Skeletal metastases from breast cancer: pathogenesis of bone tropism and treatment strategy

Value of CT-based radiomics in evaluating the response of bone metastases to systemic drug therapy in breast cancer patients

BACKGROUND

This study aimed to investigate the value of nonenhanced computed tomography (CT)-based radiomics in determining disease progression in breast cancer patients with bone marrow metastases and to develop a model for assessing treatment efficacy.

METHODS

A total of 134 breast cancer patients with bone metastases were enrolled from three hospitals. Nonenhanced CT was performed after two cycles of drug treatment. The images were categorized into an invalid and a valid group according to disease progression status. The largest osteolytic lesions' maximum cross-sections in the CT images were selected as regions of interest (ROIs) for feature extraction. Variance threshold, SelectKBest, and least absolute shrinkage and selection operator (LASSO) were used to reduce feature dimensionality. K-nearest neighbor algorithm (KNN), support vector machine (SVM), extreme gradient boosting (XGBoost), random forest (RF), logistic regression (LR), and decision tree (DT) algorithms were trained to establish radiomics models. Receiver operating characteristic (ROC) curves were generated to evaluate the diagnostic performance of the models.

RESULTS

The KNN classifier demonstrated the best performance compared to the random grouping method. In the validation group, the area under the ROC curve (AUC) was 0.810. In the cross-validation method, the RF classifier showed the best performance with an AUC of 0.84.

CONCLUSION

Nonenhanced CT-based radiomics provides a promising method for evaluating the efficacy of systemic drug therapy in breast cancer patients with osteolytic bone metastases.

Functional anti-bone tumor biomaterial scaffold: construction and application

Bone tumors, including primary bone tumors and bone metastases, have been plagued by poor prognosis for decades. Although most tumor tissue is removed, clinicians are still confronted with the dilemma of eliminating residual cancer cells and regenerating defective bone tissue after surgery. Therefore, functional biomaterial scaffolds are considered to be the ideal candidates to bridge defective tissues and restrain cancer recurrence. Through functionalized structural modifications or coupled therapeutic agents, they provide sufficient mechanical strength and osteoinductive effects while eliminating cancer cells. Numerous novel approaches such as photodynamic, photothermal, drug-conjugated, and immune adjuvant-assisted therapies have exhibited remarkable efficacy against tumors while exhibiting low immunogenicity. This review summarizes the progress of research on biomaterial scaffolds based on different functionalization strategies in bone tumors. We also discuss the feasibility and advantages of the combined application of multiple functionalization strategies. Finally, potential obstacles to the clinical translation of anti-tumor bone bioscaffolds are highlighted. This review will provide valuable references for future advanced biomaterial scaffold design and clinical bone tumor therapy.

How to Target Spinal Metastasis in Experimental Research: An Overview of Currently Used Experimental Mouse Models and Future Prospects

The spine is one of the organs that is most affected by metastasis in cancer patients. Since the control of primary tumor is continuously improving, treatment of metastases is becoming one of the major challenges to prevent cancer-related death. Due to the anatomical proximity to the spinal cord, local spread of metastasis can directly cause neurological deficits, severely limiting the patient’s quality of life. To investigate the underlying mechanisms and to develop new therapies, preclinical models are required which represent the complexity of the multistep cascade of metastasis. Current research of metastasis focuses on the formation of the premetastatic niche, tumor cell dormancy and the influence and regulating function of the immune system. To unveil whether these influence the organotropism to the spine, spinal models are irreplaceable. Mouse models are one of the most suitable models in oncologic research. Therefore, this review provides an overview of currently used mouse models of spinal metastasis. Furthermore, it discusses technical aspects clarifying to what extend these models can picture key steps of the metastatic process. Finally, it addresses proposals to develop better mouse models in the future and could serve as both basis and stimulus for researchers and clinicians working in this field.

Tamoxifen Rechallenge Decreases Metastatic Potential but Increases Cell Viability and Clonogenicity in a Tamoxifen-Mediated Cytotoxicity-Resistant Subline of Human Breast MCF7 Cancer Cells

Background

Drug resistance is frequently found in estrogen receptor-positive (ER⁺) breast cancer patients during and after prolonged tamoxifen treatment. Although tamoxifen rechallenge has been proposed for treating recurrent breast tumors, the clinical benefit of this treatment is still controversial. The aims of this study are to identify the possible tamoxifen cytotoxicity-resistant subpopulation of MCF7 cells and to determine the effects of tamoxifen rechallenge on these cells.

