Osteolytic bone metastases in breast carcinoma pathogenesis, morbidity and bisphosphonate treatment

Middle ear metastasis from dormant breast cancer as the initial sign of disseminated disease 20 years after quadrantectomy

We describe an unusual case of breast cancer metastatic to the middle ear in a 71-year-old woman. The metastasis was the initial sign of disseminated disease 20 years after the patient had undergone a quadrantectomy for her primary disease. Computed tomography (CT) demonstrated the presence of an intratympanic mass with a soft-tissue density that was suggestive of chronic inflammation. The patient underwent a canal-wall-down tympanoplasty. When a brownish mass was found around the ossicles, a mastoidectomy with posterior tympanotomy was carried out. However, exposure of the tumor was insufficient, and therefore the posterior wall of the ear canal had to be removed en bloc. Some tumor was left on the round window membrane so that we would not leave the patient with a total hearing loss. Our case highlights the limitations of CT and magnetic resonance imaging in differentiating inflammatory and neoplastic lesions.

Inhibition of bone resorption and growth of breast cancer in the bone microenvironment

Breast cancer frequently metastasizes to bone, where tumor cells induce osteoclasts to locally destroy bone. During bone resorption, growth factors are locally released that may support bone metastatic growth. Differently from most other tissues, drugs that can limit local turnover, such as bisphosphonates and osteoprotegerin (OPG), are available for bone. We examined the hypothesis that inhibition of bone resorption by two different mechanisms may also affect the growth of cancer cells in bone. For this, we tested the effects of high doses of OPG and zoledronic acid (ZOL) on progression of MDA-231-B/Luc+ breast cancer cells in the bone microenvironment using whole body bioluminescent reporter imaging (BLI). Both treatments significantly inhibited the development of radiographically detectable osteolytic lesions. Histologic examination corroborated the radiographic findings, showing that both treatments preserved the integrity of bone trabeculae and prevented bone destruction (significantly higher trabecular bone volumes vs. vehicle). However, whereas practically no TRAcP-positive osteoclasts were observed in tibiae preparations of animals treated with Fc-OPG, TRAcP-positive osteoclasts were still present in the animals treated with ZOL. Intra-bone tumor burden was reduced with ZOL and Fc-OPG treatment. Although there appeared to be a trend for less overall total tumor burden upon treatment with both compounds, this was not significant as assessed by BLI and histomorphometric analysis due to the extramedullary growth of cancer cells which was not affected by these treatments. Collectively, anti-resorptive agents with different mechanisms of action - ZOL and OPG - significantly reduced cancer-induced osteolysis and intra-osseous tumor burden, but failed to restrain local tumor growth. However, interference with the bone micro-environmental growth support could still be of therapeutic relevance when given to patients early in the course of bone metastatic disease.

TGF-beta and BMP7 interactions in tumour progression and bone metastasis

The skeleton is the second most frequent site of metastasis. However, only a restricted number of solid cancers, especially those of the breast and prostate, are responsible for the majority of the bone metastases. Metastatic bone disease is a major cause of morbidity, characterised by severe pain and high incidence of skeletal and haematopoietic complications (fractures, spinal cord compression and bone marrow aplasia) requiring hospitalisation. Despite the frequency of skeletal metastases, the molecular mechanisms for their propensity to colonise bone are poorly understood and treatment options are often unsatisfactory. TGF-beta and the signalling pathway it controls appears to play major roles in the pathogenesis of many carcinomas, both in their early stages, when TGF-beta acts to arrest growth of many cell types, and later in cancer progression when it contributes, paradoxically, to the phenotype of tumour invasiveness. Here we discuss some novel insights of the TGF-beta superfamily-including BMPs and their antagonists-in the formation of bone metastasis. Increasing evidence suggests that the TGF-beta superfamily is involved in bone homing, tumour dormancy, and development of micrometastases into overt bone metastases. The established role of TGF-beta/BMPs and their antagonists in epithelial plasticity during embryonic development closely resembles neoplastic processes at the primary site as well as in (bone) metastasis. For instance, the tumour-stroma interactions occurring in the tissue of cancer origin, including epithelium-to-mesenchyme transition (EMT), bear similarities with the role of bone matrix-derived TGF-beta in skeletal metastasis formation.

Inhibition of protein kinase c-Src reduces the incidence of breast cancer metastases and increases survival in mice: implications for therapy

c-Src is a proto-oncogene, belonging to the nonreceptor protein kinases family, which plays a prominent role in carcinogenesis. In this study, we tested the hypothesis that c-Src could promote breast cancer metastasis acting on several cell types and that pharmacological disruption of its kinase activity could be beneficial for the treatment of metastases. Female BALB/c-nu/nu mice were subjected to intracardiac injection of the human breast cancer cells MDA-MB-231 (MDA-231), which induced prominent bone and visceral metastases. These were pharmacologically reduced by treatment with the c-Src inhibitor [7-{4-[2-(2-methoxy-ethylamino-ethoxy]-phenyl}-5-(3-methoxy-phenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-ylamine] CGP76030 (100 mg/kg/day p.o.), resulting in decreased morbidity and lethality. Metastases were more severe in mice injected with MDA-231 cells stably transfected with wild-type c-Src (MDA-231-SrcWT), whereas transfection in injected cells of a c-Src kinase-dead dominant-negative construct (MDA-231-SrcDN) resulted in reduced morbidity, lethality, and incidence of metastases similar to the mice treated with the inhibitor. An analogous beneficial effect of c-Src inhibition was observed in subcutaneous and intratibial implanted tumors. In vitro, c-Src suppression reduced MDA-231 cell aggressiveness. It also impaired osteoclast bone resorption both directly and by reducing expression by osteoblasts of the osteoclastogenic cytokines interleukin-1beta and interleukin-6, whereas parathyroid hormone-related peptide was not implicated. c-Src was also modestly but consistently involved in the enhancement of endothelial cell proliferation in vitro and angiogenesis in vivo. In conclusion, we propose that c-Src disruption affects the metastatic process and thus is a therapeutic target for the treatment of breast cancer.

