutic treatment stimulates immune system response, we evaluated the expression and function of P2X7 and A2A receptors in CD8⁺ T cells before and four months after BRCA patients received neoadjuvant chemotherapy. The results showed an increase in the levels of expression of P2X7 and a decrease in the expression of A2A in CD8⁺ T cells in non-chemoresistant (N-CHR) patients, compared to chemoresistant (CHR) patients. Interestingly, in CHR patients, reduced expression of P2X7 occurs along with a decrease in the CD62L shedding and the production of IFN-γ. In the case of the A2A function, the inhibition of IFN-γ production was not observed after chemotherapy in CHR patients. A possible relationship between the modulation of the expression and function of the P2X7 and A2A receptors was found, according to the molecular subtypes, where the patients that were triple-negative and human epidermal growth factor receptor 2 (HER2)-enriched presented more alterations. Comorbidities such as overweight/obesity and type 2 diabetes mellitus (T2DM) participate in the abnormalities detected. Our results demonstrate the importance of purinergic signaling in CD8⁺ T cells during chemoresistance, and it could be considered to implement personalized therapeutic strategies.

Does dose-dense neoadjuvant chemotherapy have clinically significant prognostic value in breast cancer?: A meta-analysis of 3,724 patients

Purpose

Neoadjuvant chemotherapy (NCT) is typically the initial treatment for non-early breast cancer patients. We thereby conducted a meta-analysis to explore whether dose-dense neoadjuvant chemotherapy (ddNCT) improved the long-term prognosis of patients compared to the standard NCT regimen.

Methods

We compared the differences in efficacy and prognosis between patients receiving standard NCT and ddNCT. We also calculated the pooled odds ratio (OR) of pathological complete response (pCR) and the pooled hazard ratio (HR) of overall survival (OS) and disease-free survival (DFS).

Results

Nine randomized controlled trials involving 3,724 patients from 10 published studies were included in the meta-analysis. The pooled OR for ddNCT was 1.18 (95% confidence interval (CI): 0.83–1.67, P = 0.356). A subgroup analysis in the cases with low hormone receptor expression levels showed the pCR in patients undergoing ddNCT was significantly higher than the pCR in patients undergoing standard NCT (OR = 1.36, 95% CI: 1.09‒1.69, P = 0.007). There was no significant difference in DFS and OS between ddNCT and standard NCT (DFS: HR = 0.90, 95% CI: 0.79‒1.02, P = 0.095; OS; HR = 0.91, 95% CI: 0.81‒1.04, P = 0.160), regardless of hormone receptor expression levels. These data suggested the higher pCR rate in patients receiving ddNCT did not result in a survival benefit.

Conclusions

The meta-analysis demonstrated that ddNCT can significantly improve the pCR rate in patients with low hormone receptor expression levels, although patient survival was not significantly improved. The ddNCT can increase the breast-conserving rate and reduced pre-operative waiting time without increasing adverse reactions. This regimen can be considered when developing an NCT plan.

Neoadjuvant dose-dense chemotherapy for locally advanced breast cancer: a meta-analysis of published studies