Methods

Western blot analysis was used to determine the expression levels of various epithelial-mesenchymal transition- and cell survival/proliferation-related proteins in MCF7 and MCF7-derived, tamoxifen-mediated cytotoxicity-resistant MCF7-TAM12.5 breast cancer cells. Wound healing, Transwell migration, and invasion assays were used to examine the metastatic potential of cells. Clonogenic assays, trypan blue exclusion assays, and bromodeoxyuridine assays were used to examine clonogenicity and to determine the proliferation rate of cells.

Results

We found that MCF7-TAM12.5 cells exhibited higher tolerance to tamoxifen-mediated cytotoxicity, higher metastatic potential, higher expression levels of XIAP, and lower expression levels of ERα/ERβ/HER2/Smac than MCF7 cells. In addition, MCF7 cells endogenously expressed Bcl-2α, whereas MCF7-TAM12.5 cells only expressed Bcl-2β. Interestingly, tamoxifen rechallenge decreased the metastatic potential but increased the proliferation and clonogenicity of MCF7-TAM12.5 cells. At the molecular level, tamoxifen rechallenge upregulated the expression of phosphorylated Aurora A and Aurora B kinase in MCF7-TAM12.5 cells.

Conclusion

Our findings further support the existence of highly heterogenetic cancer cell populations in ER⁺ breast tumors. It will be of clinical importance to determine the protein expression and the genetic profiles of tamoxifen-resistant/recurrent ER⁺ breast tumors to predict the potential effects of tamoxifen readministration in the future.

Mechanically stimulated osteocytes reduce the bone-metastatic potential of breast cancer cells in vitro by signaling through endothelial cells

Bone metastases occur in 65% to 75% of patients with advanced breast cancer and significantly worsen their survival and quality of life. We previously showed that conditioned medium (CM) from osteocytes stimulated with oscillatory fluid flow, mimicking bone mechanical loading during routine physical activities, reduced the transendothelial migration of breast cancer cells. Endothelial cells are situated at an ideal location to mediate signals between osteocytes in the bone matrix and metastasizing cancer cells in the blood vessels. In this study, we investigated the specific effects of flow-stimulated osteocytes on the interaction between endothelial cells and breast cancer cells in vitro. We observed that CM from flow-stimulated osteocytes reduced endothelial permeability by 15% and breast cancer cell adhesion onto endothelial monolayers by 18%. The difference in adhesion was abolished with anti-intercellular adhesion molecule 1 (ICAM-1) neutralizing antibodies. Furthermore, CM from endothelial cells conditioned in CM from flow-stimulated osteocytes significantly altered the gene expression in bone-metastatic breast cancer cells, as shown by RNA sequencing. Specifically, breast cancer cell expression of matrix metallopeptidase 9 (MMP-9) was downregulated by 62%, and frizzled-4 (FZD4) by 61%, when the osteocytes were stimulated with flow. The invasion of these breast cancer cells across Matrigel was also reduced by 47%, and this difference was abolished by MMP-9 inhibitors. In conclusion, we demonstrated that flow-stimulated osteocytes downregulate the bone-metastatic potential of breast cancer cells by signaling through endothelial cells. This provides insights into the capability of bone mechanical regulation in preventing bone metastases; and may assist in prescribing exercise or bone-loading regimens to patients with breast cancers.

A rare case of cancer-to-cancer metastasis: breast cancer to renal cell cancer : Case report and review of literature

Background

Cancer-to-cancer metastasis is very rare with less than 50 cases described in literature. This article reports a case of breast cancer with synchronous metastasis to clear cell renal cell cancer.

Case description

A 79-year-old woman was diagnosed with a bilateral breast carcinoma. Sonographic staging investigation of the abdomen revealed a 6 cm wide expansion of the right kidney. Bilateral mastectomy and nephrectomy of the right kidney was performed. The histology revealed a clear cell renal cell carcinoma and in the center of the tumor a 0.5 cm metastasis of the breast cancer. The patient’s comorbidities and performance status precluded chemotherapy und she received palliative radiotherapy, targeted monoclonal antibody therapy and antihormonal treatment.

Conclusions

Even if cancer-to-cancer metastasis is a very rare phenomenon, the simultaneous or consecutive finding of a renal tumor in women with breast cancer should be carefully evaluated.