Temporal changes in bone mass and mechanical properties in a murine model of tumor osteolysis

Pathological fracture is a devastating complication of osteolytic bone metastases. The progression of osteolysis and its effect on bone fracture risk are poorly understood. The goal of this study was to determine the temporal changes in bone strength following tumor inoculation in a preclinical model of tumor osteolysis. In addition, a predictive model was developed between non-invasive radiographic measures and bone strength. The right femora of female nude mice were injected with breast cancer cells; the left limb served as a sham-operated control. Radiographs and DEXA scans were obtained at the time of surgery and at 3, 6, and 9 weeks. Groups of mice were euthanized at each time point for mechanical assessment. Micro-CT analysis was performed on a sub-set of mice with advanced state disease to quantify bone loss. Radiographs documented an increase in tumor osteolysis over time, with 58% of the mice showing signs of osteolysis at 3 weeks, 75% at 6 weeks, and 81% at 9 weeks. BMD measurements revealed a 21.6% increase from baseline in the controls whereas tumor-injected femora failed to increase in BMD over the same time course. Tumor-bearing limbs exhibited statistically significant decreases in torque at failure (86%), energy to failure (88%), and initial stiffness (94%) compared to the controls. Both lysis scores and BMD measurements proved to be modest predictors of mechanical strength, accounting for approximately 73% and 41% of variation in torque at failure, respectively. Micro-CT analysis revealed decreases in both total bone volume in the distal femur (31%) and metaphyseal fractional trabecular bone (89%). We have shown that non-invasive radiographic techniques provide a useful tool for monitoring the progression of tumor osteolysis and for predicting the mechanical strength of tumor-bearing bones in this model. By integrating non-invasive measures of tumor osteolysis and fracture risk, we have validated a clinically relevant platform for evaluating new therapeutic approaches for preserving and/or restoring bone affected by metastatic disease.

Effect of combination therapy with a novel bisphosphonate, minodronate (YM529), and docetaxel on a model of bone metastasis by human transitional cell carcinoma

PURPOSE

Transitional cell carcinoma (TCC) of the urinary tract is a chemosensitive tumor. Most deaths from TCC of the urinary tract are caused by metastasis, which is resistant to conventional chemotherapy. Frequent sites of metastases from TCC of the urinary tract are regional lymph nodes, liver, lung, and bone. Of these distant metastases, bone metastasis is consistently resistant to cisplatin-based conventional chemotherapy. Therefore, in this study, we investigated whether or not a newly developed minodronate, YM529, could prevent osteolytic bone metastasis of human TCC and also enhance the effect of docetaxel in a bone tumor model of athymic nude mice.

EXPERIMENTAL DESIGN

In the present study, we evaluated the effect of in vitro treatment with minodronate and/or docetaxel on the proliferation by cell count, the induction of apoptosis by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay, and the biological activity of osteoclast by pit formation assay in human bladder cancer cell line, UMUC-14, and mouse osteoclast cells. In vivo, we examined the effect of minodronate in a bone tumor model of athymic nude mice, in which the percutaneous intraosseal injection in the tibia of UMUC-14, leads to osteolytic bone tumor, as a bone metastasis model. To examine whether or not minodronate could inhibit tumorigenicity and enhance the effect of the chemotherapeutic agent, docetaxel, we gave minodronate i.p. and/or docetaxel i.p. to nude mice 3 days after an intraosseal tumor implantation. Moreover, proliferation and the induction of apoptosis of cancer cells and osteoclasts in bone tumors were determined by immunohistochemistry and the TUNEL assay.

RESULTS

In vitro: In vitro treatment with docetaxel inhibited proliferation and resorption pit-forming activity and induced apoptosis of mouse osteoclast cells and UMUC-14 cells. In vitro treatment with minodronate inhibited proliferation and activity and induced apoptosis of mouse osteoclast cells but not UMUC-14 cells. The treatment with minodronate enhanced the inhibition of proliferation and activity by docetaxel in osteoclasts. In vivo: In vivo combination therapy with docetaxel and minodronate significantly reduced the tumor incidence compared with the control (P < 0.05) and also growth of intraossal TCC in athymic nude mice compared with the control (P < 0.001), single therapy with docetaxel (P < 0.01), and minodronate (P < 0.05). Drug-induced body weight loss was not significantly different in any treatment group. Therapy with minodronate significantly enhanced inhibition of proliferation by docetaxel in osteoclasts of bone tumors compared with the control (P < 0.01), single therapy with docetaxel (P < 0.01), and minodronate (P < 0.05).

CONCLUSIONS

These studies indicate that combination therapy with minodronate and docetaxel may be beneficial in patients with bone metastasis of human TCC in the urinary tract.

Interference with the Microenvironmental Support Impairs the De novo Formation of Bone Metastases In vivo

Interference with the microenvironmental growth support is an attractive therapeutic strategy for repressing metastatic tumor growth. Bone is a highly dynamic tissue that is continuously remodeled by bone resorption and subsequent bone formation. Growth factors supporting bone metastatic growth are released especially during bone resorption. Differently from most other tissues, drugs that can limit local turnover, such as bisphosphonates, are available for bone. In the present study, we tested the hypothesis that inhibition of bone turnover can affect development and growth progression of experimental bone metastasis. Whole-body bioluminescent reporter imaging was used for the detection, monitoring, and quantification in vivo of the growth progression of bone metastases induced by intracardiac or intraosseous injection of luciferase-transfected breast cancer cells (MDA-231-B/luc+) to nude mice. Suppression of bone turnover by bisphosphonates, before bone colonization by cancer cells, inhibited by a great extent the number of developing bone metastasis. Tumor growth in the few, but still developing, bone metastases was affected only transiently. Reduction of bone turnover had no effect on growth progression of bone metastases, which were already established when bisphosphonate treatment was initiated, despite a substantial reduction in osteolysis. Therefore, cancer cells metastatic to bone, after an initial growth phase that depends on the interaction with the local stroma, become independent of microenvironmental growth factor support and progress autonomously. Inhibition of bone turnover may represent a useful adjuvant therapy especially for cancer patients at risk to develop bone metastasis.

Enamel matrix derivative is a potent inhibitor of breast cancer cell attachment to bone

This study examined whether enamel matrix derivative (EMD) inhibits the adhesion of cancer cells to bone. A typical breast cancer cell line, MCF-7, was used. Conditioned human osteosarcoma cell (Saos-2) medium was used as extracellular bone matrix (ECBM) to measure cell attachment. MCF-7 cells were incubated on ECBM-coated culture plates with or without soluble EMD, Arg-Gly-Asp (RGD) sequence blocking peptides, recombinant bone sialoprotein (rBSP), or specific integrin antibodies, and the attached cells were quantified using toluidine blue staining. EMD markedly reduced the attachment of MCF-7 cells to ECBM in a dose-dependent manner. An RGD peptide (GRGDSP) and recombinant BSP inhibited cell attachment to the same degree as EMD. Similarly, anti-alphavbeta3 integrin antibody strongly reduced cell attachment, whereas anti-alphavbeta5 and anti-beta1 integrin antibodies had less marked effects on cell attachment. These results show that EMD inhibits MCF-7 cell attachment to a bone matrix and that it might be useful as an anti-adhesive agent for breast cancer cells to bone in vivo.

