The hypercalcemia of malignancy: pathogenesis and management

Hypercalcemia affected in metastatic breast cancer patients without bone metastasis: report of three cases

Background

Since humoral hypercalcemia of malignancy (HHM) in breast cancer patients without bone metastasis is rare, the clinical features of this condition are not fully understood.

Case presentation

During the recent 12 years, 3602 patients were diagnosed with breast cancer in our institution, and only three patients developed HHM without bone metastasis. They were all recurrent breast cancer patients with visceral metastases including the lung and the liver. It took no more than 2 months since symptomatic onset to hospitalization because of hypercalcemia. The maximum serum calcium concentrations were 15.0 mg/dL or higher. All patients had symptoms related to hypercalcemia. Treatment of hypercalcemia including hydration, calcitonin, bisphosphonate, and diuretics was initially effective in the three patients. However, two of three cases were eventually fatal because of unsuccessful treatment of breast cancer.

Conclusions

The common features of HHM without bone metastasis in breast cancer patients include acute onset, severe symptomatic hypercalcemia, and presence of visceral metastasis. Treatment of hypercalcemia decreased serum calcium level in a short period, while successful treatment of breast cancer was essential for a long-term management of HHM. This report provides a consideration to help elucidate the pathophysiology and medical care of breast cancer patients with HHM without bone metastasis.

Hypercalcemia due to methadone-induced adrenal insufficiency in a case of oral cancer

A 31-year-old patient of post-surgical recurrent buccal carcinoma (post-chemo and radiotherapy) on multimodal analgesia with methadone, paracetamol and gabapentin presented to pain clinic with occasional bleeding from tumor area and incidental hypercalcemia. The hypercalcemia was attributed to adrenal insufficiency due to methadone, with no other obvious reasons identified for hypercalcemia or adrenal insufficiency. The patient was managed with the change of opioid, regular aseptic wound dressings and management of hypercalcemia with hydration, calcitonin and steroid therapy. Hypercalcemia in a cancer patient can have multiple other causes like hypercalcemia of malignancy and primary or secondary parathyroid carcinoma. A strong clinical suspicion and appropriate battery of tests may be required to arrive at the diagnosis. Prompt management, including identification and management of the primary pathology along with aggressive hydration with hormonal therapy, may prove to be life-saving.

Treatment of malignancy-associated hypercalcemia with cinacalcet: a paradigm shift

Palliation of symptoms related to malignancy-associated hypercalcemia (MAH) is essential and clinically meaningful for patients, given the continued poor prognosis, with high morbidity and mortality associated with this disease process. Historically, agents have been temporizing, having no impact on patient morbidity nor survival. We suggest that cinacalcet can be an efficacious agent to be taken orally, reducing patients' time in the hospital/clinic settings. It is well-tolerated and maintains serum calcium levels in the normal range, while targeted cancer treatments can be employed. This has a direct, major impact on morbidity. Maintaining eucalcemia can increase quality of life, while allowing targeted therapies time to improve survival. Given that our case (and others) showed calcium reduction in MAH, there is promising evidence that cinacalcet can be more widely employed in this setting. Future consideration should be given to studies addressing the efficacy of cinacalcet in calcium normalization, improvement of quality of life, and impact on survival in patients with MAH. Though the exact mechanism of action for cinacalcet's reduction in calcium in this setting is not currently known, we can still afford patients the possible benefit from it.

Multiple actions of parathyroid hormone-related protein in breast cancer bone metastasis

The sequence similarity within the amino-terminal regions of parathyroid hormone (PTH) and PTH-related protein (PTHrP) allows the two to share actions at a common site, the PTH1 receptor. A number of biological activities have been ascribed to actions of other domains within PTHrP. PTHrP production by late stage breast cancer has been shown to contribute to bone metastasis formation through promotion of osteoclast formation and bone resorption by action through PTH1 receptors. There is evidence also for a role for PTHrP early in breast cancer that is protective against tumour progression. No signalling pathway has been identified for this effect. PTHrP has also been identified as a factor promoting the emergence of breast cancer cells from dormancy in bone. In that case, PTHrP does not function through activation of PTH1 receptors, despite having very substantial effects on transcriptional activity of the breast cancer cells. This indicates actions of PTHrP that are non-canonical, that is, mediated through domains other than the amino-terminal. It is concluded that PTHrP has several distinct paracrine, autocrine, and intracrine actions in the course of breast cancer pathophysiology. Some are mediated through action at PTH1 receptors and others are controlled by other domains within PTHrP. LINKED ARTICLES: This article is part of a themed issue on The molecular pharmacology of bone and cancer-related bone diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.9/issuetoc.

Effects of Serum Albumin, Calcium Levels, Cancer Stage and Performance Status on Weight Loss in Parathyroid Hormone-Related Peptide Positive or Negative Patients with Cancer

BACKGROUND

A recent animal study showed that parathyroid hormone-related peptide (PTHrP) is associated with cancer cachexia by promoting adipose tissue browning, and we previously demonstrated that PTHrP predicts weight loss (WL) in patients with cancer. In this study, we investigated whether prediction of WL by PTHrP is influenced by clinical factors such as serum albumin, corrected calcium levels, cancer stage, and performance status (PS).

METHODS

A cohort of 219 patients with cancer whose PTHrP level was measured was enrolled and followed for body weight (BW) changes. Subjects were divided into two groups by serum albumin (cutoff value, 3.7 g/dL), corrected calcium (cutoff value, 10.5 mg/dL), cancer stage (stage 1 to 3 or 4), or PS (Eastern Cooperative Oncology Group 0 to 1 or 2 to 4), respectively. Clinically significant WL was defined as either percent of BW change (% BW) <-5% or % BW <-2% plus body mass index (BMI) <20 kg/m².