Pain prevalence and treatment in patients with metastatic bone disease

The accomplishment of successful pain treatment requires evaluation, characterization and quantification. The present study characterized pain and survival in a cohort of patients with cancer with bone metastasis who were treated with intravenous bisphosphonates. A total of 84 patients self-completed the Brief Pain Inventory (BPI) and 36-Item Short Form Survey (SF-36), between November 2010 and March 2011 with a 5-year survival follow-up as a surrogate marker of cancer burden. The median age was 62 years old (34–85), 64% of patients were female and 58% of these females had breast cancer. In the population, self-reported pain was 91.6%, with 29 patients (34.5%) reporting severe pain (score 7–10). Among these patients, only 13 (44.8%) presented a similar report to that of their clinical files and 5 were undergoing treatment with strong opioids (17.2%). A total of 45 patients (46%) had not been prescribed analgesic drugs, of these patients, 32 were treated with a weak opioid, and 13 with a strong opioid. An association was observed between pain records and the prescribed analgesic (P=0.031). BPI maximum pain and overall survival data were analyzed, and a significant association was identified between male patients presenting severe pain and decreased survival (P=0.004). Male survival was associated with severe pain, which is consistent with other data. The results revealed a skeletal-related events (SRE)-free survival (time elapsed from diagnosis of the first bone metastasis to the first SRE) of 9 months (4.39–13.73, 95% CI) with a statistically significant difference between subgroups of time since diagnosis of bone metastasis (P=0.005). The added value of the present study is the suggestion that complete and accurate pain narratives are mandatory and may contribute to the optimization of analgesia, and may help to increase survival rates. Optimal pain management for patients with cancer remains an urgent requirement.

Oncolytic Adenovirus rAd.DCN Inhibits Breast Tumor Growth and Lung Metastasis in an Immune-Competent Orthotopic Xenograft Model

The majority of advanced breast cancer patients develop distal metastasis, including lung and bone metastasis. However, effective therapeutic strategies to prevent metastasis are still lacking. Decorin is a natural inhibitor of transforming growth factor β, which plays a pivotal role in tumor metastasis. An oncolytic adenovirus expressing decorin, rAd.DCN, has been developed previously. In an immune-competent breast tumor (4T1) model, intratumoral (i.t.) as well as intravenous (i.v.) delivery of rAd.DCN inhibited growth of orthotopic tumors and spontaneous lung metastasis. It was shown that i.t. delivery of rAd.DCN produced higher levels of transgene expression and evoked stronger oncolysis of the tumors compared to i.v. delivery. However, i.v. delivery resulted in higher amount of virus accumulation in the lungs and produced stronger responses to prevent tumor lung metastasis. Oncolytic adenovirus-mediated decorin expression in the tumors downregulated the decorin target genes and decreased epithelial mesenchymal transition markers. Decorin expression in lung tissues also increased Th1 cytokine expression, such as interleukin (IL)-2, IL-12, and tumor necrosis factor α, and decreased Th2 cytokines, such as transforming growth factor β and IL-6. Moreover, rAd.DCN treatment induced strong systemic inflammatory responses and upregulated CD8⁺ T lymphocytes. In conclusion, rAd.DCN inhibits tumor growth and lung metastasis of breast cancer via regulating wnt/β-catenin, vascular endothelial growth factor (VEGF), and Met pathways, and modulating the antitumor inflammatory and immune responses. Considering that i.v. delivery was much more effective in preventing lung metastasis, systemic delivery of rAd.DCN might be a promising strategy to treat breast cancer lung metastasis.

Targeting the Metastatic Bone Microenvironment by MicroRNAs

Bone metastases are a common and devastating feature of late-stage breast cancer. Metastatic bone disease is a consequence of disturbed bone remodeling due to pathological interactions between cancer cells and the bone microenvironment (BME). In the BME, breast cancer cells severely alter the balanced bone formation and bone resorption driven by osteoblasts and osteoclasts. The complex cellular cross talk in the BME is governed by secreted molecules, signaling pathways and epigenetic cues including non-coding RNAs. MicroRNAs (miRNAs) are small non-coding RNAs that reduce protein abundance and regulate several biological processes, including bone remodeling. Under pathological conditions, abnormal miRNA signaling contributes to the progression of diseases, such as bone metastasis. Recently miRNAs have been demonstrated to regulate several key drivers of bone metastasis. Furthermore, miRNAs are implicated as important regulators of cellular interactions within the metastatic BME. As a consequence, targeting the BME by miRNA delivery or antagonism has been reported to limit disease progression in experimental and preclinical conditions positioning miRNAs as emerging novel therapeutic tools in metastatic bone disease. This review will summarize our current understanding on the composition and function of the metastatic BME and discuss the recent advances how miRNAs can modulate pathological interactions in the bone environment.