Tumor necrosis factor-alpha induces interleukin-6 production via extracellular-regulated kinase 1 activation in breast cancer cells

Interleukin-6 (IL-6) and interleukin-11 (IL-11) are frequently produced by breast cancer cells. These interleukins promote osteoclast formation and may mediate osteolysis at the site of breast cancer bone metastases. Transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) up-regulate IL-6 and IL-11 production in a cytokine-dependent fashion in breast cancer cells, but very little is known about their intracellular signaling pathways in breast cancer cells. To study TGF-beta, TNF-alpha and IL-1beta regulation of IL-6 and IL-11 production in human MDA-MB-231 breast cancer cells, we established single cell clones stably expressing dominant negative (DN) forms of the mitogen-activated protein kinases p38 (p38/AF) or ERK1 (ERK1K71R). We show here, that while basal, TGF-beta and IL-1beta induced IL-6 production was similar in parental cells and in pcDNA3 control, ERK1K71R and p38/AF clones, TNF-alpha induced IL-6 production was blunted in the ERK1K71R clones. TGF-beta and IL-1beta, but not TNF-alpha, induced IL-11 production in parental MDA-MB-231 cells. Similar findings were detected in clones stably expressing p38/AF and ERK1K71R, which did not change basal IL-11 production either. In conclusion, TNF-alpha induced IL-6 production is mediated via ERK1 activation in MDA-MB-231 cells. These observations may be helpful in designing new anti-osteolytic therapies.

Palliative radiotherapy in the treatment of skeletal metastases

Two-third of patients with metastatic cancer suffer from pain. Pain originating from skeletal metastases is the most common form of cancer pain. Bone pain, often exacerbated by pressure or movement, limits the patient's autonomy and social life. Pathological fracture and spinal cord compression are additional complications caused by bone metastases. Radiotherapy is effective in treating bone pain not adequately controlled by analgesics. Seventy percent of patients benefit from radiotherapy. Single and multifraction regimens are equally effective in relieving pain. Retreatment is needed somewhat more often following single fraction therapy. Most patients benefit from retreatment irrespectively of previous fractionation schedule. Hemibody irradiation and radioisotopes, e.g., strontium-89 and samarium-153 are used in treating scattered painful bone metastases. Radiotherapy is used for preventing pathological fracture by treating osteolytic lesions especially in the weight-bearing bones such as the spinal column and long bones. Radiotherapy is the treatment of choice in spinal cord compression, which is the most serious complication caused by bone secondaries. Radiotherapy provides efficient, well-tolerated and cost-effective palliative care.

Differential gene expression of TGF-beta family members and osteopontin in breast tumor tissue: analysis by real-time quantitative PCR

Several cytokines including members of the transforming growth factor-beta (TGF-beta) and tumor necrosis factor (TNF) families have been implicated in the homing mechanism of breast cancer metastasis. We hypothesize that primary breast tumor tissues differentially express modulators of bone cell function and that this expression pattern contributes to their aggressive and metastatic potential and to their capacity to establish and grow in bone. We, therefore, examined the gene expression pattern of the TGF-beta family members (inhibin/activin betaA subunit (activin betaA), inhibin alpha subunit, and bone morphogenetic protein-2 (BMP-2)), the TNF family members (receptor activator of NF-KB ligand (RANKL) and osteoprotegerin (OPG)), and osteopontin (OPN) in normal, non-invasive, invasive, and metastatic human breast cancer specimens. The mRNA transcript levels of these genes were quantified by reverse transcription (RT) and fluorescent-based kinetic PCR in 18 normal breast tissues, five ductal carcinoma in situ (DCIS). 24 primary breast tumor tissue, and five distant metastases. The mRNA transcript level of each gene was normalized to the amount of beta-actin present in the samples. We observed differential gene expression of the selected TGF-beta family members as well as OPN in breast cancer progression. The average gene expression of the putative tumor suppressor, inhibin alpha, did not significantly change in any of the tumor tissues examined compared to normal breast tissue. The mRNA level of BMP-2, a protein with anti-proliferative effects in breast cancer cell lines and involved in bone formation, significantly decreased in non-invasive, invasive, and liver metastatic breast tumor tissue compared to normal breast tissue. The gene expression of activin betaA, a protein involved in cell proliferation and osteoclast induction, increased in invasive and bone metastatic tumor tissue compared to normal breast tissue. The mRNA level of OPN, a bone matrix protein associated with enhanced malignancy, increased in non-invasive, invasive, and liver and bone metastatic breast tumor tissue compared to normal breast tissue. In contrast, the average gene expressions of the TNF family members, RANKL and OPG, proteins involved in the regulation of osteoclastogenesis, were only slightly if at all changed in the different stage breast tumor tissues. These results suggest that differential gene expression of bone-related proteins, especially OPN, activin betaA, and BMP-2, by primary breast tumor tissues may play a significant role in the invasiveness and metastatic potential of breast cancer.

Direct effects of bisphosphonates on breast cancer cells

In addition to inhibiting bone resorption, bisphosphonates have also been shown to exhibit antitumour effects. In vitro, bisphosphonates inhibit proliferation and induce apoptosis in cultured human breast cancer cells. In addition, bisphosphonate treatment interferes with breast cancer cell adhesion to bone matrix, and inhibits cell migration and invasion. The combination of bisphosphonates with other anticancer drugs such as the taxoids markedly enhances these effects. These newly recognized direct actions of bisphosphonates on breast cancer cells indicate that these agents may have a greater role to play in treatment of patients suffering from cancers with a propensity to metastasize to bone.

Principles of perioperative pain management in older adults

The consequences of poor planning for pain management during surgery of geriatric patients not only affect the immediate well-being of the patient but also have terrible socioeconomic implications. Delays in rehabilitation, increases in hospital lengths of stay, and increased comorbidity can be expected if interventions for pain management are either inadequate or excessive without appropriate monitoring. During surgery, seniors are likely to suffer from acute and chronic pain that must be addressed aggressively in the postoperative period to ensure a rapid functional recovery. New pain scales have been developed with seniors in mind, and greater testing of older scales in elderly populations have helped to identify measures of pain more suited to frail seniors. This article is designed to help clinicians to strategically implement optimal pain management principles and techniques and, thus, help to fulfill the obligation to relieve pain and suffering in patients in the perioperative period, which will ensure the greatest chance of recovery to optimal independence for patients.

