[Terminal medical interventions: psychosocial, medical, ethical and legal aspects]

We give an overview of the available medical solutions to help a patient with refractory symptoms at the end of his life. Patient "competence" must first be evaluated and, even if their diagnosis is difficult, organic mental disorders and depression must be diagnosed and adequately treated to allow a real, personal and honest dialog. Administration of high doses of morphine is frequently used at the end of life not only to fully relieve pain but also to accelerate death, even if this is not clearly stated. This technique is not devoid of hypocrisy and high doses of morphine can have quite unpleasant side effects. Treatment withdrawal or withholding is generally not sufficient to allow a correct end of life. The arrest of ventilation, dialysis, artificial nutrition and even more hydration must often be coupled with techniques inducing unconsciousness, which makes imprecise the limits between such a "passive" ending of life and "active" euthanasia. The technique of terminal sedation, frequently based on the use of midazolam, has been more recently introduced in some palliative care units. Such a "controlled sedation" is supposed to allow a "natural" death by inducing a profound sleep. In opposition with active euthanasia, which allows a quiet and rapid death at a moment chosen by the patient himself, this technique of "sedation" has an undetermined duration, has legal implications which could be viewed as quite similar as the ones of euthanasia, and, moreover, this prolonged agony can be extremely stressful and distressing for the family. Medical-assisted suicide is allowed in The Netherlands under the same conditions as euthanasia. Death is generally obtained after a few hours but the technique is not always successful and the process of death can sometimes be prolonged and uncomfortable. This technique can nevertheless be preferred by some physicians and patients. As compared to active euthanasia, the proportion of medically-assisted suicides (1/6) is low in The Netherlands. Euthanasia is the only technique able to induce a peaceful and rapid death. The proportion of various techniques to actively induce death is probably quite similar in our country than in The Netherlands but, most of the time, these interventions occur at the very end of life when the patient is no longer able to participate in the decision process and thus occur without his explicit request. We think that, as for all medical decisions, the use of one or the other of these various techniques should be selected after a quiet and free discussion between the patient and his physician, preferably in advance and not in a situation of emergency and panic.

Bisphosphonates induce breast cancer cell death in vitro

Breast cancer frequently spreads to bone and is almost always associated with osteolysis. This tumor-induced osteolysis is caused by increased osteoclastic bone resorption. Bisphosphonates are used successfully to inhibit bone resorption in tumor bone disease and may prevent development of new osteolytic lesions. The classical view is that bisphosphonates only act on bone cells. We investigated their effects on breast cancer cells using three human cell lines, namely, MCF-7, T47D, and MDA.MB.231, and we tested four structurally different bisphosphonates: clodronate, pamidronate, ibandronate, and zoledronate. We performed time course studies for each bisphosphonate at various concentrations and found that all four compounds induced a nonreversible growth inhibition in both MCF-7 and T47D cell lines in a time- and dose-dependent manner. The MDA.MB.231 cell line was less responsive. Bisphosphonates induced apoptosis in MCF-7 and cell necrosis in T47D cells. The inhibition of MCF-7 cell proliferation could be reverted almost completely by the benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone (z-VAD-fmk) inhibitor of caspases, suggesting that the apoptotic process observed in the MCF-7 cell line is mediated, at least partly, by the caspase system. Caspase activity was little changed by bisphosphonates in T47D cells and the inhibitor of caspase did not modify bisphosphonates effects. In summary, we found that bisphosphonates inhibit breast cancer cell growth by inducing cell death in vitro. Such effects could contribute to the beneficial role of bisphosphonates in the treatment and the prevention of tumor-induced osteolysis.