RESULTS

After a median follow-up of 327 days, 74 patients (33.8%) experienced clinically significant WL. A positive PTHrP level was associated with a 2-fold increased risk of WL after adjusting for age, baseline BMI, serum albumin, corrected calcium level, cancer stage, and PS. The effect of PTHrP on WL remained significant in patients with low serum albumin, stage 4 cancer, and good PS. Regardless of calcium level, the effect of PTHrP on WL was maintained, although there was an additive effect of higher calcium and PTHrP levels.

CONCLUSION

Early recognition of patients with advanced cancer who are PTHrP positive with hypercalcemia or hypoalbuminemia is needed for their clinical management.

Clinical Characteristics, Causes and Survival in 115 Cancer Patients with Parathyroid Hormone Related Protein-mediated Hypercalcemia

Background

The aim of this study is to determine the proportion of cancers presenting with parathyroid hormone (PTH) related protein (PTHrP)-mediated hypercalcemia, examine the clinical and biochemical characteristics, identify predictive factors for survival. And we also compared those characteristics between solid organ and hematologic malignancy groups.

Methods

Cancer patients with PTHrP-mediated hypercalcemia who were treated at Chonnam National University Hospital in Korea from January 2005 to January 2015 were retrospectively reviewed.

Results

Of all 115 patients, solid organ malignancies were the most common etiology (98 cases, 85.2%), with squamous cell carcinoma (50 cases, 43.4%), adenocarcinoma (27 cases, 23.4%). Interestingly, hepatocellular carcinoma (HCC; 18 cases, 15.7%) and cholangiocarcinoma (11 cases, 9.6%) were much more common causes than other previous reports. Hematologic malignancy was less common (17 cases, 14.8%), with multiple myeloma (9 cases, 7.8%) and non-Hodgkin's lymphoma (5 cases, 4.3%). Overall median survival was only 37 days. There was significant difference in median survival between two groups (35 days for solid organ malignancy and 72 days for hematologic malignancy; P=0.015). Cox regression analysis identified age, the type of malignancy and the time interval of developing hypercalcemia after cancer diagnosis as independent predictive factors for survival time.

Conclusions

PTHrP-mediated hypercalcemia was most frequently caused by solid organ malignancy. However, HCC and cholangiocarcinoma were important causes of PTHrP-mediated hypercalcemia may be due to geographic differences in cancer incidence in Korean population. Age, the type of malignancy and the time interval of developing hypercalcemia after cancer diagnosis were independent poor predictive factors for survival time.

Animal Models of Cancer-Associated Hypercalcemia

Cancer-associated hypercalcemia (CAH) is a frequently-occurring paraneoplastic syndrome that contributes to substantial patient morbidity and occurs in both humans and animals. Patients with CAH are often characterized by markedly elevated serum calcium concentrations that result in a range of clinical symptoms involving the nervous, gastrointestinal and urinary systems. CAH is caused by two principle mechanisms; humorally-mediated and/or through local osteolytic bone metastasis resulting in excessive calcium release from resorbed bone. Humoral hypercalcemia of malignancy (HHM) is the most common mechanism and is due to the production and release of tumor-associated cytokines and humoral factors, such as parathyroid hormone-related protein (PTHrP), that act at distant sites to increase serum calcium concentrations. Local osteolytic hypercalcemia (LOH) occurs when primary or metastatic bone tumors act locally by releasing factors that stimulate osteoclast activity and bone resorption. LOH is a less frequent cause of CAH and in some cases can induce hypercalcemia in concert with HHM. Rarely, ectopic production of parathyroid hormone has been described. PTHrP-mediated hypercalcemia is the most common mechanism of CAH in human and canine malignancies and is recognized in other domestic species. Spontaneous and experimentally-induced animal models have been developed to study the mechanisms of CAH. These models have been essential for the evaluation of novel approaches and adjuvant therapies to manage CAH. This review will highlight the comparative aspects of CAH in humans and animals with a discussion of the available animal models used to study the pathogenesis of this important clinical syndrome.

Hypercalcemia in the Critically Ill Patient

Hypercalcemia is now frequently recognized in hospitalized patients, including those who are critically ill. Hypercalcemia in critically ill patients may be life threatening or an indication of an underlying but unsuspected disease process. All of the common causes of hypercalcemia can occur in the critically ill patient and are reviewed here. As in the general patient population, the two most common causes are probably malignant disease and primary hyperparathyroidism. Hypercalcemia is now readily reversible in most patients, particularly when the underlying pathophysiologic mechanisms responsible are recognized, and it should be treated actively.

Hypercalcemia of malignancy and new treatment options

Hypercalcemia of malignancy affects up to one in five cancer patients during the course of their disease. It is associated with both liquid malignancies, commonly multiple myeloma, leukemia, and non-Hodgkins lymphoma and solid cancers, particularly breast and renal carcinomas as well as squamous cell carcinomas of any organ. The clinical manifestations of hypercalcemia are generally constitutional in nature and not specific to the inciting malignancy. Such physical manifestations can range from malaise to lethargy and confusion. Constipation and anorexia are common. Acute kidney injury is likely the most frequently encountered manifestation of end organ damage. Symptomatology is closely linked to both the absolute elevation of serum calcium levels and the rapidity of calcium rise. The majority of cases are humoral in etiology and related to parathyroid hormone-related protein (PTHrP). Approximately 20% of cases are the result of direct bone metastasis with extra-renal 1,25-dihydroxyvitamin D (calcitriol) and ectopic parathyroid hormone production likely accounting for less than 1% of cases. The diagnosis of hypercalcemia of malignancy is confirmed either by an elevated PTHrP or by an evidence of bone metastasis in the appropriate clinical setting. Treatment is predicated on the patient’s symptoms and absolute serum calcium level. Interventions are aimed at lowering the serum calcium concentration by inhibiting bone resorption and increasing urinary calcium excretion, the former accomplished via bisphosphonate therapy and the latter with aggressive hydration. Novel therapies for refractory disease include denosumab, a monoclonal antibody against the receptor activator of nuclear factor κB ligand, and the calcimimetic cinacalcet. Finally, anti-PTHrP antibodies have been successfully deployed in animal models of disease. Despite the efficacy of the above therapies, hypercalcemia of malignancy portends an ominous prognosis, indicating advanced and often refractory cancer with survival on the order of months.