Monitoring metastatic behavior of human tumor cells in mice with species-specific polymerase chain reaction: elevated expression of angiogenesis and bone resorption stimulators by breast cancer in bone metastases

Tumor-stroma interactions are of primary importance in determining the pathogenesis of metastasis. Here, we describe the application of sensitive competitive polymerase chain reaction (PCR) techniques for detection and quantitation of human breast cancer cells (MDA-MB-231) in an in vivo mouse model of experimental metastasis. Human-specific oligonucleotide primers in competitive PCR reactions were used to quantify the amount of MDA-MB-231 cells per tissue per organ. Using this species-specific (semi)quantitative PCR approach, gene expression patterns of (human) tumor cells or (mouse) stromal cells in metastatic lesions in the skeleton or soft tissues were investigated and compared. In all metastatic lesions, MDA-MB-231 cells express angiogenic factors (vascular endothelial growth factors [VEGFs]; VEGF-A, -B, and -C) and bone-acting cytokines (parathyroid hormone-related protein [PTHrP] and macrophage colony-stimulating factor [M-CSF]). In these metastases, PECAM-1-positive blood vessels and stromal cells of mouse origin are detected. The latter express angiogenic factors and markers of sprouting vessels (VEGF receptors flt-1/flk - 1/flk-4 and CD31/PECAM-1). Strikingly, steady-state messenger RNA (mRNA) levels of VEGF-A and -B and the major bone resorption stimulators PTHrP and M-CSF by tumor cells were elevated significantly in bone versus soft tissues (p < or = 0.05, p < or = 0.0001, p < or = 0.001, and p < or = 0.05, respectively), indicating tissue-specific expression of these tumor progression factors. In conclusion, MDA-MB-231 breast cancer cells express a variety of factors in vivo that have been implicated in metastatic bone disease and that correlate with poor survival of patients with breast cancer. We hypothesize that the observed up-regulated expression of angiogenic and bone-resorbing factors by the breast cancer cells in the skeleton underlie the clinically observed osteotropism of breast cancer cells and pathogenesis of osteolytic bone metastases. The application of the species-specific competitive PCR-based assay in vivo can provide new information concerning the involvement of gene families in tumor progression and metastatic disease and greatly facilitates the study of tumor-stroma interactions in cancer invasion and metastasis.

Pain management in older adults: prevention and treatment

The release of guidelines in 1998 by the American Geriatrics Society on "The Management of Chronic Pain in Older Persons" was a breakthrough in helping to manage pain in this population. Already advances have fostered a need to update recommendations. This article focuses on the treatment strategies available for seniors that are likely to help to fulfill the obligation to relieve pain and suffering in patients. A review was done of the literature using Medline and other search techniques. New pain scales have been developed with seniors in mind and greater testing of older scales in elderly populations have helped to identify measures of pain more suited to frail seniors. Advances in cyclooxygenase inhibition selectivity, alternative medicine, and progress in the identification of nonopioid pain receptors and the development of products to target them are just a few of changes that have altered the way clinicians think about treating pain. The use of hospice in end-of-life palliative care is a valuable resource for clinicians managing pain at that phase in care as well. Tools are available to prevent and treat pain successfully in seniors. Educating clinicians about available assessment tools, techniques and interventions may be the biggest challenge to comforting the older adult in pain.

Bone morphogenetic proteins secreted by breast cancer cells upregulate bone sialoprotein expression in preosteoblast cells

It is well established that bone metastases comprise bone; however, the exact factors/mechanisms involved remain unknown. We hypothesized that tumor cells secreted factors capable of altering normal bone metabolism. The aims of the present study were to (1) determine the effects of secretory products isolated from HT-39 cells, a human breast cancer cell line, on osteoprogenitor cell (MC3T3-E1 cells) behavior, and (2) identify tumor-derived factor(s) that alters osteoblast activities. Conditioned media (CM) from HT-39 cells were collected following a 24-h serum-free culture. The ability of CM to alter gene expression in MC3T3-E1 cells was determined by Northern analysis. CM effects on cell proliferation and mineralization ability were determined using a Coulter counter and von Kossa stain, respectively. MC3T3-E1 cells were treated with CM plus noggin, a factor known to block bone morphogenic proteins (BMPs), to determine whether BMPs, shown to be present in CM, were linked with CM effects on MC3T3-E1 cell activity. In addition, inhibitors of MAP kinase kinase (MEK), protein kinase C (PKC), and protein kinase A were used to identify the intracellular signaling pathway(s) by which the active factors in CM regulated osteoblast behavior. CM treatment significantly enhanced BSP mRNA (2.5-fold over control), but had no effect on cell proliferation. Mineralization assay showed that CM enhanced mineral nodule formation compared to controls. Noggin inhibited CM-induced upregulation of BSP mRNA, suggesting that BMPs were responsible for upregulating BSP gene expression in MC3T3-E1 cells. The PKC inhibitor blocked CM-mediated upregulation of BSP, suggesting involvement of the PKC pathway in regulating BSP expression. BMPs secreted by HT-39 cells may be responsible for enhancing BSP expression in MC3T3-E1 cells. Continued studies targeted at determining the role of BMPs in regulating bone metabolism are important for understanding the pathogenesis of bone diseases.

Tumour progression and angiogenesis in bone metastasis from breast cancer: new approaches to an old problem

Breast cancer metastasizes frequently to the skeleton and causes considerable morbidity and deterioration of the quality of life. The clinical consequences of skeletal metastases are bone pain, pathological fractures, hypercalcaemia and nerve compression syndromes. From the moment breast cancer cells are located in the bone microenvironment, they may release factors which stimulate bone resorption and angiogenesis leading to growth of skeletal metastases and a subsequent selective increase in the attraction of new cancer cells to bone. In this review, emerging new concepts of breast cancer-bone interactions, in particular the involvement of angiogenesis, proteolysis and the role of cancer-induced bone resorption in skeletal metastasis are discussed. Better understanding of the processes involved in the metastasis of cancer cells to bone, local tumour growth and subsequent destruction of skeletal architecture can lead to optimal methods for the prevention and treatment of metastatic bone disease.

Clodronate: a review of its use in breast cancer

Like other members of its class, the bisphosphonate clodronate (clodronic acid) inhibits bone resorption. The efficacy of oral clodronate 1600 mg/day in reducing the incidence of skeletal complications and metastasis development has been assessed in several clinical trials in patients with breast cancer. Long term use of oral clodronate significantly reduced the total cumulative incidence of skeletal events (including fractures, hypercalcaemia, and the need for radiotherapy for bone pain) compared with that in placebo recipients in 2 randomised double-blind placebo-controlled studies, each involving >100 patients. Significant differences in favour of clodronate were also seen in the frequency of some individual skeletal events in 1 trial. A nonblind trial in 302 patients considered to be at high risk of developing metastases found that, at a 3-year follow-up, significantly fewer patients who received clodronate for 2 years developed skeletal metastases than those in a control group. Clodronate recipients were also significantly less likely than controls to develop visceral metastases, and had significantly higher survival rates. A smaller double-blind placebo-controlled study in women with recurrent breast cancer found that clodronate significantly decreased the total number of new skeletal metastases, but not the number of patients who developed them. In a nonblind trial in 299 patients with node-positive breast cancer, however, the incidence of skeletal metastases did not differ significantly between patients who received clodronate for 3 years and those in a control group. In addition, clodronate recipients had a significantly greater incidence of nonskeletal metastases (local and visceral), and significantly lower survival rates. Intravenous or oral clodronate has been well tolerated in clinical trials. The most common adverse effects reported were mild gastrointestinal disturbances such as nausea, vomiting and diarrhoea. All these events were transient, and usually resolved without stopping treatment.