Co-delivery of dihydroartemisinin and docetaxel in pH-sensitive nanoparticles for treating metastatic breast cancerviathe NF-κB/MMP-2 signal pathway

Metastasis is a major barrier in cancer chemotherapy. Prolonged circulation and rapid, specific intracellular drug release are two main goals in the development of nanoscale drug delivery systems to treat metastatic breast cancer. In this study, we investigated the anti-metastasis effect of docetaxel (DTX) in combination with dihydroartemisinin (DHA) in metastatic breast cancer 4T1 cells. We synthesized a pH-sensitive material 4-arm-PEG-DTX with a hydrazone bond and used it to construct nanoparticles that co-deliver DTX and DHA (D/D NPs). The D/D NPs had a mean size of 142.5 nm and approximately neutral zeta potential. The pH-sensitive nanoparticles allowed acid-triggered drug release at the tumor site, showing excellent cytotoxicity (IC50 = 7.0 μg mL⁻¹), cell cycle arrest and suppression of cell migration and invasion. The mechanisms underlying the anti-metastasis effect of the D/D NPs involved downregulation of the expression of p-AKT, NF-κB and MMP-2. Therefore, D/D NPs represent a new nanoscale drug delivery system for treating metastatic breast cancer, responding to the acidic tumor microenvironment to release the chemotherapeutic drugs.

Co-delivery DTX and DHA as acid-sensitive nanoparticles to exert synergistic effects for metastatic breast cancer therapy.

Pain and quality of life in breast cancer patients

OBJECTIVE

To evaluate the influence of pain on quality of life in breast cancer patients.

METHODS

A cross-sectional study of 400 patients, including 118 without metastasis, 160 with loco-regional metastasis and 122 with distant metastasis. The instruments used were the European Organization for Research and Treatment for Cancer Quality of Life Questionnaire-Core 30 and the Breast Cancer-specific 23 and short McGill Pain Questionnaire.

RESULTS

In total, 71.7% of patients reported pain. The most frequent sensory descriptor used by patients was 'jumping.' In the evaluative dimension, the main descriptor chosen was troublesome. The Global Health self-assessment showed pain to be inversely correlated with quality of life: the group without metastasis had a mean score of 55.3 (SD=24.8) for those in pain, which rose to 69.7 (SD=19.2) for those without pain (p=0.001). Subjects with loco-regional metastasis had score of 59.1 (SD=21.3) when in pain, and those without pain had a significantly higher score of 72.4 (SD=18.6) (p<0.001). Patients from the distant metastasis group showed similar results with a mean score of 48.6 (SD=23.1) for those in pain and 67.6 (SD=20.4) for those without pain (p=0.002). Regarding the association of pain intensity and quality of life, patients with distant metastasis and intense pain had the worst scores for quality of life with a functional scale mean of 49.9 (SD=17.3) (p<0.009), a Symptom Scale score of 50.0 (SD=20.1) (p<0.001) and a Global Health Scale score of 39.7 (SD=24.7) (p<0.006).

CONCLUSIONS

Pain compromises the quality of life of patients with breast cancer, particularly those with advanced stages of the disease.

Label-free Raman spectroscopy provides early determination and precise localization of breast cancer-colonized bone alterations

Raman spectral markers offer new routes to recognition of biomolecular alterations at sites of nascent and progressing metastatic cancer in bone.

Breast neoplasms frequently colonize bone and induce development of osteolytic bone lesions by disrupting the homeostasis of the bone microenvironment. This degenerative process can lead to bone pain and pathological bone fracture, a major cause of cancer morbidity and diminished quality of life, which is exacerbated by our limited ability to monitor early metastatic disease in bone and assess fracture risk. Spurred by its label-free, real-time nature and its exquisite molecular specificity, we employed spontaneous Raman spectroscopy to assess and quantify early metastasis driven biochemical alterations to bone composition. As early as two weeks after intracardiac inoculations of MDA-MB-435 breast cancer cells in NOD-SCID mice, Raman spectroscopic measurements in the femur and spine revealed consistent changes in carbonate substitution, overall mineralization as well as crystallinity increase in tumor-bearing bones when compared with their normal counterparts. Our observations reveal the possibility of early stage detection of biochemical changes in the tumor-bearing bones – significantly before morphological variations are captured through radiographic diagnosis. This study paves the way for a better molecular understanding of altered bone remodeling in such metastatic niches, and for further clinical studies with the goal of establishing a non-invasive tool for early metastasis detection and prediction of pathological fracture risk in breast cancer.