At the crossroads: EGFR and PTHrP signaling in cancer-mediated diseases of bone

The epidermal growth factor receptor is a well-established cancer therapeutic target due to its stimulation of proliferation, motility, and resistance to apoptosis. Recently, additional roles for the receptor have been identified in growth of metastases. Similar to development, metastatic spread requires signaling interactions between epithelial-derived tumor cells and mesenchymal derivatives of the microenvironment. This necessitates reactivation of developmental signaling molecules, including the hypercalcemia factor parathyroid hormone-related protein. This review covers the variations of epidermal growth factor receptor signaling in cancers that produce bone metastases, regulation of parathyroid hormone-related protein, and evidence that the two molecules drive cancer-mediated diseases of bone.

Mechanisms and treatment of hypercalcemia of malignancy

PURPOSE OF REVIEW

Hypercalcemia of malignancy is a common paraneoplastic syndrome and a frequent complication of advanced breast and lung cancer, and multiple myeloma. The development of this malignancy complication often purports a poor prognosis. Thorough evaluation to establish the cause of hypercalcemia is essential because some patients may actually have undiagnosed primary hyperparathyroidism.

RECENT FINDINGS

Production of humoral factors by the primary tumor, collectively known as humoral hypercalcemia of malignancy (HHM), is the mechanism responsible for 80% of cases. The vast majority of HHM is caused by tumor-produced parathyroid hormone-related protein followed by infrequent tumor production of 1,25-dihydroxyvitamin D and parathyroid hormone. The remaining 20% of cases are caused by bone metastasis with consequent bone osteolysis and release of skeletal calcium. Key therapies are saline hydration to promote calciuresis and bisphosphonates to reduce pathologic osteoclastic bone resorption. Calcitonin and glucocorticoids, especially in 1,25-dihydroxyvitamin D-mediated HHM, also have calcium-lowering effects.

SUMMARY

Recent discoveries on mechanisms of malignancy-associated hypercalcemia highlight the critical role of the osteoclast. Bisphosphonates and other novel therapies being evaluated in clinical trial target this bone-resorbing cell type and provide effective and durable serum calcium reduction.

Haematological emergencies managing hypercalcaemia in adults and children with haematological disorders

Hypercalcaemia is a common metabolic complication of malignant disease often requiring emergency intervention. Although it is more frequently associated with solid tumours, malignancy-associated hypercalcaemia (MAH) is seen in a significant number of patients with blood diseases. Its association with myeloma and adult T-cell leukaemia/lymphoma is well recognized but the incidence of hypercalcaemia in other haematological neoplasms, affecting adults and children, is less clearly defined. Haematologists need to be familiar with the clinical manifestations of, the differential diagnosis to be considered and the most effective management strategies that are currently available for MAH. The key components of management of MAH include aggressive rehydration, specific therapy to inhibit bone resorption and, crucially, treatment of the underlying malignancy. Bisphosphonates have revolutionized the management of MAH over the last 20 years, however the elucidation of molecular pathways implicated in MAH is facilitating the development of more targeted approaches to treatment.

Hypercalcemia in patients of oral squamous cell carcinoma

PURPOSE

This study was performed to measure the total and ionic serum calcium levels and incidence of hypercalcemia in patients with Oral Squamous Cell Carcinoma (OSCC) and its clinical significance and relevance.

MATERIALS AND METHODS

A randomly selected sample of seventy patients of histologically confirmed Oral Squamous Cell Carcinoma (OSCC) at any of the standard clinical stages were included. Fasting blood samples were obtained for measuring serum calcium levels. The elevated values of serum calcium levels were correlated with clinical features of hypercalcemia to draw inference.

RESULTS

Total serum calcium was found to be elevated in 12 patients (17.4%) and serum ionic calcium was elevated in 3 patients (4.29%).

CONCLUSION

The data suggests that hypercalcemia occurred in advanced stages of oral squamous cell carcinoma and its management may be relevant in providing terminal care and prolonging the life span of the patients.

Clodronate treatment in patients with malignancy-associated hypercalcemia

The possibility of reducing symptomatic hypercalcemia and of maintaining total serum calcium concentrations less than 2.8 mmol/l with clodronate (dichloromethylene bisphosphonate) was evaluated in 28 patients with various types of malignant tumors. Four episodes of hypercalcemic crisis with mean serum calcium concentrations of 4.43 mmol/l were controlled within 4-6 days of intravenous clodronate (4 mg/kg BW/day). This was accompanied by a moderate increase in serum creatinine values which, however, returned to pretreatment levels after therapy withdrawal in all but one case. Oral clodronate successfully reduced a mean serum calcium concentration of 3.16 mmol/l in 22 out of 25 patients after 3-12 days (800-3,200 mg/day). After reversal of the hypercalcemias oral clodronate controlled the serum calcium concentration for up to 42 weeks in six out of 15 patients After discontinuation of initial therapy five of seven recurrent hypercalcemias were successfully treated with oral or intravenous clodronate. Hypocalcemia and subjective side-effects were uncommon. It is concluded that clodronate is a valuable clinical tool in the management of patients with malignancy-associated hypercalcemia.

Malignant hypercalcemia--a hospital survey

A hypercalcemia frequency of 1.5% was found in patients with malignant disease attending a large oncological center. Eighty per cent of hypercalcemias were of obvious malignant etiology. Hypercalcemia was most frequent in multiple myeloma, renal carcinoma, squamocellular carcinomas of different sites and breast cancer. Most patients had advanced metastasized disease. In 80% of those with solid tumors malignant hypercalcemia was associated with bone metastases. Serum calcium could almost invariably be reduced by treatment, and active treatment was associated with a more favorable prognosis. One year actuarial survival of patients with malignant hypercalcemia was 31%.

