Should bisphosphonates be utilized in the adjuvant setting for breast cancer?

Risk factors, prognostic factors, and nomograms for bone metastasis in patients with newly diagnosed infiltrating duct carcinoma of the breast: a population-based study

Background

Breast cancer is the most common malignancy in women, and it is also the leading cause of death in female patients; the most common pathological type of BC is infiltrating duct carcinoma (IDC). Some nomograms have been developed to predict bone metastasis (BM) in patients with breast cancer. However, there are no studies on diagnostic and prognostic nomograms for BM in newly diagnosed IDC patients.

Methods

IDC patients with newly diagnosed BM from 2010 to 2016 in the Surveillance, Epidemiology and End Results (SEER) database were reviewed. Multivariate logistic regression analysis was used to identify risk factors for BM in patients with IDC. Univariate and multivariate Cox proportional hazards regression analysis were used to explore the prognostic factors of BM in patients with IDC. We then constructed nomograms to predict the risk and prognosis of BM for patients with IDC. The results were validated using bootstrap resampling and retrospective research on 113 IDC patients with BM from 2015 to 2018 at the Affiliated Hospital of Chengde Medical University.

Results

This study included 141,959 patients diagnosed with IDC in the SEER database, of whom 2383 cases were IDC patients with BM. The risk factors for BM in patients with IDC included sex, primary site, grade, T stage, N stage, liver metastasis, race, brain metastasis, breast cancer subtype, lung metastasis, insurance status, and marital status. The independent prognostic factors were brain metastases, race, grade, surgery, chemotherapy, age, liver metastases, breast cancer subtype, insurance status, and marital status. Through calibration, receiver operating characteristic curve and decision curve analyses, we found that the nomogram for predicting the prognosis of IDC patients with BM displayed great performance both internally and externally.

Conclusion

These nomograms are expected to be a precise and personalized tool for predicting the risk and prognosis for BM in patients with IDC. This will help clinicians develop more rational and effective treatment strategies.

Comparison of the clinicopathological characteristics and prognosis between Chinese patients with breast cancer with bone-only and non-bone-only metastasis

Bone is the most common site of metastatic spread in patients with breast cancer. Patients with bone-only metastasis (BOM) are a unique group. The aim of the present study was to compare the clinicopathological characteristics, survival and prognostic factors of patients with BOM and non-BOM. The clinical data of 1,290 patients with metastatic breast cancer treated at the Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) between January 2008 and December 2017 were reviewed. The clinical data were divided into a BOM group (n=208 cases) and a non-BOM group (n=1,082 cases). Patients with BOM had longer disease-free survival, progression-free survival (PFS) and overall survival (OS) compared with patients in the non-BOM group. The hormone receptor (HR) status and number of metastases were significant influencing factors of PFS in the BOM group. Furthermore, the HR status, location of bone metastasis and number of bone metastases were significantly associated with OS of patients in the BOM group. Age at diagnosis of metastasis, HR status and tumor stage were significantly associated with OS in the non-BOM group. In the BOM group, patients with HR⁺/human epidermal growth factor receptor 2 (HER2)⁻ tumors had the most favorable prognosis. In the non-BOM group, patients with HR⁺/HER2⁻ and HER2⁺ tumors had improved prognosis. In the BOM with HR⁺/HER2⁻ subgroup, the PFS and OS of patients receiving endocrine therapy or sequential therapy (chemotherapy followed by endocrine therapy) was significantly improved compared with those receiving chemotherapy alone (P<0.05). Skeletal-related events were significantly associated with the number of bone metastases (P<0.001). The most common secondary metastatic site in the BOM group was the liver. The prognosis of the patients in the BOM group was improved compared with that in the non-BOM patients. HR⁻ and multiple bone metastases, as well as combined axial and appendicular bone metastases, were significantly associated with poor prognosis in the patients with BOM. For patients in the HR⁺/HER2⁻ BOM subgroup, endocrine therapy alone resulted in satisfactory results.

Evaluation of clinical parameters influencing the development of bone metastasis in breast cancer

BACKGROUND

The development of metastases is a negative prognostic parameter for the clinical outcome of breast cancer. Bone constitutes the first site of distant metastases for many affected women. The purpose of this retrospective multicentre study was to evaluate if and how different variables such as primary tumour stage, biological and histological subtype, age at primary diagnosis, tumour size, the number of affected lymph nodes as well as grading influence the development of bone-only metastases.