Large operable or locally advanced breast cancers (BCs) are usually treated with neoadjuvant chemotherapy (CT) before surgery. However, there is no evidence to support an improvement in efficacy with dose-dense (DD) CT in this setting. We, therefore, carried out a meta-analysis to investigate whether DD-CT was more effective than the reference (every 3 weeks anthracyclines±taxanes) standard-dose CT as neoadjuvant treatment for BC. We searched Pubmed, SCOPUS, EMBASE, the Web of Science, CINAHL, and the Cochrane Central Register of Controlled Trials for randomized trials comparing conventional versus DD neoadjuvant CT for BC. Odds ratios (ORs) for pathologic complete responses (ypT0N0M0: pCR) and hazard ratios (HRs) of death and recurrence [overall survival (OS), and disease-free survival (DFS)] were estimated and pooled. A QUADAS-2 report for all studies included in the final analysis was tabulated for the risk of bias and applicability. A total of six randomized trials fulfilled the inclusion criteria. The pooled rates of the pCR were 13.5 and 9.2% in the experimental and control arms. A significant increase in the pCR [OR=1.55, 95% confidence interval (CI) 1.18-2.02, P=0.001] was noted with neoadjuvant DD-CT. However, the patients who received DD-CT did not have significantly better DFS and OS rates (DFS: HR=0.88, 95% CI 0.76-1.01, P=0.06; OS: HR=0.89, 95% CI 0.78-1.02, P=0.08). Even with the limitation of a relatively short follow-up period, this meta-analysis shows that DD neoadjuvant CT, despite not leading to a significant increase in survival, increases by 46.7% the possibility of achieving a pCR in operable and locally advanced BC. This treatment should thus be considered one of the backbone treatments of choice when neoadjuvant therapy is planned.

Recommendations for the Use of WBC Growth Factors: American Society of Clinical Oncology Clinical Practice Guideline Update

PURPOSE

To update the 2006 American Society of Clinical Oncology guideline on the use of hematopoietic colony-stimulating factors (CSFs).

METHODS

The American Society of Clinical Oncology convened an Update Committee and conducted a systematic review of randomized clinical trials, meta-analyses, and systematic reviews from October 2005 through September 2014. Guideline recommendations were based on the review of the evidence by the Update Committee.

RESULTS

Changes to previous recommendations include the addition of tbo-filgrastim and filgrastim-sndz, moderation of the recommendation regarding routine use of CSFs in older patients with diffuse aggressive lymphoma, and addition of recommendations against routine dose-dense chemotherapy in lymphoma and in favor of high-dose-intensity chemotherapy in urothelial cancer. The Update Committee did not address recommendations regarding use of CSFs in acute myeloid leukemia or myelodysplastic syndromes in adults.

RECOMMENDATIONS

Prophylactic use of CSFs to reduce the risk of febrile neutropenia is warranted when the risk of febrile neutropenia is approximately 20% or higher and no other equally effective and safe regimen that does not require CSFs is available. Primary prophylaxis is recommended for the prevention of febrile neutropenia in patients who are at high risk on the basis of age, medical history, disease characteristics, and myelotoxicity of the chemotherapy regimen. Dose-dense regimens that require CSFs should only be used within an appropriately designed clinical trial or if supported by convincing efficacy data. Current recommendations for the management of patients exposed to lethal doses of total-body radiotherapy, but not doses high enough to lead to certain death as a result of injury to other organs, include the prompt administration of CSFs.

Mithramycin A sensitizes therapy-resistant breast cancer stem cells toward genotoxic drug doxorubicin

Chemotherapy resistance is a major clinical challenge for the management of locally advanced breast cancer. Accumulating evidence suggests a major role of cancer stem cells (CSCs) in chemoresistance evoking the requirement of drugs that selectively target CSCs in combination with chemotherapy. Here, we report that mithramycin A, a known specificity protein (Sp)1 inhibitor, sensitizes breast CSCs (bCSCs) by perturbing the expression of drug efflux transporters, ATP-binding cassette sub-family G, member 2 (ABCG2) and ATP-binding cassette sub-family C, member 1 (ABCC1), survival factors, B-cell lymphoma 2 (Bcl-2) and X-linked inhibitor of apoptosis (XIAP), and, stemness regulators, octamer-binding transcription factor 4 (Oct4) and Nanog, which are inherently upregulated in these cells compared with the rest of the tumor population. In-depth analysis revealed that aberrant overexpression of Sp1 in bCSCs transcriptionally upregulates (1) resistance-promoting genes to protect these cells from genotoxic therapy, and (2) stemness regulators to sustain self-renewal potential of these cells. However, mithramycin A causes transcriptional suppression of these chemoresistant and self-renewal genes by inhibiting Sp1 recruitment to their promoters. Under such antisurvival microenvironment, chemotherapeutic agent doxorubicin induces apoptosis in bCSCs via DNA damage-induced reactive oxygen species generation. Cumulatively, our findings raise the possibility that mithramycin A might emerge as a promising drug in combinatorial therapy with the existing chemotherapeutic agents that fail to eliminate CSCs. This will consequently lead to the improvement of therapeutic outcome for the treatment-resistant breast carcinomas.