A hospital survey of hypocalcemia in patients with malignant disease

Hypocalcemia was found in 122 (1.6%) of the patients attending a large oncological center. In 10% of the cases, hypocalcemia was caused by hypoparathyroidism and/or uremia, in 12% it was related to a major infection. Osteoblastic metastases were responsible in 4% of the cases and in 74% hypocalcemia accompanied an impairment of the general condition due to the malignancy or its treatment, usually in the terminal stage of the disease. The most common cause of hypocalcemia in this group of patients seemed to be hypoproteinemia. Correction of serum calcium for variations in serum albumin concentration, however, indicated that a small proportion had a decreased ionized calcium value as well, the mechanism of which remained obscure. The hypocalcemia was usually relatively mild, especially after correction for albumin variations. Tetanic symptoms were not seen. Hypocalcemia thus seems to be a fairly common complication of malignant disease, the clinical relevance of which, however, appears to be relatively small in most cases.

Best practice in primary care pathology: review 11

This eleventh best practice review examines two series of common primary care questions in laboratory medicine: (i) thyroid testing, and (ii) hypercalcaemia and hypocalcaemia. The review is presented in the same question-answer format as in the previous reviews. These questions and answers deal with common situations in men and non-pregnant women. The recommendations represent a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents and evidence-based medicine reviews, supplemented by Medline Embase searches to identify relevant primary research documents. In the case of the thyroid series, the recommendations are drawn from the 2006 guidelines published by the Association for Clinical Biochemistry, the British Thyroid Association and the British Thyroid Foundation. They are not standards but form a guide to be set in the clinical context. Most are consensus rather than evidence based. They will be updated periodically to take account of new information.

Inhibition of epidermal growth factor receptor signalling reduces hypercalcaemia induced by human lung squamous-cell carcinoma in athymic mice

The purpose of this study was to evaluate the role of the epidermal growth factor receptor (EGFR) in parathyroid hormone-related protein (PTHrP) expression and humoral hypercalcaemia of malignancy (HHM), using two different human squamous-cell carcinoma (SCC) xenograft models. A randomised controlled study in which nude mice with RWGT2 and HARA xenografts received either placebo or gefitinib 200 mg kg⁻¹ for 3 days after developing HHM. Effectiveness of therapy was evaluated by measuring plasma calcium and PTHrP, urine cyclic AMP/creatinine ratios, and tumour volumes. The study end point was at 78 h. The lung SCC lines, RWGT2 and HARA, expressed high levels of PTHrP mRNA as well as abundant EGFR protein, but very little erbB2 or erbB3. Both lines expressed high transcript levels for the EGFR ligand, amphiregulin (AREG), as well as, substantially lower levels of transforming growth factor-α (TGF-α), and heparin binding-epidermal growth factor (HB-EGF) mRNA. Parathyroid hormone-related protein gene expression in both lines was reduced 40–80% after treatment with 1 μM of EGFR tyrosine kinase inhibitor PD153035 and precipitating antibodies to AREG. Gefitinib treatment of hypercalcaemic mice with RWGT2 and HARA xenografts resulted in a significant reduction of plasma total calcium concentrations by 78 h. Autocrine AREG stimulated the EGFR and increased PTHrP gene expression in the RWGT2 and HARA lung SCC lines. Inhibition of the EGFR pathway in two human SCC models of HHM by an anilinoquinazoline demonstrated that the EGFR tyrosine kinase is a potential target for antihypercalcaemic therapy.

The causes of hypercalcemia in Okinawan patients: an international comparison

OBJECTIVE

Our objective was to determine the causes and relative prevalence of hypercalcemia in patients at a major community hospital in Okinawa, Japan. Additionally, we compared these causes of hypercalcemia with the previously published international data.

MATERIALS AND METHODS

We analyzed all patients with hypercalcemia in a community teaching hospital in Okinawa, Japan, from 1999 to 2002 and determined the cause of hypercalcemia in each patient. We also performed a literature review of the original articles describing causes of hypercalcemia in patients from Eastern as well as Western countries.

RESULTS

We identified 145 patients with hypercalcemia (median age, 69; range, 22 to 97). Major causes included malignant disorders (n=100; 69%), primary hyperparathyroidism (n=31; 21%), vitamin D-induced (n=4; 3%), and miscellaneous or unknown cause in 11 (8%). Among malignant disorders, adult T cell leukemia was the most frequent (n=35), being followed by lung cancer (n=25). Breast carcinoma was less prevalent (n=4).

CONCLUSION

The major causes of hypercalcemia are malignancy and primary hyperparathyroidism in Okinawan Japanese patients. Adult T cell leukemia and lung carcinoma are among the top leading malignancies, while breast carcinoma is less frequent in this patient population. The etiologic prevalence of hypercalcemia in the Eastern population including Okinawans is significantly different from that in the Western population.

Congenital Craniopharyngioma and Hypercalcemia Induced by Parathyroid Hormone-Related Protein

OBJECTIVE

To report a case of congenital craniopharyngioma and parathyroid hormone-related protein (PTHrP)-associated humoral hypercalcemia.

METHODS

Details of this unusual case are reviewed, from detection of fetal hydrocephalus and a brain tumor, through cesarean delivery at 36 weeks of gestation, to subsequent laboratory studies, management, and confirmation of the diagnosis.

RESULTS

Although PTHrP has been well documented as a cause of humoral hypercalcemia of malignancy (HHM) in adult patients with cancer, HHM is uncommon in children. In addition, HHM has rarely been ascribed to nonmalignant tumors. To the best of our knowledge, we report the first case of a neonate with congenital craniopharyngioma and refractory hypercalcemia (peak ionized calcium level of 1.92 mmol/L; normal, 1.05 to 1.3) attributed to an elevated PTHrP value of 8.6 pmol/L (normal, less than 4.7). Intact parathyroid hormone was appropriately undetectable (less than 10 pg/mL; normal, 15 to 65). Despite calcitonin treatment, the hypercalcemia persisted. Although pamidronate infusion stabilized the serum calcium level, the baby did not survive.