METHODS

This retrospective German multicentre study is based on the BRENDA collective and included 9625 patients with primary breast cancer recruited from 1992 to 2008. In this analysis, we investigated a subgroup of 226 patients with bone-only metastases. Association between bone-only relapse and clinico-pathological risk factors was assessed in multivariate models using the tree-building algorithms "exhausted CHAID (Chi-square Automatic Interaction Detectors)" and CART(Classification and Regression Tree), as well as radial basis function networks (RBF-net), feedforward multilayer perceptron networks (MLP) and logistic regression.

RESULTS

Multivariate analysis demonstrated that breast cancer subtypes have the strongest influence on the development of bone-only metastases (χ2 = 28). 29.9 % of patients with luminal A or luminal B (ABC-patients) and 11.4 % with triple negative BC (TNBC) or HER2-overexpressing tumours had bone-only metastases (p < 0.001). Five different mathematical models confirmed this correlation. The second important risk factor is the age at primary diagnosis. Moreover, BC subcategories influence the overall survival from date of metastatic disease of patients with bone-only metastases. Patients with bone-only metastases and TNBC (p < 0.001; HR = 7.47 (95 % CI: 3.52-15.87) or HER2 overexpressing BC (p = 0.007; HR = 3.04 (95 % CI: 1.36-6.80) have the worst outcome compared to patients with luminal A or luminal B tumours and bone-only metastases.

CONCLUSION

The bottom line of different mathematical models is the prior importance of subcategories of breast cancer and the age at primary diagnosis for the appearance of osseous metastases. The primary tumour stage, histological subtype, tumour size, the number of affected lymph nodes, grading and NPI seem to have only a minor influence on the development of bone-only metastases.

Quetiapine inhibits osteoclastogenesis and prevents human breast cancer-induced bone loss through suppression of the RANKL-mediated MAPK and NF-κB signaling pathways

Bone loss is one of the major complications of advanced cancers such as breast cancer, prostate cancer, and lung cancer. Extensive research has revealed that the receptor activator of NF-κB ligand (RANKL), which is considered to be a key factor in osteoclast differentiation, plays an important role in cancer-associated bone resorption. Therefore, agents that can suppress this bone loss have therapeutic potential. In this study, we detected whether quetiapine (QUE), a commonly used atypical antipsychotic drug, can inhibit RANKL-induced osteoclast differentiation in vitro and prevent human breast cancer-induced bone loss in vivo. RAW 264.7 cells and bone marrow-derived macrophages (BMMs) were used to detect inhibitory effect of QUE on osteoclastogenesis in vitro. Mouse model of breast cancer metastasis to bone was used to test suppressive effect of QUE on breast cancer-induced bone loss in vivo. Our results show that QUE can inhibit RANKL-induced osteoclast differentiation from RAW 264.7 cells and BMMs without signs of cytotoxicity. Moreover, QUE reduced the occurrence of MDA-MB-231 cell-induced osteolytic bone loss by suppressing the differentiation of osteoclasts. Finally, molecular analysis revealed that it is by inhibiting RANKL-mediated MAPK and NF-κB signaling pathways that QUE suppressed the osteoclast differentiation. We demonstrate, for the first time, the novel suppressive effects of QUE on RANKL-induced osteoclast differentiation in vitro and human breast cancer-induced bone loss in vivo, suggesting that QUE may be a potential therapeutic drug for osteolysis treatment.

Molecular pathways: YAP and TAZ take center stage in organ growth and tumorigenesis

The evolution of a solid tumor is fueled by genetic aberrations. Yet, the tumor environment often dominates over the effects of genetics: normal tissues have powerful tumor-suppressive properties that constantly tame or eliminate cells carrying transforming mutations. Critical elements of such a suppressive microenvironment are structural characteristics of normal cells and tissues, such as cell polarity, attachment to the extracellular matrix (ECM), and epithelial organization. Once these tissue-level checkpoints have been overcome, tumor growth is enhanced by recruitment of stromal cells and remodeling of the ECM. Genetic inactivation in mouse models indicates the Hippo pathway as a fundamental inhibitor of organ growth during development and as a critical tumor suppressor in epithelial tissues, such as the liver, skin, and ovaries, and soft tissues. At the centerpiece of this pathway lie two related transcriptional coactivators, YAP and TAZ, that promote tissue proliferation and the self-renewal of normal and cancer stem cells, and incite metastasis. Strikingly, YAP and TAZ are controlled by the same architectural features that first inhibit and then foster cancer growth, such as ECM elasticity, cell shape, and epithelial-to-mesenchymal transition. These findings open unexpected opportunities for the development of new cancer therapeutics targeting key YAP/TAZ regulatory inputs such as Wnt signaling, cytoskeletal contractility, G-protein-coupled receptors, or YAP/TAZ-regulated transcription.