CONCLUSIONS

Clodronate is a well tolerated bisphosphonate, available in both oral and intravenous forms, that significantly reduces the incidence of skeletal complications associated with breast cancer. Further research is needed to establish more clearly its efficacy in reducing metastasis development, to assess its efficacy compared with other bisphosphonates, and to determine which patients will benefit most from treatment. Currently, clodronate is probably most effective in the treatment and prevention of general skeletal complications in patients with breast cancer.

Bisphosphonates in the treatment of malignant bone disease

Tumor-induced osteolysis or lytic bone disease is mediated by osteoclast activation. Osteoclasts can be activated directly by products produced by tumors or indirectly through other nonmalignant cells. By reducing osteoclastic activity, bisphosphonates inhibit bone resorption. Since these agents were shown effective in treating other diseases associated with increased bone resorption, including cancer-related hypercalcemia and Paget's disease of bone, studies have been initiated to explore the use of bisphosphonates in patients with osteolytic bone metastases. Recent large randomized double-blind studies show the efficacy of these agents in reducing skeletal complications in patients with bone metastases from both breast cancer and multiple myeloma.

Alendronate blocks metalloproteinase secretion and bone collagen I release by PC-3 ML cells in SCID mice

We have previously shown that alendronate, a potent bisphosphonate compound, can prevent human PC-3 ML tumor cell metastasis to the bone (Stearns and Stearns, 1996, Oncol Res, 8, 69-75). In this paper, tumor cells were injected into the bone medullary cavity of SCID mice femurs both in vivo and following isolation in vitro. ELISAs showed that the amount of collagen I released in the bone marrow (i.e. in in vitro experiments) and the blood plasma (i.e. in in vivo experiments) was a function of the time of incubation or the number of cells injected in the femurs. ELISAs also showed that the levels of matrix metalloproteinase (MMP-2 and MMP-9) secreted in the bone medullary cavity of the femurs directly correlated with the extent of collagen 1 release. In vitro experiments carried out with 'live' and 'devitalized bone' yielded similar results suggesting that the tumor cells (not the osteoclasts) were primarily responsible for the bone solubilization observed. Alendronate pretreatment of the SCID mice (0.1 mg/kg biweekly for 3 weeks) (or the tumor cells) blocked both MMP production by the tumor cells (and the osteoclasts) and collagen I release, providing direct evidence that alendronate might be utilized to prevent bone destruction by metastatic tumor cells. Zymography indicated that MMP-2 activation might be responsible for bone solubilization. In addition, the data suggest that the plasma levels of collagen I might be a marker of bone metastasis and osteolysis.

Alendronate blocks TGF-beta1 stimulated collagen 1 degradation by human prostate PC-3 ML cells

We have previously shown that alendronate can prevent human PC-3 ML tumor cell metastasis to the bone (Wang and Stearns, 1991, Differentiation, 48, 115-25). In this paper, ELISAs and Western blots showed that TGF-beta1 stimulated the secretion of a 72 kDa matrix metalloproteinase 2 (MMP-2) to enhance the solubilization of radiolabeled collagen 1 by metastatic human prostate PC-3 ML cells. A potent bisphosphonate compound, alendronate, inhibited MMP-2 secretion to block solubilization of collagen 1. Alendronate failed to inhibit MMP-2 activity directly, but instead appeared to block cellular secretion of MMP-2. Alendronate failed to inhibit secretion of tissue inhibitor of metalloproteinase-2 (TIMP-2; the inhibitor of MMP-2) and the decrease in collagen 1 solubilization observed may occur, in part, from changes in the molar stoichiometry of TIMP-2 to MMP-2. We conclude that alendronate may be a potent inhibitor of bone resorption based on its ability to block MMP-2 secretion by tumor cells.

Bisphosphonates inhibit the adhesion of breast cancer cells to bone matrices in vitro

Bisphosphonates are used with increasing frequency in the management of skeletal complications in patients with breast cancer. In this paper, we have investigated whether bisphosphonates, besides their known beneficial effects on tumor-associated osteoclastic resorption, are capable of inhibiting breast cancer cell adhesion to bone matrix. For that we used two in vitro models for bone matrix (cortical bone slices and cryostat sections of trabecular bone from neonatal mouse tails). Four bone matrix-bound nitrogen-containing bisphosphonates (pamidronate, olpadronate, alendronate, and ibandronate) inhibited adhesion and spreading of breast cancer cells to bone dose-dependently, whereas etidronate and clodronate had little or no effect. Strikingly, the relative order of potency of the bisphosphonates in inhibiting the adhesion of cancer cells to cortical and trabecular bone corresponded to their relative antiresorptive potencies in vivo as well as their ranking in in vitro bone resorption assays with predictive value for their clinical efficacy. It appears that nitrogen-containing bisphosphonates alter selectively the adhesive properties of the extracellular bone matrix preventing the attachment of breast cancer cells to it. Besides the beneficial effects of bisphosphonates on tumor-induced osteoclastic resorption, the previously unrecognized effect presented in this paper makes these agents suitable for earlier pharmacologic intervention in patients with breast cancer at risk of developing bone metastases.

Effects of oral clodronate on bone mineral density in patients with relapsing breast cancer

The high prevalence of bone metastases in breast cancer and the risk that spinal and femoral osteoporosis may add further morbidity provide a rationale for bisphosphonate therapy in patients with skeletal metastases from mammary carcinoma. We investigated the effects of oral clodronate given during 9 months, with a 24-month follow-up, on bone mineral density (BMD), on biochemical markers of bone remodeling, and on osseous complications in 67 women with documented relapsing breast cancer, aged 58.7 +/- 1.5 years (x +/- SEM). Patients with active cancer disease were randomly allocated to two groups, with or without clodronate treatment (1600 mg/day, orally). Twenty-six women considered in complete remission (52.4 +/- 2.4 years) were also studied. Expressed in deviation from gender- and age-matched normals (z score), base-line BMD at the levels of lumbar spine (LS), femoral neck (FN), and midfemoral shaft (FS) was +0.10 +/- 0.22 vs. -0.12 +/- 0.25, +0.03 +/- 0.19 vs. -0.54 +/- 0.24, and +0.08 +/- 0.14 vs. -0.02 +/- 0.22, in patients with active breast cancer and in subjects in remission, respectively. After 9 months of treatment, fasting urinary calcium to creatinine ratio was lower (0.26 +/- 0.04 vs. 0.40 +/- 0.04 mmol/mmol creatinine, p < 0.02) and serum osteocalcin was stabilized (-2.1 +/- 1.1 vs. +7.0 +/- 3.3 micrograms/L, as compared with pretreatment values, p < 0.02), in the clodronate-treated group. The rate of osseous complications (pathological fracture, hypercalcemic episode, scintigraphic or radiological evidence of metastasis development, chemo- or radiotherapy for bone disease progression) was 28.8 events per 100 patient-year in the clodronate-treated group vs. 39.0 in controls, and 31.5 vs. 40.5, after 9 and 15 months of follow-up, respectively. In 15 women without evident LS bone metastasis (7 clodronate-treated and 8 controls), LS BMD increased in the clodronate-treated group by +5.2 +/- 2.5% vs. -0.3 +/- 1.4%, and +8.1 +/- 4.7 vs. -0.9 +/- 1.7, after 10.3 +/- 0.4 and 17.3 +/- 1.2 months, respectively (p < 0.01), as compared with pretreatment values. These results indicate that clodronate treatment decreased bone turnover and attenuated cancer-related bone morbidity. In addition, clodronate increased LS BMD in apparently unaffected bone of women with relapsing breast cancer.