CONCLUSION

The diagnosis of craniopharyngioma was confirmed at autopsy, and immunohistochemical studies substantiated that the craniopharyngioma produced PTHrP.

Hypercalcaemia in relapsed medulloblastoma 8 years post-diagnosis; evidence to support PTHrP production by medulloblastoma cells

BACKGROUND

A 19-year-old male presented with symptomatic hypercalcaemia as the first manifestation of relapsed metastatic medulloblastoma. Management at the time of the initial presentation 8 years earlier was with surgical excision and craniospinal radiotherapy. His biochemistry at the time of relapse and studies of medulloblastoma cell lines provide an insight into the pathogenesis of his hypercalcaemia.

METHODS

Parathyroid hormone-related protein (PTHrP) was measured by immunoradiometric assay in blood, and in conditioned and control media from three medulloblastoma cell lines following 72 h growth.

RESULTS

The histology at initial presentation (11 years of age) and at the time of relapse (with bone marrow infiltration and widespread bony metastases) demonstrated medulloblastoma. Ionised calcium concentrations at relapse were 2.89 mmol/l and serum PTHrP levels were increased at the same time (2.7 pmol/l; normal range: 0.7-1.8 pmol/l). There was evidence of PTHrP production by one cell line (MHH-MED-8A) while results for both other lines tested were below the limit of detection.

CONCLUSIONS

Relapse 8 years after diagnosis is unusual in medulloblastoma and for this relapse to manifest as hypercalcaemia is also very uncommon. Our investigations suggest that the clinical picture was a reflection of PTHrP production by medulloblastoma cells.

Parathyroid hormone-related protein-secreting uterine endometrioid adenocarcinoma

The diagnosis of parathyroid hormone-related protein (PTHrP)-secreting metastatic uterine endometrioid cancer was made in a 32-year-old Japanese woman with humoral hypercalcemia of malignancy. The primary endometrial cancer had been removed, and the tumor was diagnosed as Grade 1 endometrioid adenocarcinoma with shallow myometrial invasion. Salvage chemotherapy (paclitaxel and calboplatin) was started from 5 months after surgery when recurrent tumors were detected in the peritoneum and liver. Despite the salvage chemotherapy, the tumor progressed and hypercalcemia became evident with elevated PTHrP whereas no bone metastasis was identified. To the best of our knowledge, this is the first reported case of hypercalcemia due to PTHrP secretion in uterine endometrioid adenocarcinoma.

A pilot study of antitumor effect of gallium ethylenediaminetetramethylene phosphonate [Ga(III)-EDTMP] in tumor-bearing rats

The inhibitory effects of gallium ethylenediamine-N,N,N',N'-tetrakismethylene phosphonate [Ga(III)-EDTMP] was studied on a malignant tumor and metastatic bone lesion model induced with Walker carcinosarcoma 256 (WCS 256) in Wistar rats weighing 120 to 135 g. A water-soluble chelate, Ga(III)-EDTMP, was prepared for injection in a tumor-bearing model. Radiographic analysis at 14 days indicated that the bone invasion and osteolysis were markedly reduced in animals treated with Ga(III)-EDTMP. The calculated tumor inhibitory rates were 33.16+/-0.38% at a dosage of 5 mg/kg and 47.75+/-0.74% at 10 mg/kg. Biochemical markers such as serum calcium decreased by 23% (P<.05) and by 31% (P<.01) at dosages of 5 mg/kg and 10 mg/kg, respectively, whereas serum alkaline phosphatase (ALPase) activity decreased by 47% (P<.01) and 69% (P<.01) at the 2 dosages.

Increased Renal Calcium Reabsorption by Parathyroid Hormone–Related Protein Is a Causative Factor in the Development of Humoral Hypercalcemia of Malignancy Refractory to Osteoclastic Bone Resorption Inhibitors

PURPOSE

Bisphosphonate and calcitonin lower blood calcium in humoral hypercalcemia of malignancy (HHM) by suppressing osteoclastic bone resorption, but repeated administration of these drugs often leads to relapse. In this study, we examined the roles of parathyroid hormone-related protein (PTHrP) in the development of bisphosphonate- and calcitonin-refractory HHM.

EXPERIMENTAL DESIGN

Nude rats bearing the LC-6 JCK tumor xenograft (LC-6 rats) exhibited high bone turnover and HHM. Repeated administration of alendronate induced a sustained suppression of the bone resorption, but it caused only early and transient reduction of the blood calcium levels, leading to unresponsiveness to the drug. Because high blood levels of PTHrP were detected in the LC-6 rats, those that developed alendronate-refractory HHM were treated with an anti-PTHrP antibody.

RESULTS

Administration of anti-PTHrP antibody to animals that received repeated administration of alendronate, thereby developing alendronate-refractory HHM, resulted in an increase in fractional excretion of calcium and a marked decrease of blood calcium level. Drug-refractory HHM was also observed in animals that received another osteoclast inhibitor, an eel calcitonin analogue elcatonin. The blood calcium level decreased after the initial administration of elcatonin, but it eventually became elevated during repeated administration. Administration of the anti-PTHrP antibody, but not of alendronate, effectively reduced the blood calcium of the animals that developed elcatonin-refractory HHM.

CONCLUSION

High levels of circulating PTHrP and the resulting augmentation of renal calcium reabsorption is one of the major causes of the emergence of osteoclast inhibitor-refractory HHM. Thus, blockage of PTHrP functions by a neutralizing antibody against PTHrP would benefit patients who develop bisphosphonate- or calcitonin-refractory HHM.