A Canadian national expert consensus on neoadjuvant therapy for breast cancer: linking practice to evidence and beyond

BACKGROUND

Use of the neoadjuvant approach to treat breast cancer patients has increased since the early 2000s, but the overall pathway of care for such patients can be highly variable. The aim of our project was to establish a multidisciplinary consensus among clinicians with expertise in neoadjuvant therapy (nat) for breast cancer and to determine if that consensus reflects published methods used in randomized controlled trials (rcts) in this area.

METHODS

A modified Delphi protocol, which used iterative surveys administered to 85 experts across Canada, was established to obtain expert consensus concerning all aspects of the care pathway for patients undergoing nat for breast cancer. All rcts published between January 1, 1967, and December 1, 2012, were systematically reviewed. Data extracted from the rcts were analyzed to determine if the methods used matched the expert consensus for specific areas of nat management. A scoring system determined the strength of the agreement between the literature and the expert consensus.

RESULTS

Consensus was achieved for all areas of the pathway of care for patients undergoing nat for breast cancer, with the exception of the role of magnetic resonance imaging in the pre-treatment or preoperative setting. The levels of agreement between the consensus statements and the published rcts varied, primarily because specific aspects of the pathway of care were not well described in the reviewed literature.

CONCLUSIONS

A true consensus of expert opinion concerning the pathway of care appropriate for patients receiving nat for breast cancer has been achieved. A review of the literature illuminated gaps in the evidence about some elements of nat management. Where evidence is available, agreement with expert opinion is strong overall. Our study is unique in its approach to establishing consensus among medical experts in this field and has established a pathway of care that can be applied in practice for patients receiving nat.

Pathologic complete response as a potential surrogate for the clinical outcome in patients with breast cancer after neoadjuvant therapy: a meta-regression of 29 randomized prospective studies

PURPOSE

To assess the role of pathologic complete response (pCR) after neoadjuvant therapy as surrogate end point of disease-free survival (DFS) and overall survival (OS) in patients with breast cancer, we performed a trial-based meta-regression of randomized studies comparing different neoadjuvant systemic treatments.

METHODS

The systematic literature search included electronic databases and proceedings of oncologic meetings. Endocrine therapy trials were excluded. Treatment effects on DFS and OS were expressed as hazard ratios (HRs), and treatment effects on pCR were expressed as odds ratios (ORs). A weighted regression analysis was performed on log-transformed treatment effect estimates to test the association between treatment effects on the surrogate outcome and treatment effects on the clinical outcome.

RESULTS

Twenty-nine trials, 59 arms, and 30 comparisons, for a total of 14,641 patients, were included in the analysis. Using the complete set of data, the regression of either the log(HR) for DFS or the log(HR) for OS on the log(OR) for pCR demonstrated only weak associations (R(2) = 0.08; 95% CI, 0 to 0.47; and R(2) = 0.09; 95% CI, 0.01 to 0.41, respectively). Better associations were found in an exploratory analysis assessing a subset of trials comparing intensified/dose-dense chemotherapy versus standard-dose regimens (DFS: R(2) = 0.79; 95% CI, 0.26 to 0.95; P = .003; and OS: R(2) = 0.57; 95% CI, 0.19 to 0.93; P = .03).

CONCLUSION

This meta-regression analysis of 29 heterogeneous neoadjuvant trials does not support the use of pCR as a surrogate end point for DFS and OS in patients with breast cancer. However, pCR may potentially meet the criteria of surrogacy with specific systemic therapies.