Does supportive pamidronate treatment prevent or delay the first manifestation of bone metastases in breast cancer patients?

The effect of pamidronate treatment on the first development of bone metastases was investigated in 124 patients with breast cancer, with either locally advanced disease (n = 33) or extraskeletal metastases (n = 91), but no bone metastases in a randomised, multicentre, open controlled study. Patients were assigned to treatment with oral pamidronate, 300 mg/day, (n = 65) or to a control group (n = 59). Tumour therapy was freely allowed. A first clinical event of skeletal morbidity occurred in 22% pamidronate and 20% control patients; unequivocal first radiological manifestation of bone metastases was found in 36% pamidronate and 27% control patients (n.s.). The actuarial risk of a first skeletal event was similar in both groups. Quality-of-life measurements of bone metastases-related aspects showed no differences between the two groups. 19 patients withdrew from the study because of gastrointestinal complaints attributed to pamidronate. We conclude that supportive oral pamidronate treatment (300 mg/day) does not prevent nor delay the development of bone metastases in breast cancer patients at risk.

Clodronate and other bisphosphonates as supportive therapy in osteolysis due to malignancy

Clodronate, one of the most investigated bisphosphonates, has been clinically utilised for over 10 years in malignancy. It is the most used, most effective and safest drug in the treatment of hypercalcaemia. It inhibits lytic bone destruction, prevents bone fractures and relieves bone pain. Supportive clodronate therapy may even reduce hypercalcaemia mortality and the morbidity caused by osteolysis. These results have stimulated studies on the patients' quality of life. New methods for the measurement of bone resorption, such as the degradation product of type I collagen (ICTP), may improve the possibility of monitoring the effect of clodronate. Comparative studies with different bisphosphonates in hypercalcaemia and long-term controlled trials using bisphosphonates as supportive therapy in osteolysis due to malignancy are reviewed.

Effect of the bisphosphonate risedronate on bone metastases in a rat mammary adenocarcinoma model system

Risedronate (NE-58095) is a third-generation bisphosphonate with very potent antiresorptive activity but few toxic effects. The purpose of this work was to evaluate the effect of risedronate treatment on bone metastases produced in a rat breast cancer model. Berlin Druckrey IV rats inoculated with ENU1564 mammary adenocarcinoma cells were treated daily with risedronate or a saline placebo. Survival times, dictated by extraskeletal metastases (lung, heart, and brain), were not affected by risedronate treatment. Risedronate-treated animals had skeletal changes associated with decreased remodeling of bones undergoing endochondral ossification, most prominently affecting the appendicular skeleton. Despite the skeletal alterations induced by the treatment, the distribution of bone metastases throughout the surveyed skeletal sites was similar for treated and untreated animals. Bone metastases were enumerated in histologic sections of distal femur, spine, and skull. Tumor size was estimated from area measurements obtained from histologic lesions in distal femoral metaphyses and vertebral bodies. A greater number of treated rats had no bone metastases in any of the examined sections (30 versus 16.1% of untreated rats). Multiple bone metastases were observed less frequently in treated rats (33.3 versus 71% of untreated rats). Treated rats had fewer observed bone metastases in each examined site than untreated rats (p < or = 0.025). Mean tumor areas in femora and vertebrae were smaller in treated rats (p < or = 0.05), due to the less frequent presence of very large lesions. In untreated animals, osteoclasts appeared to be active at the tumor/bone interface and osseous structures were often completely replaced by expanding tumors. In contrast, metastases in treated animals caused less disruption of skeletal histoarchitecture. The apparent lack of osteoclastic activity and retention of bone within lesions suggested a decreased contribution of osteoclasts to the bone resorptive process. An in vivo immunohistochemical cell proliferation assay failed to reveal differences in the percentage of dividing tumor cells in bone metastatic sites in treated versus untreated animals. The results demonstrate significant effects of risedronate treatment on the incidence and size of observed skeletal metastases in this model.

Double blind radiological assessment of continuous oral pamidronic acid in patients with rheumatoid arthritis

Continuous oral pamidronate (APD), 1000 mg/day, was administered to 14 patients with rheumatoid arthritis. A control group of 13 patients with similar conditions received placebo under a double blind randomized study design. Periarticular erosion scores were significantly higher in the control group after 12 months treatment. This was attributed to a deterioration in this group rather than to an improvement in the APD treated one. By contrast, intraarticular narrowing score was not influenced by APD. Tolerance to oral APD was acceptable in all patients.

Disodium Pamidronate in the Treatment of Bone Metastases from Breast Cancer

Aims and Background

Symptomatic relief of bone metastases with biphosphonates has been previously reported, but limited data are available on the possibility of the induction of sclerosis in osteolytic lesions.

Methods

We therefore initiated an open study with disodium pamidronate (45 mg infused over 1 h and repeated every 21 days) in patients with bone metastases from breast cancer pretreated with chemotherapy and/or hormonetherapy. Fourteen patients wiht measurable lytic or mixed bone disease entereted the study. No other systemic therapy for breast cancer was allowed after their Inclusion in the study.

Results

No radiologic evidence of bone sclerosis of lytic disease was seen. After 2 months of therapy, 9 patients had progressed and 5 had stable disease. The median time to progression of bone disease was 1.6 months (range, 1-9). No significant improvement in terms of symptomatic status or analgesic consumption was recorded. The treatment was well tolerated, and no significant local or systemic toxicity was observed.

Conclusions

Disodium pamidronate at a dose of 45 mg every 3 weeks is not capable of inducing sclerosis of lytic lesions from pretreated breast cancer. Further trials concentrating on higher dosages of disodium pamidronate are warranted.