Parathyroid hormone and related peptides for the treatment of postmenopausal osteoporosis

Osteopenia, a skeletal condition characterised by bone loss, affects over 10% of the North American population, with a worldwide incidence of 200 m. In the absence of treatment, osteopenia usually progresses to osteoporosis, characterised by more severe bone loss and, ultimately, by fractures. In the US alone osteoporosis affects more than 25 m people, and causes more than 1.3 m fractures a year. This skeletal deterioration is accelerated subsequent to menopause and thus can affect women at a relatively young age. Treatment of postmenopausal osteoporosis primarily involves the use of hormones (calcitonin, oestrogen) or organic molecules (bisphosphonates) which are able to prevent skeletal loss through inhibition of osteoclastic bone resorption. While this may be adequate prior to significant skeletal deterioration and fractures, the patient who has already lost large amounts of bone, in the presence or absence of fractures, requires more aggressive therapy to rapidly rebuild the skeleton. There is now substantial evidence that parathyroid hormone (PTH) is an agent capable of reversing such skeletal loss characteristic of osteoporosis. Numerous animal studies, in conjunction with investigator-initiated clinical trials, have demonstrated the anabolic effects of PTH and related peptides in osteoporotic conditions associated with lack of oestrogen. Large, well-controlled clinical trials are underway to evaluate the safety and efficacy of PTH and PTH-like peptides in postmenopausal osteoporosis. The addition of these agents to the clinician's armamentarium should provide more effective treatment of this condition, thereby preventing the fractures and debilitation that frequently accompany osteoporosis.

Perioperative issues in patients with cancer

The perioperative care of patients with cancer can be an exciting challenge. The physician must consider many factors, including the cancer diagnosis, the extent of disease, treatment received, the presence of comorbid conditions, and the patient's prognosis and must understand the impact of these factors on the planned surgical procedure. In this setting, the physician has the opportunity to perform an essential role in the perioperative management of patients with cancer.

Parathyroid hormone-related protein measured at the time of first visit is an indicator of bone metastases and survival in lung carcinoma patients with hypercalcemia

BACKGROUND

Parathyroid hormone-related protein (PTH-rP) is a major cause of tumor-induced hypercalcemia (TIH) and frequently is found to be elevated in serum of patients with TIH. In the current study, the authors examined the usefulness of PTH-rP measurement at the time of first presentation in the follow-up of lung carcinoma patients with TIH.

METHODS

The authors retrospectively studied 23 of 1149 lung carcinoma patients who were found to have TIH at the time of first presentation for the correlation between serum PTH-rP and the development of bone metastases and survival compared with lung carcinoma patients without TIH who were matched by gender, age, Eastern Cooperative Oncology Group performance status, histological type of tumor, and stage of the disease.

RESULTS

Twenty-three lung carcinoma patients with TIH demonstrated significantly increased serum levels of PTH-rP (mean +/- standard error [SE], 84.1 +/- 16.5 pmol/L) compared with control patients without TIH (mean +/- SE, 36.2 +/- 2.0 pmol/L) at the time of first presentation, (P < 0.001). In these hypercalcemic patients, patients whose serum PTH-rP was > 150 pmol/L (n = 16) were found to have a significantly increased rate of bone metastases (71.4% vs. 12.5%; P = 0.01) and decreased survival (median survival of 1.4 months vs. 5.4 months; P < 0.015) compared with patients whose serum PTH-rP was < 150 pmol/L (n = 7).

CONCLUSIONS

The data from the current study suggest that serum PTH-rP as determined at the time of first presentation is a useful indicator of not only hypercalcemia but also bone metastasis and eventual survival in patients with lung carcinoma.

Treatment of malignant hypercalcaemia

Hypercalcaemia is a common paraneoplastic syndrome caused by the production by tumours of several factors which affect bone resorption and/or tubular calcium reabsorption. Antihypercalcaemic therapy in cancer patients involves rehydration manoeuvres, as well as the use of a variety of available drugs which inhibit bone resorption, namely plicamycin, calcitonin, bisphosphonates and gallium nitrate. While plicamycin is currently out of use because of its considerable toxicity, bisphosphonates have become the standard therapy in hypercalcaemia of malignancy (HM). These compounds are potent inhibitors of bone resorption but they do not affect tubular calcium reabsorption, which limits their efficacy in humoral HM (HHM) cases. In these patients, gallium nitrate should be the therapy of choice. Among the available bisphosphonates, pamidronate administered in a single infusion of 90 mg, normalises serum calcium levels in > 90% of HM patients. A recently introduced bisphosphonate, zoledronate, is likely to replace pamidronate as a first-line therapy in these patients. The effectiveness of calcitonin in HM treatment is limited, although it seems to be useful at the outset in cases with severe symptomatic hypercalcaemia. Future treatment options of HM are likely to include new bone resorption inhibitors, for example, naturally-occurring osteoprotegerin, or alternate approaches aimed at reducing the tumour production of parathyroid hormone-related protein with noncalcaemic analogues of calcitriol or ras-isoprenylation inhibitors. The development of putative therapeutic agents targeted to inhibit distal calcium reabsorption should be valuable in the management of HHM cases.

[Use of disodium pamidronate in patients with bone metastases in patients with pulmonary carcinoma]

Disodium pamidronate (Aredia), a drug of the bisphosphonate group, was administered to 20 patients with pains in the bones due to secondary deposits of lung cancer. The aim of the study was to investigate the analgesic effect of pamidronate to osteolytic metastases of lung cancer in the bone. In 16 (80%) patients non-small-cell lung cancer was diagnosed, and in 4 (20%) patients small-cell-lung cancer was confirmed. Intensive disseminated pains in the bones were present in all the patients. Metastases in the skeleton were confirmed by radiography and scintigraphy of the bones. Initial values of calcium in the plasma were determined in those patients. In 11 (55%) patients, initial values of calcium in the serum were normal, and in 9 (45%) patients, they were elevated. Patients with normal calcium values received 30 mg of pamidronate in 250 ml of normal saline, and patients with hypercalcemia received 45-60 mg in 500 ml of normal saline. Analgesic effect of pamidronate was present in 12 (60%) patients, and the completely painless state was achieved in 4 out of 12 patients. Evaluation of the pain was done by questionnaire, using a simple, descriptive scale. In all 9 (100%) patients with hypercalcemia, values of calcium in plasma were normalized. Pamidronate exerted favorable analgesic effect in the case of metastases of lung cancer in the bones in more than 50% patients. Satisfactory results were also achieved in the patients non-responsive to palliative therapy by irradiation. This enables the use of opiates in lower doses.