Aromatase inhibitors-induced bone loss in early breast cancer

Women with breast cancer have an increased prevalence and incidence of fractures. This increased risk of fracture has become most evident following the use of aromatase inhibitors (AIs) as standard adjuvant therapy. AI-induced bone loss occurs at more than twice the rate of physiologic postmenopausal bone loss. Moreover, peripheral quantitative computed tomography data indicate that effects of AIs on bone strength and on cortical bone have been substantially underestimated by dual-energy X-ray absorptiometry. All AIs have been associated with an increased fracture risk. The incidence of fractures is at least 33-43% higher in AI-treated patients than in tamoxifen-treated patients, and this increase in fracture risk is maintained at least for the duration of AI therapy. Over the last few years, clinical trials have established the effectiveness of bisphosphonates and denosumab to preserve and even increase bone mineral density (BMD) during adjuvant AIs. Most data have been obtained with zoledronic acid administered twice a year, which effectively maintains or increases BMD in women receiving AIs. In addition, zoledronic acid has been shown to delay disease recurrence and maybe prolong survival in women with hormone-responsive tumors, thereby providing an adjuvant antitumor benefit besides preserving BMD. It is likely that a combined fracture risk assessment will more accurately identify women with breast cancer who require bone protective therapy. The FRAX tool probably underestimates the net increase in fracture risk due to AI therapy. Recent guidelines for the prevention of AI-induced bone loss have adequately considered the presence of several established clinical risk factors for fractures, in addition to BMD, when selecting patients to be treated with inhibitors of bone resorption.

Antiresorptive therapies in oncology and their effects on cancer progression

Bone health is an emerging concern in the early breast cancer setting. Current adjuvant therapies, especially hormonal therapies in premenopausal patients (e.g. goserelin) and aromatase inhibitors in postmenopausal patients, have been associated with substantial decreases in bone mineral density that may place patients at risk for fractures. Bisphosphonates--and the recently approved anti-RANKL antibody, denosumab--have both demonstrated activity for the treatment of postmenopausal osteoporosis and cancer treatment-induced bone loss (CTIBL) in breast cancer patients, although neither has received widespread approval specifically for CTIBL. However, some bisphosphonates, especially the nitrogen-containing bisphosphonate zoledronic acid, have also demonstrated clinically meaningful anticancer effects in patients receiving adjuvant hormonal therapy for breast cancer and in other oncology settings. The effects of denosumab on cancer disease outcomes in the adjuvant setting remain to be established. This discrepancy has created a dilemma in terms of how to evaluate the complete benefit:risk profile of bone-health management options in the adjuvant breast cancer setting. This review summarises the current data on the course of cancer in clinical trials of the antiresorptive agents and provides important insight into the relative anticancer potential of the various therapies.

Bisphosphonates: prevention of bone metastases in breast cancer

Disease recurrence and distant metastases remain challenging for patients with breast cancer despite advances in early diagnosis, surgical expertise, and adjuvant therapy. Bone is the most common site for breast cancer metastasis, and the bone microenvironment plays a crucial role in harboring disseminated tumor cells (DTCs), a putative source of late relapse in and outside bone. Therefore, agents that affect bone metabolism might not only prevent the development of bone lesions but also provide meaningful reductions in the risk of relapse both in bone and beyond. Bisphosphonates bind to mineralized bone surfaces and are ingested by osteoclasts, wherein they inhibit osteolysis, thereby preventing the release of growth factors from the bone matrix. Therefore, the bone microenvironment becomes less conducive to survival and growth of DTCs and bone lesion formation. Recent trials of zoledronic acid in the adjuvant setting in breast cancer have demonstrated reduced disease recurrence in bone and other sites in premenopausal and postmenopausal women with early breast cancer. Based on the proven effect of bone protection during adjuvant endocrine therapy, new treatment guidelines recommend the routine use of bisphosphonates to prevent bone loss during adjuvant therapy, which may likely become the standard practice.

Increased fracture rate in women with breast cancer: a review of the hidden risk

Background

Women with breast cancer, particularly individuals diagnosed at a relatively early age, have an increased incidence of fractures. Fractures can have serious clinical consequences including the need for major surgery, increased morbidity and mortality, increased cost of disease management, and reduced quality of life for patients. The primary cause of the increased fracture risk appears to be an accelerated decrease in bone mineral density (BMD) resulting from the loss of estrogenic signaling that occurs with most treatments for breast cancer, including aromatase inhibitors. However, factors other than BMD levels alone may influence treatment decisions to reduce fracture risk in this setting. Our purpose is to review current evidence for BMD loss and fracture risk during treatment for breast cancer and discuss pharmacologic means to reduce this risk.