Hypercalcemia and breast cancer related to parathormone-like secretion by liver metastases

A premenopausal woman developed hypercalcemia 30 months after treatment for infiltrating breast cancer. After bone metastases had been excluded, primary hyperparathyroidism was suspected. A parathyroid adenoma was removed and histologically confirmed. Hypercalcemia, associated with low plasma phosphate and severely depressed plasma parathormone (PTH) levels, persisted. Further investigations showed liver metastases from the primary breast cancer and also secretion of a PTH-like substance. Antitumoral treatment was effective on the liver metastases and also normalized calcemia and the PTH-like substance, demonstrating the existence of a paraneoplastic syndrome related to the secretion of a PTH-like substance by disseminated liver metastases of primary breast cancer.

A quantitative model for spontaneous bone metastasis: evidence for a mitogenic effect of bone on Walker 256 cancer cells

A new model for the study of spontaneous bone metastasis has been developed which allows for the quantification of metastatic tumor burden and cancer cell growth rate, and which describes the progressive changes in bone morphology. Walker 256 (W256) cells or vehicle were injected into the left upper thigh muscle of male Fischer rats, which were killed 7, 10 or 14 days later. By day 7, metastases had appeared in the distal femur, in the glomeruli of the kidney, and diffusely throughout the liver and lungs. The extent of tumor burden in these organs increased over time. In the femur, 14 days of tumor burden was associated with a 53 +/- 10% decrease in trabecular bone content, a 61 +/- 15% increase in osteoclast surface, and a 95 +/- 10% decrease in osteoblast surface, as compared with non-tumor-bearing controls. By autoradiography, metastatic tumor cells in all organs were determined to have greater growth rates than did cells in the primary tumor. However, within the femur, W256 cells located adjacent to trabecular bone surfaces had a 33 +/- 7% greater growth rate than did W256 cells located > 50 microns from bone surfaces (P < 0.05), suggesting a mitogenic effect of bone.

Pamidronate

OBJECTIVE

The primary objective of this article is to introduce readers to the use of a new agent, pamidronate. The article discusses its use in hypercalcemia of malignancy (HCM), osteolytic lesions, and Paget's disease. Pharmacokinetic data and clinical trials are reviewed, as well as adverse effects and dosage guidelines.

DATA SOURCES

A MEDLINE search was used to identify English-language studies involving pamidronate for the period from 1970 to 1992.

STUDY SELECTION

As comparative trials were few in number, trials using pamidronate as a single agent were also reviewed.

DATA EXTRACTION

Sparse pharmacokinetic data were obtained from clinical trials. All clinical trials available at the time of publication that met the following criteria were reviewed: (1) allowed for adequate rehydration prior to drug therapy; (2) reported standardized and corrected serum calcium concentrations; (3) separated data obtained from patients who received pamidronate alone from those who received pamidronate and concurrent chemotherapy.

RESULTS

Pamidronate has a pharmacologic profile similar to that of etidronate, but pamidronate is more potent and has a longer duration of effect. It has been investigated primarily in the treatment of HCM as well as in the treatment of osteolytic bone metastases and Paget's disease. In hypercalcemia of malignancy it appears to be as effective as established agents with the advantage that a single dose of pamidronate 90 mg iv provides a durable response. In Paget's disease chronic oral administration has also been shown to be effective in relieving bone pain. Adverse reactions with intravenous administration are transient and self-limiting and usually occur with the first dose. The most common adverse effect is a transient and self-limiting fever. Chronic oral administration of doses greater than 600 mg/d is associated with gastrointestinal toxicities.

CONCLUSIONS

Although more well-designed clinical trials comparing pamidronate with standard therapies and other available agents are necessary, initial results indicate that pamidronate is an effective and promising alternative for use in the treatment of HCM.

[Osteolytic metastases of breast cancer and biphosphonates]

Three-quarters of breast carcinomas at an advanced stage display metastases, usually of the osteolytic type. Osteolysis results from a predominant increase of osteoclastic activity stimulated by humoral or local factors secreted by cancerous cells. Bisphosphonates interfere with osteoclasts and therefore can reduce the osteolysis. These compounds act through three main mechanisms: physico-chemical inhibition of bone crystal, cytostatic effect on osteoclasts, and in the case of pamidronate, direct or indirect action on the mononucleate precursors of osteoclasts. Three bisphosphonates are now available: etidronate, clodronate and pamidronate. Ten published studies report on their use in breast carcinoma with osteolytic metastases, and without hypercalceamia. Four studies concern clodronate in 54 patients, and six studies concern pamidronate in 128 patients. Intravenous pamidronate seems to be the more effective of the two, with densification of the lytic areas in 25% of the cases. All studies mention a decrease of pain, risk of fracture, hypercalcaemia and new metastatic locations. Side-effects are minimal. Controlled studies are needed to confirm the position of bisphosphonates in the management of malignant osteolysis.

Intravenous clodronate for the treatment of hypercalcaemia in breast cancer patients with bone metastases--a prospective randomised placebo-controlled multicentre study

In a double blind randomised multicentre study the effect of intravenous clodronate plus hydration was compared with placebo plus hydration in the treatment of hypercalcaemia in breast cancer patients with bone metastases. The patients were treated either with hydration plus clodronate 300 mg/day or hydration plus placebo, up to 7 days or until serum ionised calcium was below 1.4 mmol/l. 25 patients received clodronate and 19 placebo. A significant difference in favour of clodronate was observed in the time to reach normocalcaemia (P = 0.004) and in the number of patients achieving normocalcaemia (P = 0.0003). 17 patients of 21 evaluable patients on clodronate achieved normocalcaemia compared with 4 of 19 patients on placebo. The only adverse event clearly associated with clodronate was symptomatic hypocalcaemia in 1 patient. Thus, clodronate seems to be a safe and highly efficacious drug for the treatment of hypercalcaemia in breast cancer patients.

Influence of dichloromethylene bisphosphonate on the in vitro phagocytosis of hydroxyapatite particles by rat peritoneal exudate cells: an electron microscopic and chemiluminescence study

Transmission electron microscopy and standard chemiluminescence assays were used to investigate the in vivo effect of dichloromethylene bisphosphonate (clodronate) on the phagocytosis of pure hydroxyapatite particles by rat peritoneal macrophages and the production of chemiluminescence by the peritoneal exudate cells. Hydroxyapatite (control) and a hydroxyapatite/clodronate suspension (28 mumol clodronate per gram of hydroxyapatite, experimental) were injected into the peritoneum of rats, the clodronate dose being 10 micrograms/kg. Macrophages were harvested at 12, 24, 48, and 96 hours after injection and the particle phagocytosis was assessed by transmission electron microscopy. Hydroxyapatite alone was completely phagocytosed by 24 hours and hydroxyapatite reacted with clodronate was completely phagocytosed by 48 hours. From 48 hours onwards hydroxyapatite particle dissolution was observed in the phagosomes of cells in the two groups. At 48 hours the chemiluminescence produced by the peritoneal exudate cells was also measured. Clodronate and clodronate/hydroxyapatite enhanced cell activity on subsequent challenge with phorbol myristate acetate or zymosan. Clodronate seemed to exhibit an inhibitory effect on the phagocytic activity and an enhancement of the chemiluminescence production by the cells in this model, indicating that it was modifying the inflammatory cell response.