Decreased efficacy of bisphosphonates for recurrences of tumor-induced hypercalcemia

Bisphosphonates are now the standard treatment for tumor-induced hypercalcemia (TIH), and pamidronate can normalize serum Ca in at least 90% of the patients treated for the first time. However, there are few data on the treatment of TIH when it recurs, and published results are contradictory. We studied 29 patients with solid tumors, 14 of whom had breast cancer and all of whom were naive to bisphosphonate therapy. They were retreated with pamidronate (median dose 1 mg/kg for both courses) for recurrence of TIH after a median interval of 78 (range 7-297) days. Fourteen of them, 7 of whom had breast cancer, were treated a third time 28 (range 5-79) days after the second course (median dose of pamidronate 1.5 mg/kg). Baseline Ca levels were not significantly different before each course, but the nadirs after each treatment progressively increased, 9.3 +/- 0.2 mg/dl, 10.5 +/- 0.3 mg/dl, and 12.3 +/- 0.4 mg/dl after the 1st, 2nd and 3rd administrations, respectively (P<0.05). The percentage of treatment failures also progressively increased: 10%, 31% and 85% (P< 0.05). This decreased hypocalcemic effect was essentially observed in patients without bone metastases or with tumors other than breast cancer. Thus, in patients without bone metastases, Ca levels did not decrease at all after the 3rd course, whereas the responses were not significantly different between the three courses in patients with bone metastases. Baseline urinary hydroxyproline, a marker of bone resorption, increased progressively from course to course, especially in patients with bone metastases or breast cancer, but this was not the case for parameters of bone formation. There was also a progressive increase in PTHrP levels accompanied by an increase in the number of patients with enhanced kidney reabsorption of Ca and a decrease in the threshold for Pi excretion, which was significant in patients without bone metastases. In conclusion, pamidronate was progressively less efficient when hypercalcemia recurred. This was observed mainly in patients with hypercalcemia of humoral origin. Tumor progression is accompanied by an enhanced release of osteolytic factors, notably PTHrP, that increase bone resorption and enhance kidney calcium reabsorption, especially in patients without bone metastases. When both phenomena occur, the response to bisphosphonates becomes minimal and the usefulness of therapy questionable.

Opioid switch to oral methadone in cancer pain

The occurrence of undesirable side effects due to opioids (delirium, confusion, myoclonus, nausea, emesis) is one of the major complications in the management of pain, especially in chronic cancer pain states. Methadone, as an alternative to morphine, has been proposed in the control of opioid-induced toxicity. Methadone is a synthetic opioid, with mu and delta receptor activity, associated with the capacity to inhibit N-methyl-D-aspartate receptors. Questions have arisen concerning its equianalgesic ratio since its rediscovery over the past few years and are certainly related to its receptor interactions. Aspects of its pharmacology, indications, and switching modalities are discussed here. Opioid rotation is a new tool in the management of cancer pain, deserving more attention.

Current and future directions in medical therapy: hypercalcemia

BACKGROUND

Tumor-induced hypercalcemia (TIH) is essentially due to a marked stimulation of osteoclast-mediated bone resorption. An inhibition of bone formation and an enhanced tubular reabsorption of calcium play an important contributory role. These factors explain why serum calcium often rises rapidly in cancer patients and why high doses of bisphosphonates are needed to normalize bone resorption and to overcome the contributory role of the kidney.

METHODS

The author provides a short review of clinical trials in hypercalcemic cancer patients, with an emphasis on the most recent trials.

RESULTS

Rehydration and bisphosphonates now constitute the standard treatment of TIH. A single-day 1500-mg infusion of clodronate achieves normocalcemia in approximately 80% of the cases. Clodronate also can be given by subcutaneous infusion that can be particularly useful in the palliative setting. A dose of 90 mg of pamidronate achieves normocalcemia in more than 90% of the patients and has a longer-lasting effect than clodronate. Newer more potent bisphosphonates, such as ibandronate and zoledronate, may improve these results, and they certainly will simplify the therapeutic schemes. Ibandronate at the dose of 6 mg normalizes serum calcium in more than 75% of the patients with moderate or severe hypercalcemia. Of note, the same doses of pamidronate and ibandronate, repeated monthly for 1-2 years, have been shown to substantially reduce the skeletal morbidity rate in normocalcemic patients with tumor bone disease. Even lower doses of zoledronate, the most potent bisphosphonate tested so far, are able to correct TIH when administered as a 30-minute infusion.