Surgical treatment of primary breast cancer in the neoadjuvant setting

Background

Neoadjuvant chemotherapy (NACT) is a standard treatment option for primary operable breast cancer when adjuvant chemotherapy is indicated.

Methods

This article reviews the use of NACT in breast cancer treatment.

Results

Pathological complete response (pCR) rates of up to 60 per cent have been reached for certain breast cancer subgroups. Patients achieving a pCR have a lower locoregional recurrence rate. Nevertheless, the rate of breast-conserving surgery seems to be stable at around 65–70 per cent, although more than 80 per cent of patients respond to NACT. The risk of local relapse does not appear to be higher after NACT, which supports the recommendation to operate within the new margins, as long as there is no tumour in the inked area of the surgical specimen. However, tumours do not shrink concentrically and the re-excision rate is higher after NACT. Mastectomy rates for lobular carcinomas remain high irrespective of tumour response. The role of sentinel lymph node biopsy (SLNB) in the context of NACT has been studied in recent years, and it is not yet completely clear which type of axillary staging is the most suitable. SLNB before NACT in clinically node-negative patients has been the preferred option. However, this practice is currently changing, and it seems advisable to have the SLNB after NACT to reduce the risk of a false-negative SLNB.

Conclusion

Overall, patients do benefit from NACT, especially those with human epidermal growth factor receptor 2-positive and triple-negative breast cancer, but surgical/local procedures need to be adapted.

Identification and validation of an anthracycline/cyclophosphamide-based chemotherapy response assay in breast cancer

Background

There is no method routinely used to predict response to anthracycline and cyclophosphamide–based chemotherapy in the clinic; therefore patients often receive treatment for breast cancer with no benefit. Loss of the Fanconi anemia/BRCA (FA/BRCA) DNA damage response (DDR) pathway occurs in approximately 25% of breast cancer patients through several mechanisms and results in sensitization to DNA-damaging agents. The aim of this study was to develop an assay to detect DDR-deficient tumors associated with loss of the FA/BRCA pathway, for the purpose of treatment selection.

Methods

DNA microarray data from 21 FA patients and 11 control subjects were analyzed to identify genetic processes associated with a deficiency in DDR. Unsupervised hierarchical clustering was then performed using 60 BRCA1/2 mutant and 47 sporadic tumor samples, and a molecular subgroup was identified that was defined by the molecular processes represented within FA patients. A 44-gene microarray-based assay (the DDR deficiency assay) was developed to prospectively identify this subgroup from formalin-fixed, paraffin-embedded samples. All statistical tests were two-sided.

Results

In a publicly available independent cohort of 203 patients, the assay predicted complete pathologic response vs residual disease after neoadjuvant DNA-damaging chemotherapy (5-fluorouracil, anthracycline, and cyclophosphamide) with an odds ratio of 3.96 (95% confidence interval [Cl] =1.67 to 9.41; P = .002). In a new independent cohort of 191 breast cancer patients treated with adjuvant 5-fluorouracil, epirubicin, and cyclophosphamide, a positive assay result predicted 5-year relapse-free survival with a hazard ratio of 0.37 (95% Cl = 0.15 to 0.88; P = .03) compared with the assay negative population.

Conclusions

A formalin-fixed, paraffin-embedded tissue-based assay has been developed and independently validated as a predictor of response and prognosis after anthracycline/cyclophosphamide–based chemotherapy in the neoadjuvant and adjuvant settings. These findings warrant further validation in a prospective clinical study.