Results

Fracture risk during treatment for breast cancer may be influenced by the rate of BMD loss and the consequent rapid alterations in bone microarchitecture, in addition to the established fracture risk factors in postmenopausal osteoporosis. The rapid decrease in BMD during adjuvant chemoendocrine therapy for breast cancer may necessitate more aggressive pharmacotherapy than is indicated for healthy postmenopausal women who develop osteoporosis. Over the last few years, clinical trials have established the effectiveness of bisphosphonates and other antiresorptive agents to preserve BMD during adjuvant therapy for early breast cancer. In addition, some bisphosphonates (eg, zoledronic acid) may also delay disease recurrence in women with hormone-responsive tumors, thereby providing an adjuvant benefit in addition to preserving BMD and potentially preventing fractures.

Conclusions

It is likely that a combined fracture risk assessment (eg, as in the WHO FRAX algorithm) will more accurately identify both women with postmenopausal osteoporosis and women with breast cancer who require bone-protective therapy.

Could targeting bone delay cancer progression? Potential mechanisms of action of bisphosphonates

Although dissemination may occur early in the course of many cancers, the development of overt metastases depends upon a variety of factors inherent to the cancer cells and the tissue(s) they colonize. The time lag between initial dissemination and established metastases could be several years, during which period the bone marrow may provide an unwitting sanctuary for disseminated tumor cells (DTCs). Survival in a dormant state within the bone marrow may help DTCs weather the effects of anticancer therapies and seed posttreatment relapses. The importance of the bone marrow for facilitating DTC survival may vary depending on the type of cancer and mechanisms of tumor cell dissemination. By altering the bone microenvironment, bisphosphonates may reduce DTC viability. Moreover, some bisphosphonates have demonstrated multiple anticancer activities. These multiple mechanisms may help explain the improvement in disease outcomes with the use of zoledronic acid in malignancies like breast cancer and multiple myeloma.

Zoledronic acid induces autophagic cell death in human prostate cancer cells

PURPOSE

Bisphosphonates are potent inhibitors of bone resorption. In vitro studies show that zolendronic acid inhibits prostate cancer cell growth by activating apoptosis. We investigated whether zolendronic acid also inhibits prostate cancer cell growth by autophagy (type II programmed cell death).

MATERIALS AND METHODS

We investigated the induction of autophagy in the PC-3, DU-145, LNCaP and CRW22Rv1 cell lines upon zolendronic acid treatment. LC3-II protein formation was detected by Western blot. LC3-II incorporation into autophagosomes was detected by immunofluorescence staining. Acidic organelle formation was detected by acridine orange staining. Rescue experiments using an apoptosis inhibitor and/or an autophagy inhibitor were performed by MTT assay.

RESULTS

Autophagy induction was detected by formation of the LC3-II protein after exposure to 100 μM zolendronic acid. LC3-II and caspase-3 processing was detected 6 days after treatment. Acidic organelles were detectable by acridine orange staining and immunofluorescence showed round-up and condensed staining of LC3-II, suggesting autophagosome formation in the cytoplasm during autophagic cell death. Cell growth was rescued only by administering an apoptosis and autophagy inhibitor during zolendronic acid treatment, indicating that zolendronic acid induces prostate cancer death by apoptotic and autophagic cell death.

CONCLUSIONS

To our knowledge we report the first study showing that zolendronic acid markedly inhibits human prostate cancer cell growth through autophagic cell death. Zolendronic acid shows its anticancer activity via apoptosis and autophagy. These findings can potentially contribute to the beneficial use of zolendronic acid for prostate cancer treatment.

The crossover of bisphosphonates to cancer therapy

Bisphosphonates form a class of drugs commonly used to treat disorders of osteoclastic bone resorption, including osteoporosis, Paget's disease of the bone, rheumatoid arthritis, and bone metastases. Although long established as the therapy of choice to treat such disorders, bisphosphonates' potential in treating cancer is garnering interest. Bisphosphonates have been demonstrated to inhibit tumor growth and metastasis, induce apoptosis in tumor cells, and encourage immune reactions against tumor cells. Current applications of bisphosphonates in cancer treatment include their use to treat skeletal metastases and as an adjuvant to endocrine therapy. This review explores bisphosphonates' current clinical utility and potential as a crossover cancer therapy.