CONCLUSIONS

Bisphosphonates have become the standard treatment for cancer hypercalcemia. Success is achieved in more than 90% of the cases. Other classes of compounds are being tested for their antiosteoclastic activity, and animal studies suggest that osteoprotegerin could be as efficient and act faster than bisphosphonates.

Protein production by osteoblasts: modulation by breast cancer cell-derived factors

Breast cancer cells (BCC) frequently metastasize to bone where they may cause tumor-induced osteolysis (TIO). While the important eroding role of the osteoclasts in TIO is well admitted, the possibility that BCC and/or osteoblasts activated by tumoral factors could also directly degrade bone matrix in this pathology has been much less investigated. We show here that the net collagen amount produced in vitro by normal human osteoblasts and osteoblast-like cells was significantly reduced by culture medium conditioned by several BCC lines, including three newly isolated ones. There was no evidence for a decrease in collagen synthesis, as assessed by the production of the carboxyterminal propeptide of type I collagen. In contrast, the effect of BCC-derived medium on collagen amount was attenuated by inhibitors of matrix metalloproteinases (MMPs) as well as by tranexamic acid, an inhibitor of the plasminogen conversion to plasmin, while it was abolished in presence of the two kinds of proteinase inhibitors. This osteoblastic protein degradation activity appeared to be attributable to factors secreted by the osteoblasts as well as by BCC. These factors had molecular weights lower as well as higher than 10 kD. Our data suggest that besides the eroding action of osteoclasts, BCC- and osteoblast-derived MMPs and serine proteinases might play a direct role in bone collagen degradation in TIO.

A prospective study on hyponatraemia in medical cancer patients: epidemiology, aetiology and differential diagnosis

The frequency of hyponatraemia varies from less than 1% to more than 40% in series reported from general hospitals. We performed a prospective study to evaluate its incidence and to determine the types of hyponatraemia in a dedicated cancer hospital. All patients admitted to the Department of Medicine were prospectively studied over 11 months. Hyponatraemia was defined as a serum Na level < or =130 mEq/l. Urine and blood samples were collected at baseline, and all consecutive hyponatraemic episodes were studied. One hundred and six patients developed 123 episodes of hyponatraemia. The observed incidence of hyponatraemia was 3.7%. Sodium depletion and syndrome of inappropriate antidiuretic hormone secretion (SIADH) each accounted for almost one third of all aetiologies. Serum urea and uric acid, urinary Na and fractional excretions of Na and urea were most useful for the differential diagnosis. The percentage of deaths observed in the hyponatraemic group, 19.5%, was higher than in the whole cancer population (6.3%) although no death was apparently due directly to hyponatraemia. Hyponatraemia is regularly diagnosed in cancer patients, but it was related to SIADH in only about one third of the cases. A higher mortality was observed in hyponatraemic patients than in normonatraemic patients.

[Involutional osteoporosis in women: therapeutic strategy. Recommendations of the Belgian Bone Club]

Osteoporosis is now considered as a major public health issue and a serious threat for the quality of life of elderly women. Several new compounds are currently marketed for the prevention and treatment of involutional osteoporosis in women. Therefore, it is important to offer to the practitioners pragmatic solutions to be used for the rational management of this disorder. This article is the result of a national consensus offering practical guidelines for the management of osteoporotic patients, based on the current published data.

[Raloxifene (Celvista, Evista)]