Production of parathyroid hormone-related protein in two new cell lines of renal cell carcinoma

BACKGROUND

Hypercalcemia is the most common of all paraneoplastic syndromes and has been reported to appear in up to 20% of patients with renal cell carcinoma (RCC). Humoral hypercalcemia of malignancy is believed to be induced when parathyroid hormone-related protein (PTHrP) is excessively produced in cancer cells and impairs the homeostasis of serum calcium concentrations.

METHODS

Cancer cells were isolated from a surgical specimen and successfully cultured in a monolayer. The present study describes the establishment and characterization of new cell lines of RCC.

RESULTS

Two different cell lines, designated SMRC-1 and SMRC-3, were established from human RCC, each of which had been continuously secreting PTHrP in vitro. The patient from whom the SMRC-3 cells were obtained was shown to have elevated levels of PTHrP and resultant hypercalcemia. Cultured SMRC-1 was spindle-shaped in morphology. SMRC-3 had pleomorphic polygonal shapes and formed typical epithelial monolayers. Both cell types secreted intact, C-terminal PTHrP and interleukin-6 in the culture medium. Cellular messenger RNA of PTHrP was analyzed by reverse transcriptase-polymerase chain reaction. The SMRC-1 cells showed chromosome numbers ranging from 42 to 47 with consistent structural abnormalities of add(4)(q23~25) and add(6)(q13). The chromosomal analysis of SMRC-3 revealed a modal number of 95 with consistent structural abnormalities of add(1)(p36) and der(1;3)(q10;p10).

CONCLUSIONS

These cell lines could be good models for investigating the mechanism of PTHrP production and the relationship between this hormone and hypercalcemia.

[Hypercalcemia, leukemoid reaction, and thrombocytosis as paraneoplastic presentation of transitional cell carcinoma of the kidney]

The most common etiologies of hypercalcemia are hyperparathyroidism or malignancy, most often of the lung, breast or hematological system, but rarely occur in transitional cell carcinoma. The appearance of this metabolic disorder and other paraneoplastic signs like leukemoid reaction or thrombocytosis is a potential marker for malignant behaviour and poor prognosis in advanced tumours. Simultaneous presentation of that three paraneoplastic signs have only been described in two patients with wellknown bladder carcinoma. Most paraneoplastic syndromes appear only during the late stages of malignancy when the diagnosis has long been established, but sometimes may be an early sign of the malignancy. We describe a case of a previously unknown infiltrating transitional cell carcinoma of the kidney without bony metastasis, that presented itself with hypercalcemia, hyperleukocytosis resembling a leukemoid reaction and thrombocytosis. We think recognizing the paraneoplastic syndrome is very important because it is an alarm sign of malignancy.

Acute spontaneous tumor-lysis syndrome in a pregnant woman with non-Hodgkin's lymphoma

Both non-Hodgkin's lymphoma (NHL) in pregnancy and acute spontaneous tumor-lysis (ASTL) syndrome are rare. Here we present a 32-year-old Egyptian woman in the 27th week of pregnancy, who was admitted with epistaxis, lethargy, vomiting and dehydration. This patient developed ASTL syndrome secondary to undiagnosed NHL, but was not on any medication associated with the syndrome. At 28 weeks, she gave birth to a healthy baby who, unfortunately, died within a few days. To our knowledge, this is the first case of ASTL syndrome in a pregnant woman.

Parathyroid hormone-related peptide in pancreatic neuroendocrine tumours associated with hypercalcaemia

BACKGROUND

Hypercalcaemia is a common paraneoplastic syndrome. In the context of pancreatic neuroendocrine tumours, it is occasionally caused by secretion of parathyroid hormone-related peptide (PTH-rP).

CASE OUTLINES

Two patients are reported in whom persistent hypercalcaemia was traced to a large neuroendocrine pancreatic tumour hypersecreting PTH-rP. Resection of the tumour reduced serum levels of calcium and PTH-rP transiently in each case until the patient developed bulky metastatic disease. A 33-year-old woman remained hypercalcaemic after the removal of all four hyperplastic parathyroid glands had rendered circulating parathormone levels undetectable. Radical distal pancreatectomy was followed over the next 4 years by operative debulking of liver metastases, multiple hepatic artery embolisations, octreotide injections and repeated admissions for intravenous fluid and biphosphonate therapy. A 41-year-old man presented with hypercalcaemia as well as features of somatostatinoma syndrome. Symptomatic improvement after radical distal pancreatectomy was short-lived, and hepatic artery embolisation failed to control his rapidly progressive disease.

DISCUSSION

Malignant hypercalcaemia associated with a neuroendocrine pancreatic tumour hypersecreting PTH-rP is difficult to treat and can be life-threatening. Aggressive surgical treatment is recommended initially, while somatostatin analogues and hepatic artery embolisation are alternative therapeutic options for metastatic disease.

Quantitative studies of bone with the use of 18F-fluoride and 99mTc-methylene diphosphonate

This article discusses methods for quantifying bone turnover based on tracer kinetic studies of the short-lived radiopharmaceuticals 99mTc-MDP and 18F-fluoride. Measurements of skeletal clearance obtained by using these tracers reflect the combined effects of skeletal blood flow and osteoblastic activity. The pharmacokinetics of each tracer is described, together with some of the quantitative tests of skeletal function that have been described in the literature. The physiologic interpretation of quantitative measurements of bone obtained with the use of short half-life radionuclides is discussed, and the advantages and limitations of 99mTc-MDP and 18F-fluoride are compared and contrasted. Currently, 18F-fluoride dynamic positron emission tomography (PET) is the technique of choice for physiologically precise quantitative studies of bone. However, comparable data could probably be obtained by using 99mTc-MDP if methods for single photon emission computed tomography (SPECT) quantitation were improved.

