The role of preoperative systemic treatment in patients with breast cancer

Optical Imaging of Glucose Uptake and Mitochondrial Membrane Potential to Characterize Her2 Breast Tumor Metabolic Phenotypes

With the large number of women diagnosed and treated for breast cancer each year, the importance of studying recurrence has become evident due to most deaths from breast cancer resulting from tumor recurrence following therapy. To mitigate this, cellular and molecular pathways used by residual disease prior to recurrence must be studied. An altered metabolism has long been considered a hallmark of cancer, and several recent studies have gone further to report metabolic dysfunction and alterations as key to understanding the underlying behavior of dormant and recurrent cancer cells. Our group has used two probes, 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl) amino]-2-deoxyglucose (2-NBDG) and tetramethyl rhodamine ethyl ester (TMRE), to image glucose uptake and mitochondrial membrane potential, respectively, to report changes in metabolism between primary tumors, regression, residual disease, and after regrowth in genetically engineered mouse (GEM)-derived mammospheres. Imaging revealed unique metabolic phenotypes across the stages of tumor development. Although primary mammospheres overexpressing Her2 maintained increased glucose uptake ("Warburg effect"), after Her2 downregulation, during regression and residual disease, mammospheres appeared to switch to oxidative phosphorylation. Interestingly, in mammospheres where Her2 overexpression was turned back on to model recurrence, glucose uptake was lowest, indicating a potential change in substrate preference following the reactivation of Her2, reeliciting growth. Our findings highlight the importance of imaging metabolic adaptions to gain insight into the fundamental behaviors of residual and recurrent disease. IMPLICATIONS: This study demonstrates these functional fluorescent probes' ability to report metabolic adaptations during primary tumor growth, regression, residual disease, and regrowth in Her2 breast tumors.

Survival benefit of neoadjuvant chemotherapy for resectable breast cancer: A meta-analysis

BACKGROUND

Neoadjuvant chemotherapy (NAC) increases breast conservation rates in patients with resectable breast cancer at the associated cost of higher locoregional recurrence rates; however, the magnitude of the survival benefits of NAC for these patients remains undefined. Therefore, we aimed to clarify the survival benefit of NAC versus postoperative chemotherapy by conducting an updated meta-analysis of randomized clinical trials (RCTs).

METHODS

The authors searched the Cochrane Library, PubMed, Embase, Web of Science, Chinese biomedical literature database, and Chinese Scientific Journals full-text database from their inception to December 2016. The authors identified relevant RCTs that compared NAC with postoperative chemotherapy in the treatment of operable breast cancer. The main endpoints were overall survival (OS) and recurrence-free survival (RFS).

RESULTS

A total of 21 citations representing 16 unique studies were eligible. There were 787 deaths among 2794 patients assigned to NAC groups and 816 deaths among 2799 patients assigned to adjuvant chemotherapy groups. A meta-analysis of data indicated that there was no significant benefit in terms of OS ([hazard ratio [HR] = 1.03, 95% confidence interval [CI]: 0.94-1.13, P = .51) and RFS (HR = 1.01, 95% CI: 0.93-1.10, P = .80) between the NAC and postoperative chemotherapy groups. The pooled HR estimate for OS was not influenced by NAC cycles, the total number of chemotherapy cycles, administration of tamoxifen, administration of adjuvant chemotherapy, or type of NAC regimen. Subgroup analysis showed that the pooled HR estimate for RFS was influenced by anthracycline-containing regimens. Patients with a pathological complete response had superior survival outcomes compared with patients who had residual disease.

CONCLUSION

The survival benefits for patients with operable breast cancer who received either NAC or adjuvant chemotherapy based on anthracycline regimens were comparable.