The effect of supportive pamidronate treatment on aspects of quality of life of patients with advanced breast cancer

Selective aspects of quality of life during supportive pamidronate (APD) treatment were assessed in breast cancer patients with osteolytic metastases. 144 patients were randomised to a pamidronate group (n = 76) or a control group (n = 68). A questionnaire measuring mobility impairment, bone pain, fatigue and gastrointestinal toxicity was administered at 3-monthly intervals. The analysis focused on changes in these quality of life domains over time. The median follow-up for both groups was 18 months. Mobility impairment and bone pain were significantly less in the pamidronate group as compared with the control group, due primarily to a rapid improvement shortly after initiation of pamidronate treatment. Thereafter, a gradual increase in these symptoms was noted in both groups. Gastrointestinal complaints and fatigue levels were similar over time in the two groups, suggesting that these symptoms are more dependent on disease-related events and cytotoxic treatment than on pamidronate treatment. The results indicate that reduced skeletal morbidity in breast cancer patients during pamidronate treatments is associated with an improvement in selective aspects of quality of life.

Treatment of tumor-induced osteolysis by APD

Bisphosphonates, associated with rehydration, became the treatment of choice of malignant hypercalcemia when it became apparent that these compounds normalized plasma calcium in most cases within a few days and with almost no side effects, and that their effect was prolonged. Dichloromethylene bisphosphonate and aminobisphosphonate, especially APD, were shown to inhibit bone resorption with no noticeable inhibition of bone formation, and were highly effective in the long-term treatment of Paget's disease. APD was used in almost 300 patients with malignant hypercalcemia published in the literature and has been used in the medical clinic at Lausanne for several years. When given to 14 patients with malignant hypercalcemia at the dose of 25 mg/day until plasma calcium became normal for two consecutive days, APD had to be given for 4-11 days, severe hypercalcemia needing longer treatment than mild hypercalcemia (Adami et al. 1982). When given for a fixed period of 6 days, again plasma calcium normalized in all patients, whether APD was given i.v. (30 mg/day, ten patients) or orally (1200 mg/day, ten patients) (Adami et al. 1985). Further shortening of the treatment to one single infusion given over 24 h did not decrease the efficacy, as long as high enough doses were given (Blomqvist 1986). For severe hypercalcemia of above 3.5 mmol/liter 60-90 mg had to be given, while 30-45 mg was sufficient in milder cases (Body 1984). Otherwise, mild, transient, and asymptomatic hypocalcemia could occur. Normalization of plasma calcium went along with clinical improvement, sometimes even with correction of coma. Renal function was improved, even when the initial plasma creatinine levels were up to twice normal. Hypercalcemia could reoccur, but the duration of the effect of APD (1 week to several months) depended among other things on the dose administered. The decrease in plasma calcium was accompanied by a decrease in urinary calcium and hydroxyproline, both showing inhibition of bone resorption. In the case of recurrency, the treatment could be repeated with almost unaltered efficacy, except in end-stage cancer disease. When given to 13 normocalcemic patients with bone metastases from breast cancer, hydroxyproline and urinary calcium again decreased. Bone pains and radiologic signs of metastatic bone resorption also showed significant improvement, although these latter effects could also be explained by the antitumoral treatment, in this uncontrolled open trial.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of long-term bisphosphonate treatment on morbidity due to bone metastases in breast cancer patients

The effect of long-term bisphosphonate (APD) treatment on the morbidity from bone metastases in breast cancer patients was studied in a controlled clinical trial. 131 patients were randomized between treatment with APD (300 mg/day orally) or control. Systemic treatment for breast cancer was left to the discretion of the physician. The distribution of cases according to age, receptor status and previous treatment was similar in both groups. Patients were examined at 3-month intervals, while bone scans and radiography of relevant lesions in the skeleton were performed every 6 months. After a median follow-up of 13 months, the morbidity in the treated group was significantly less than in the controls. This concerned the occurrence of hypercalcemia, bone pain and fractures, and the need for radiotherapy of osteolytic lesions. In this interim analysis, APD treatment more than halved the requirement for specific treatment of bone lesions. The treatment is simple and well tolerated at a relatively low dosage. A higher oral dose was precluded due to gastrointestinal toxicity. Because the effect of APD on skeletal morbidity was not complete, efforts should be made to develop more effective and less toxic bisphosphonates.

Reduced morbidity from skeletal metastases in breast cancer patients during long-term bisphosphonate (APD) treatment

131 patients with osteolytic metastases from breast cancer were randomised to receive long-term oral treatment with aminohydroxy-propylidene-bisphosphonate (APD), 300 mg daily (n = 70), or to act as controls (n = 61) in a multicentre trial. Specific antitumour therapy was at the discretion of the clinician and variable. An interim analysis was made after a median follow-up of 13 months in the APD group and 14 months in the controls. There was a significant reduction in pathological fractures and severe bone pain in the APD group, and hypercalcaemia was prevented. Consequently the necessity for radiotherapy for skeletal complications was more than halved; the number of systemic therapy changes was also reduced. Gastrointestinal side-effects of APD led to a drop-out of 8% of patients. Oral supportive APD therapy is simple and convenient, and significantly reduced skeletal morbidity in advanced breast cancer.

3(Amino-1,1-hydroxypropylidene) bisphosphonate (APD) for hypercalcaemia of breast cancer

The effect of a single dose of APD on hypercalcaemia has been studied in advanced breast cancer. Twenty-five patients were rehydrated intravenously for 48 h. Twenty-three remained hypercalcaemic and received 5-15 mg APD as a 2 h infusion. Eighteen patients achieved normocalcaemia, 15 after a dose of less than or equal to 15 mg. One patient died within 24 h from rapidly advancing disease and 4 remained hypercalcaemic. Urinary calcium excretion increased during rehydration as glomerular function improved and tubular reabsorption of calcium fell. After APD, calcium excretion fell to normal in 22/24 patients reflecting inhibition of bone resorption. Hydroxyproline excretion remained high. The effect of a single dose of APD on hypercalcaemia lasted a median of 11 days (range 7-17). Transient fever occurred in 2 patients, but there were no other side effects. The possibility of long-term control of osteolysis using a 2 weekly schedule of APD administration is now being studied.