Increased upstream methylation has no influence on the overexpression of the parathyroid hormone-related protein gene in squamous cell carcinoma of the lung

Humoral hypercalcaemia of malignancy (HHM) commonly results from the excessive production of a parathyroid hormone-related protein (PTHrP) by tumours. We have previously shown malignancy is associated with increased DNA methylation in the 5' region of the PTHrP gene. In a series of patients with lung carcinoma and relatively high serum calcium levels, 3 patients showed substantially increased PTHrP gene methylation while 5 patients showed no change in methylation status in this region. Patients showed marked tumour-specific expression of PTHrP through the P1 and P3 promoters with more general tumour and non-tumour expression through the P2 promoter. The lack of potential key regulatory CpG sites in the P1 promoter and the complete demethylation in the P2 and P3 promoters suggests methylation does not influence tumour-specific expression of PTHrP. Although demethylation may be a prerequisite for P2 and P3 expression, the overexpression of the PTHrP gene in cancer cells must be mediated through mechanisms other than DNA methylation.

Hypercalcemia and hypermagnesemia

Hypercalcemia and hypermagnesemia occur infrequently in small animal patients. Specific clinical signs usually do not accompany these electrolyte disorders, and their presence is often recognized only after reviewing serum chemistry profile results. The etiologies, clinical signs, and therapies for each electrolyte disorder are discussed in this article. Treatment of these disorders is aimed at correcting the underlying disease process and enhancing the removal of calcium or magnesium from the body. In severe cases, rescue therapies and resuscitative measures are required to stabilize the patient.

Hypercalcaemia in patients with cancer: aetiology and treatment

Hypercalcaemia is one of the most common disorders occurring in patients with cancer and may have disabling symptoms. The mechanisms underlying hypercalcaemia associated with malignant disease, the symptoms attributable to and the treatment of this disorder are discussed in this paper.

Clinical significance of natural killing activity in patients with advanced lymphoma

Using a newly described analysis of natural killing activity employing an "individual effector/target cell ratio" according to the number of effector cells in blood, we recently determined that patients with spontaneous lymphoma regression had elevated natural killing activity prior to regression. To clarify the clinical significance of natural killing activity in patients with advanced lymphoma, a prospective study was performed at a single institution in 43 untreated patients. Survival was analyzed to detect prognostic variables. Among factors chosen initially by univariate analyses, multivariate analysis selected three prognostic factors: chemotherapy response (P < 0.0001), low-grade lymphoma (P = 0.0005), and natural killing activity (P = 0.0052). Within the chemotherapy response, natural killing activity was a unique correlative factor (P < 0.0001) selected by a multivariate regression analysis using forward selection method. In patients with advanced lymphoma, natural killing activity is a valuable prognostic factor and may also predict the response to chemotherapy.

Hypercalcemia in patients with metastatic renal cell carcinoma: effect of nephrectomy and metabolic evaluation

PURPOSE

The role of nephrectomy in the management of hypercalcemia in metastatic renal carcinoma is not known. Hypercalcemia in patients with renal cell carcinoma frequently mimics primary hyperparathyroidism and has been attributed to tumor secretion of parathyroid hormone related protein. We determined the role of cytoreductive surgery in patients with metastatic renal cell carcinoma and hypercalcemia, identified factors that predict patient benefit from surgery, and evaluated the mechanisms of hypercalcemia in these patients.

MATERIALS AND METHODS

A total of 15 patients with metastatic renal cell carcinoma and hypercalcemia underwent metabolic and laboratory evaluation followed by nephrectomy. Post-operatively they were followed for changes in serum calcium levels. We selected 18 normocalcemic patients with metastatic renal cell carcinoma and 4 normocalcemic patients without renal cancer to serve as control groups for survival and parathyroid hormone related protein expression.

RESULTS

A decrease in serum calcium corrected for albumin occurred in 9 of 11 patients at 1 to 4 weeks after nephrectomy and in 7 of 12 patients at 5 to 16 weeks after nephrectomy. Clinical evaluation supported a parathyroid hormone related protein mechanism of hypercalcemia in 5 of 8 patients. Two patients had evidence of local osteolytic hypercalcemia and 1 had prostaglandin mediated hypercalcemia.

CONCLUSIONS

Nephrectomy temporarily ameliorated hypercalcemia in a subgroup of patients with metastatic renal cancer and hypercalcemia. Parathyroid hormone related protein expression was commonly found to be associated with hypercalcemia. Nonparathyroid hormone related protein mechanisms of hypercalcemia in renal carcinoma may be more common than previously thought.

CpG island methylation and promoter usage in the parathyroid hormone-related protein gene of cultured lung cells

Excessive production of a parathyroid hormone-related protein (PTHrP) by tumours commonly results in the syndrome of humoral hypercalcaemia of malignancy. We have investigated whether epigenetic changes play a role in over-expression of the PTHrP gene, using cultures lung cells as a model system. Study of the methylation status of CpG dinucleotides in the 5' region of the gene showed that in normal cells the CpG island was completely unmethylated. In the lung squamous cell carcinoma cell line, BEN, two-thirds of the CpG island was substantially methylated. RT-PCR analysis showed that this heavy methylation did not prevent expression of any of the three PTHrP gene promoters. This is a surprising finding, since methylation is usually associated with inhibition of gene activity. Methylation of the 5' non-coding region of the PTHrP gene may not play a role in the regulation of adjacent promoters. Alternatively, maintenance of a demethylated state in the 170 bp at the 3' end of the CpG island may be fundamental for the use of PTHrP promoters.