The prevention of osteoporotic fractures in post-menopausal women must be viewed in the framework of the treatment of menopause. SERMs ("Selective Estrogen Receptor Modulators") derivative from steroid hormones have estrogenic and antiestrogenic properties according to the substance and the target tissue. Raloxifene is a second generation SERM. It increases bone mass by 1 to 3% according to the measured site and, after 3 years of therapy at the dose of 60 mg per day, it reduces the incidence of vertebral fractures by 30 to 50% if patients have or do not have vertebral fractures before therapy. This drug is approved for the prevention of vertebral fractures in post-menopausal women at increased risk of fractures. A significant reduction in the incidence of hip fractures has not been demonstrated. Raloxifene exerts favorable effects on cardiovascular risk factors but one has to wait for the results of controlled prospective trials before concluding that raloxifene reduces the risk of atherogeniec disease. Preliminary results indicate a substantial reduction of the risk of invasive breast cancer, still to be confirmed. The incidence of vaginal bleeding does not differ from placebo as raloxifene does not stimulate endometrial proliferation. The most serious adverse event, although infrequent, consists in an increase of the relative risk of thromboembolic disease by 3.1 as compared to placebo. Longer term studies are necessary to compare raloxifene with the estrogen replacement therapy and to determine the extra-bone effects.

Calcitonin reserve in different stages of atrophic autoimmune thyroiditis

The objective of this study was to determine the calcitonin (CT) hormone reserve in different severity of atrophic autoimmune thyroiditis (AAT). Forty-eight female patients with AAT were divided into four groups based on basal and peak thyrotropin (TSH) values (after oral thyrotropin-releasing hormone [TRH], free triiodothyronine (FT3) and free thyroxine (FT4) ranging from normal in group 1 to overt hypothyroidism in group 4. All had thyroid antibodies. The control group comprised euthyroid females of comparable age, without thyroid antibodies. Basal CT and CT response to calcium infusion (area under the curve) were investigated as parameters of CT reserve. Basal CT was lower in groups 2 to 4 of patients with AAT (compared to controls), but the difference was not significant. Stimulated CT levels were lower (p < 0.05) in all groups of patients compared to controls, with markedly reduced CT-secretory reserve in group 4. Thyroid antibody concentrations and, basal and postinfusion calcium levels were not significantly different among the various groups. In conclusion CT deficiency (especially stimulated values) occurs in AAT and is more severe in hypothyroid patients than in earlier stages of AAT.

Serum parathyroid hormone-related protein levels and response to bisphosphonate treatment in hypercalcemia of malignancy

The pathogenesis of hypercalcemia of malignancy comprises increased net bone resorption and enhanced renal tubular reabsorption of calcium (Ca). To evaluate the prevalence of an increased renal tubular reabsorption of Ca index [tubular reabsorption of calcium index (TRCaI)] in cancer patients with hypercalcemia and of elevated circulating levels of PTH-related protein (PTHrP), which is recognized as a major mediator of this syndrome, we investigated 315 well rehydrated patients, aged 58.1 +/- 0.7 yr (mean +/- SEM), with hypercalcemia [albumin-corrected plasma Ca (pCa), >2.7 mmol/L] secondary to histologically proven malignancy. Changes in pCa and, therefore, various Ca filtered loads were obtained by different degrees of bone resorption inhibition achieved with a single infusion of the bisphosphonate ibandronate, given at various doses on a randomized, double blind basis. PTHrP was determined at baseline in 147 of the patients and 7 days after bisphosphonate therapy in 73. Before ibandronate therapy, pCa was 3.36 +/- 0.02 mmol/L, mean TRCaI was increased at 3.09 +/- 0.03 mmol/L glomerular filtration rate (GFR; normal, 2.40-2.90), and 65% of patients had TRCaI above 2.90 mmol/L GFR. Mean serum PTHrP levels were 4.9 +/- 0.5 pmol/L (normal, <2.5) and values above the normal range were found in 53% of the patients (76% in lung and upper respiratory tract malignancies). By 7 days after the infusion of ibandronate, a decrease in pCa of 0.69 +/- 0.03 mmol/L (20.0 +/- 0.7%; P < 0.001) and in bone resorption [mean change in fasting urinary Ca, 0.09 +/- 0.04 mmol/L GFR (47.6 +/- 8.6%; P < 0.001) and 14.4 +/- 1.7 nmol/mmol (27.6 +/- 10.6%; P < 0.01) in deoxypyridinoline] was observed. TRCaI was slightly lowered by 0.30 +/- 0.09 mmol/L GFR. Mean changes in PTHrP, 1,25-dihydroxyvitamin D3, and PTH were +0.7 +/- 0.4 (P = NS), +27.6 +/- 3.0 (P < 0.001), and +2.9 +/- 0.8 (P < 0.005) pmol/L, respectively. After ibandronate treatment, the relative risk of relapsing hypercalcemia was particularly increased (3.43-fold) in lung and upper respiratory tract malignancies. These results obtained in a large cohort of patients indicate a significant prevalence of an increased renal tubular reabsorption of calcium index in hypercalcemia of malignancy and a substantial proportion of patients with detectable PTHrP.