Polyurethane foam scaffold as in vitro model for breast cancer bone metastasis

Breast cancer (BC) represents the most incident cancer case in women (29%), with high mortality rate. Bone metastasis occurs in 20-50% cases and, despite advances in BC research, the interactions between tumor cells and the metastatic microenvironment are still poorly understood. In vitro 3D models gained great interest in cancer research, thanks to the reproducibility, the 3D spatial cues and associated low costs, compared to in vivo and 2D in vitro models. In this study, we investigated the suitability of a poly-ether-urethane (PU) foam as 3D in vitro model to study the interactions between BC tumor-initiating cells and the bone microenvironment. PU foam open porosity (>70%) appeared suitable to mimic trabecular bone structure. The PU foam showed good mechanical properties under cyclic compression (E=69-109kPa), even if lower than human trabecular bone. The scaffold supported osteoblast SAOS-2 cell line proliferation, with no cytotoxic effects. Human adipose derived stem cells (ADSC) were cultured and differentiated into osteoblast lineage on the PU foam, as shown by alizarin red staining and RT-PCR, thus offering a bone biomimetic microenvironment to the further co-culture with BC derived tumor-initiating cells (MCFS). Tumor aggregates were observed after three weeks of co-culture by e-cadherin staining and SEM; modification in CaP distribution was identified by SEM-EDX and associated to the presence of tumor cells. In conclusion, we demonstrated the suitability of the PU foam to reproduce a bone biomimetic microenvironment, useful for the co-culture of human osteoblasts/BC tumor-initiating cells and to investigate their interaction.

STATEMENT OF SIGNIFICANCE

3D in vitro models represent an outstanding alternative in the study of tumor metastases development, compared to traditional 2D in vitro cultures, which oversimplify the 3D tissue microenvironment, and in vivo studies, affected by low reproducibility and ethical issues. Several scaffold-based 3D in vitro models have been proposed to recapitulate the development of metastases in different body sites but, still, the crucial challenge is to correctly mimic the tissue to be modelled in terms of physical, mechanical and biological properties. Here, we prove the suitability of a porous polyurethane foam, synthesized using an appropriate formulaton, in mimicking the bone tissue microenvironment and in reproducing the metastatic colonization derived from human breast cancer, particularly evidencing the devastating effects on the bone extracellular matrix caused by metastatic spreading.

Tumor angiogenesis and bone metastasis - Correlation in invasive breast carcinoma

PURPOSE

To test the hypotheses that pathological biomarkers including CD34 positive endothelial cell and microvessel density (MVD) of the primary breast tumor can be used to predict the probability of occurrence for bone metastases and provide information for appropriate therapeutic strategies at an early stage.

METHODS

Three groups of CD34 immunohistochemical stained slices (n=60) were acquired from surgical specimens of sixty patients including non-metastasis (group 1), only lymph node metastasis (group 2), and bone metastasis (group 3). MVD was measured by TissueGnostics system.

RESULTS

The MVD measurement results were 57.14±23.00 in group 1, 86.44±21.13 in group 2, and 126.85±47.89 in group 3. There were statistical differences between group 1 and group 2 (P=0.0002), between group 2 and group 3 (P=0.0014) and between group 1 and group 3 (P<0.0001). The strong correlations were found between CD34 positive cell measurement and its percentage (group 1, r=0.74, P=0.0002; group 2, r=0.62, P=0.0034; group 3, r=0.84, P<0.0001), and between CD34 positive endothelial cell measurement and MVD (r=0.61, P<0.0001).

CONCLUSIONS

Quantitative CD34 positive endothelial cell and MVD measurements of the primary breast tumor have a strong correlation with the occurrence rate of bone metastases, which predicts the probability of occurrence for bone metastases at an early stage.