Neoadjuvant chemotherapy and targeted therapy in breast cancer: past, present, and future

Traditionally, neoadjuvant treatment for breast cancer was preserved for locally advanced and inflammatory disease, converting an inoperable to a surgical resectable cancer. In recent years, neoadjuvant therapy has become an accepted treatment option also for lower tumor stages in order to increase the rate of breast conserving therapy and to reduce the extent of surgery. Furthermore, treatment response can be monitored, and therefore, patient compliance may be increased. Neoadjuvant trials, additionally, offer the opportunity to evaluate new treatment options in a faster way and with fewer patients than large adjuvant trials. Compared to the metastatic setting, the issue of acquired resistance and pretreatments, which may distort treatment efficacy, can be avoided. New trial designs like window-of-opportunity trials or postneoadjuvant trials provide the chance to identify tumor sensitivity or to overcome tumor resistance in early tumor stages. In particular, in HER2-positive breast cancer, the neoadjuvant approach yielded great successes. The dual HER2 blockade with trastuzumab and pertuzumab recently showed the highest pCR rates ever reported. Many new drugs are in clinical testing with the aim to further increase pCR rates. Whether this endpoint really represents a surrogate for long-term outcome is not answered yet and will be discussed in this review.

Neoadjuvant treatment of breast cancer

Neoadjuvant treatment of breast cancer has become established as the safe and often effective therapeutic approach of choice for larger primary and for locally advanced breast cancer. The neoadjuvant approach offers the advantages of downstaging the disease, potentially reducing the extent of surgery and in an era of individualization of therapy, testing the efficacy of therapy administered to patients. The preoperative setting is also an effective way to study the activity of novel agents or therapeutic combinations in vivo against human breast cancer. For new therapies, preoperative trials avoid the issue of adaptive resistance and pretreatments that can be problematic in the advanced disease setting. For evidence of a drug targeting the cancer in vivo, comparisons of endocrine therapy, chemotherapy agents and/or targeted agents can provide data on activity and efficacy with a much shorter time frame and many fewer patients than for adjuvant trials; effects seen in neoadjuvant trials may even reflect what is found in the adjuvant setting. Patient benefits from the neoadjuvant approach may be greatest for those who experience complete pathologically documented response (and the consequent survival benefits) and women for whom breast conservation, rather than mastectomy, becomes possible.

Gene expression and pathologic response to neoadjuvant chemotherapy in breast cancer

Pathologic complete response after neoadjuvant systemic treatment appears to be a valid surrogate for better overall survival in breast cancer patients. Currently, together with standard clinicopathologic assessment, novel molecular biomarkers are being exhaustively tested in order to look into the heterogeneity of breast cancer. The aim of our study was to examine an association between 23-gene real-time-PCR expression assay including ABCB1, ABCC1, BAX, BBC3, BCL2, CASP3, CYP2D6, ERCC1, FOXC1, GAPDH, IGF1R, IRF1, MAP2, MAPK 8, MAPK9, MKI67, MMP9, NCOA3, PARP1, PIK3CA, TGFB3, TOP2A, and YWHAZ receptor status of breast cancer core biopsies sampled before neoadjuvant chemotherapy (anthracycline and taxanes) and pathologic response. Core-needle biopsies were collected from 42 female patients with inoperable locally advanced breast cancer or resectable tumors suitable for downstaging, before any treatment. Expressions of 23 genes were determined by means of TagMan low density arrays. Analysis of variance was used to select genes with discriminatory potential between receptor subtypes. We introduced a correction for false discovery rates (presented as q values) due to multiple hypothesis testing. Statistical analysis showed that seven genes out of a 23-gene real-time-PCR expression assay differed significantly in relation to pathologic response regardless of breast cancer subtypes. Among these genes, we identified: BAX (p = 0.0146), CYP2D6 (p = 0.0063), ERCC1 (p = 0.0231), FOXC1 (p = 0.0048), IRF1 (p = 0.0022), MAP2 (p = 0.0011), and MKI67 (p = 0.0332). The assessment of core biopsy gene profiles and receptor-based subtypes, before neoadjuvant therapy seems to predict response or resistance and to define new signaling pathways to provide more powerful classifiers in breast cancer, hence the need for further research.