A dose-finding study of zoledronate in hypercalcemic cancer patients

Zoledronate is a new heterocyclic imidazole bisphosphonate that is the most potent bisphosphonate administered in humans because it is 100-850 times more potent than pamidronate, according to in vitro or animal models of bone resorption. We conducted an open-label, dose-finding, single-dose phase I study in tumor-induced hypercalcemia (TIH), which has been similarly used as a model to determine the active doses of other bisphosphonates. The primary objective was to determine, with a dose escalation schedule, two nontoxic dose levels of zoledronate able to induce normocalcemia in at least 80% of patients with TIH after rehydration (corrected Ca for albumin levels >/=2.75 mmol/l). Based on estimates of potency, the starting dose was 0.002 mg/kg, and further tested doses were 0. 005, 0.01, 0.02, and 0.04 mg/kg. To obtain a more precise estimate of the response rate, we treated 10 more patients at the highest of the two effective dose levels. The median infusion time of zoledronate was 30 minutes. Thirty out of the 33 treated patients were evaluable for efficacy. Thirty percent of the patients had breast cancer and 54% had metastatic bone involvement. For all groups combined, mean Ca levels at baseline was 3.0 mmol/l. The two effective dose levels were 0.02 mg/kg and 0.04 mg/kg. Five out of five patients became normocalcemic after 0.02 mg of zoledronate/kg and 14 out of 15 after 0.04 mg of zoledronate/kg. The success rate of the latter dose was thus 93% (95% confidence interval [CI] 68-100%). At this dose, the first day of normocalcemia was day 2 or 3 for all but one patient. The duration of normocalcemia for the two effective doses could be assessed in nine patients; seven patients remained normocalcemic throughout the trial (32-39 days). The fall in serum Ca was accompanied by a marked fall in fasting urinary Ca excretion. Zoledronate was well tolerated: 7 out of 33 patients developed transient hypophosphatemia, and 3 developed transient hypocalcemia. The only clinically detectable side effect was an increase in body temperature occurring in 10 (30%) patients. In summary, very low doses of zoledronate (0.02 mg/kg and 0.04 mg/kg, i. e., 1.2 mg and 2.4 mg for a 60-kg individual, respectively) administered by a short-time infusion effectively treated patients with TIH. The fall in serum Ca was rapid, and normocalcemia was often maintained for several weeks. Zoledronate was well tolerated. Future trials will determine whether prolonged treatment with this potent compound can have greater effects on the skeletal morbidity rate in patients with tumor bone disease than can be achieved with currently available bisphosphonates.

Metabolic sequelae of cancers (excluding bone marrow transplantation)

The pathogenesis of cancer anorexia/cachexia is still unclear, partly explaining why its treatment remains disappointing. Anorexia plays a central role but cancer cachexia is more complex than chronic starvation. One of the key differences is the preferential mobilization of fat and the sparing of skeletal muscle in simple starvation compared to an equal mobilization of fat and skeletal muscle in cancer patients. An increase in basal energy expenditure also appears to play a contributory role in many patients. Cytokines, essentially but not exclusively tumor necrosis factor-alpha, play an essential pathogenic role and the syndrome can be compared to a low grade chronic inflammatory state. Parenteral nutrition could facilitate the administration of complete doses of chemotherapy or radiotherapy but no significant survival benefit or decrease in treatment-induced toxicity have been demonstrated in prospective randomized trials. The gut should have the preference for nutritional support. Percutaneous endoscopic gastrostomy is used more and more often in patients with a functionally intact gastrointestinal tract, especially in patients with head and neck cancer. Progestational drugs can to some extent stimulate appetite, food intake, energy level, increase weight and decrease the severity of nausea and vomiting. However, pharmacological treatment of cancer cachexia remains disappointing and more trials with anticytokine drugs, anabolic agents or polyunsaturated fatty acids should be conducted.