Prevention of breast cancer skeletal metastases with parathyroid hormone

Advanced breast cancer is frequently associated with skeletal metastases and accelerated bone loss. Recombinant parathyroid hormone [teriparatide, PTH(1-34)] is the first anabolic agent approved in the US for treatment of osteoporosis. While signaling through the PTH receptor in the osteoblast lineage regulates bone marrow hematopoietic niches, the effects of anabolic PTH on the skeletal metastatic niche are unknown. Here, we demonstrate, using orthotopic and intratibial models of 4T1 murine and MDA-MB-231 human breast cancer tumors, that anabolic PTH decreases both tumor engraftment and the incidence of spontaneous skeletal metastasis in mice. Microcomputed tomography and histomorphometric analyses revealed that PTH increases bone volume and reduces tumor engraftment and volume. Transwell migration assays with murine and human breast cancer cells revealed that PTH alters the gene expression profile of the metastatic niche, in particular VCAM-1, to inhibit recruitment of cancer cells. While PTH did not affect growth or migration of the primary tumor, it elicited several changes in the tumor gene expression profile resulting in a less metastatic phenotype. In conclusion, PTH treatment in mice alters the bone microenvironment, resulting in decreased cancer cell engraftment, reduced incidence of metastases, preservation of bone microarchitecture and prolonged survival.

Estrogen receptors in breast and bone: from virtue of remodeling to vileness of metastasis

Bone metastasis is a prominent cause of morbidity and mortality in cancer. High rates of bone colonization in breast cancer, especially in the subtype expressing estrogen receptors (ERs), suggest tissue-specific proclivities for metastatic tumor formation. The mechanisms behind this subtype-specific organ-tropism remains largely elusive. Interestingly, as the major driver of ER+ breast cancer, ERs also have important roles in bone development and homeostasis. Thus, any agents targeting ER will also inevitably affect the microenvironment, which involves the osteoblasts and osteoclasts. Yet, how such microenvironmental effects are integrated with direct therapeutic responses of cancer cells remain poorly understood. Recent findings on ER mutations, especially their enrichment in bone metastasis, raised even more provocative questions on the role of ER in cancer-bone interaction. In this review, we evaluate the importance of ERs in bone metastasis and discuss new avenues of investigation for bone metastasis treatment based on current knowledge.

Adult-onset Still's disease-like manifestation accompanied by the cancer recurrence after long-term resting state

A 72-year-old woman presented 9 months ago with skin rash on her bilateral forearms, which was followed by intermittent high fever, and stiffness and swelling of her bilateral fingers. She was diagnosed with seronegative rheumatoid arthritis (RA). She had a past history of breast cancer and had undergone breast preservation surgery 13 years previously. During admission in our hospital, she developed high fever and leukocytosis with a relapsing skin rash, sore throat, polyarthralgia and increased levels of serum ALT/AST and ferritin, all of which fulfilled Yamaguchi's criteria for adult-onset Still's disease (AOSD). While we tried to exclude other diseases that may show AOSD-like manifestations, pancytopenia rapidly developed and bone marrow biopsy strongly suggested the diagnosis of macrophage activating syndrome (MAS). Accordingly, steroid pulse therapy was begun, followed by oral glucocorticoid therapy. Thereafter, all of her symptoms improved, but systemic rash, inflammatory signs and pancytopenia gradually progressed. The results of bone marrow pathology, which returned 2 weeks after the beginning of treatment, revealed hemophagocytosis with CK7-positive/CK20-negative atypical cells that suggested recurrence of breast cancer in the bone marrow, thus all of her AOSD-like symptoms were considered to be paraneoplastic manifestations of late-onset metastatic breast cancer. She was treated successfully with chemotherapy. When we see the patients showing AOSD-like symptoms with a history of malignancy, we should consider the possibility of paraneoplastic syndrome due to cancer recurrence.

Differentiating the Causes of Spontaneous Rib Fracture After Breast Cancer

Spontaneous rib fracture after treatment for primary breast cancer is not uncommon. Although metastatic disease accounts for about 30% of spontaneous rib fractures and should constitute the first line of diagnostic investigation, other possible contributors include primary osteoporosis or secondary osteoporosis resulting from cancer treatments. Chemotherapy-induced menopause, aromatase inhibitors, radiation therapy, and long-term bisphosphonate use can all contribute to bone fragility, including spontaneous rib fractures in the latter 3. Drawing on recent breast cancer practice guidelines as well as population-based studies of fracture risk for women with a history of breast cancer and systematic reviews, this Perspective will provide an update on recent developments in understanding how to differentiate the possible reasons for non-traumatic rib fracture in women treated for breast cancer. In addition to describing the various possible causes of spontaneous rib fracture, the recommended medical and imaging procedures for differentiating among the potential causes will be presented.

Management of Bone Metastases From Breast Cancer in Upper and Lower Body at the Same Time: A Case Report

Breast cancer is by far the most common cancer in women, and it has the highest incidence rates in western Europe. At breast cancer diagnosis, approximately 5-6% of women present with distant spread with bone, representing the most common site of metastatic lesions. More than half of the women, who present with metastatic breast cancer at the primary diagnosis, will develop bone metastases. We report a clinical case of a 75-year-old woman, with a history of breast cancer who undergone surgery 7 years ago, presenting bone metastases in different areas. We tried to determinate the major areas of pain and then to quantify it with a one-dimensional scale. After that, we analyzed the images of the previous instrumental exams and the centering CT in order to compare them with what the patient reported and then to decide what we should have targeted first. The aim of our work was to try finding a methodology in order to determinate the priority in the selecting of the area to treat to apply in this kind of patients.

Age-related differences in persistence with bisphosphonates in women with metastatic breast cancer

Aims

To investigate age-related persistence with bisphosphonates (BIS) in women with breast cancer (BC) and bone metastases.

Methods

We included a dataset of 1541 patients diagnosed with BC and bone metastases and initially treated with BIS between 1994 and 2013. The primary outcome measure was the age-related rate of BIS discontinuation within 12 months after treatment initiation. Therapy discontinuation was defined as a period of at least 90 days without treatment. A multivariate Cox regression model was created to determine the influence of age on the risk of discontinuation. Health insurance coverage (private/statutory), type of care (gynecological/general), region (West/East Germany), depression, chemotherapy, hormone therapy, pain medication, antidepressants, and the number of co-medications were included as covariates.

Results

The mean ages in the group of women <70 and that of women ≥70 years of age were 55.7 (SD: 9.8) and 76.7 (SD: 5.1) years respectively. Within 12 months after treatment initiation, 44.3% of women <70 and 34.8% of women ≥70 had terminated treatment (p-value<0.001). Patients aged ≥70 were at a lower risk of treatment discontinuation than patients <70 (HR=0.78, 95% CI: 0.67–0.91). Furthermore, treatment in gynecological practices, chemotherapy, hormone therapy, pain medication, and number of co-medications decreased the risk of discontinuation. By contrast, residing in West Germany and private health insurance coverage increased discontinuation risk.

Conclusions

Women with metastatic BC aged ≥70 are at a lower risk of BIS treatment discontinuation than younger women.

Systemic Delivery of an Oncolytic Adenovirus Expressing Decorin for the Treatment of Breast Cancer Bone Metastases

The development of novel therapies for breast cancer bone metastasis is a major unmet medical need. Toward that end, we have constructed an oncolytic adenovirus, Ad.dcn, and a nonreplicating adenovirus, Ad(E1-).dcn, both containing the human decorin gene. Our in vitro studies showed that Ad.dcn produced high levels of viral replication and the decorin protein in the breast tumor cells. Ad(E1-).dcn-mediated decorin expression in MDA-MB-231 cells downregulated the expression of Met, β-catenin, and vascular endothelial growth factor A, all of which are recognized decorin targets and play pivotal roles in the progression of breast tumor growth and metastasis. Adenoviral-mediated decorin expression inhibited cell migration and induced mitochondrial autophagy in MDA-MB-231 cells. Mice bearing MDA-MB-231-luc skeletal metastases were systemically administered with the viral vectors, and skeletal tumor growth was monitored over time. The results of bioluminescence imaging and X-ray radiography indicated that Ad.dcn and Ad(E1-).dcn significantly inhibited the progression of bone metastases. At the terminal time point, histomorphometric analysis, micro-computed tomography, and bone destruction biomarkers showed that Ad.dcn and Ad(E1-).dcn reduced tumor burden and inhibited bone destruction. A nonreplicating adenovirus Ad(E1-).luc expressing the luciferase 2 gene had no significant effect on inhibiting bone metastases, and in several assays, Ad.dcn and Ad(E1-).dcn were better than Ad.luc, a replicating virus expressing the luciferase 2 gene. Our data suggest that adenoviral replication coupled with decorin expression could produce effective antitumor responses in a MDA-MB-231 bone metastasis model of breast cancer. Thus, Ad.dcn could potentially be developed as a candidate gene therapy vector for treating breast cancer bone metastases.