Assessment of dyspnea in advanced cancer patients

Dyspnea, which has been defined as an "uncomfortable awareness of breathing," is a frequent and devastating symptom in advanced cancer patients. It has been reported to occur in 21-79% of patients evaluated a few days or weeks before death. In advanced cancer, the aim of effective management is to minimize the patient's perception of breathlessness, which depends in turn on a reliable assessment. Unfortunately, most of our knowledge and experience of dyspnea has been acquired through working with patients with chronic pulmonary disease, and there is a dearth of literature relating specifically to the assessment of dyspnea in advanced cancer. Dyspnea is a complex sensation including several dimensions, such as antecedents (physiological and psychological events or stimuli preceding the development of dyspnea), mediators (characteristics of individuals or their environment affecting the response), reactions to dyspnea, and consequences or outcomes that result once the individual has reacted to a stimulus. The literature gives us many tools to measure these aspects. For example, antecedents may be assessed by the British Medical Research Council Questionnaire, the American Thoracic Questionnaire (ATS-DLD-78) and the Dyspnea Interview Schedule. Mediators of dyspnea may be measured by the ATS-DLD-78, the Chronic Respiratory Questionnaire (CRQ), the Dyspnea Interview Schedule, the Pulmonary Functional Status Scale (PFSS) and the Therapy Impact Questionnaire (TIQ). Reactions to dyspnea may be assessed by the Dyspnea Visual Analogue Scale (DVAS), the TIQ and the Borg Scale, and the consequences of it by the TIQ, the Baseline Dyspnea Index (BDI), the Transition Dyspnea Index (TDI), and CRQ, and by the Oxygen Cost Diagram (OCD), the Dyspnea Interview Schedule and the Modified Medical Research Council Dyspnea Scale (MRC). No single assessment tool considers all the different components of dyspnea, and the final choice will depend on the purpose of the assessment, taking into account that the provision of quality of life is of paramount importance to patients who have limited time left to them and that the assessment should not therefore detract from the quality of life by being overlong, complicated or invasive.

The aspirin metabolite salicylate inhibits breast cancer cells growth and their synthesis of the osteolytic cytokines interleukins-6 and -11

Some epidemiological studies have suggested that aspirin could be a chemopreventive agent against breast cancer. We tested the effects of the aspirin metabolite salicylate (SA) on four (Hs578T, MCF-7, MDA-MB-231, and T-47D) breast cancer cell (BCC) lines in vitro. Two features were studied: the proliferation of BCC and their production of the osteolytic cytokines interleukins-6 (IL-6) and -11 (IL-11) since BCC frequently metastasize to bone and induce tumor-induced osteolysis. SA, from 0.5 to 5 mM, caused BCC growth inhibition by up to 70% (IC50 range 2.54 to 4.28 mM). At high concentrations, the drug induced apoptosis only (MDA-MB-231), or both apoptosis and primary necrosis (MCF-7). SA, as well as indomethacin (INDO), reduced the synthesis of IL-6 and -11, at both the protein and mRNA levels, in the two cell lines producing these cytokines (MDA-MB-231 and Hs578T). This latter effect seemed to be mediated by PGE2 since SA and INDO reduced PGE2 levels in MDA-MB-231 and Hs578T cells, PGE2 was not detected in MCF-7 and T-47D cells and exogenous PGE2 increased IL-6 and -11 expression by MDA-MB-231 cells. Collectively, our results suggest that SA could reduce the growth of breast tumors and inhibit to some extent the ability of BCC to induce osteoclast recruitment and osteolysis. These data indicate the need for further epidemiological and experimental studies.

The syndrome of anorexia-cachexia

Cancer anorexia/cachexia is a major clinical problem, especially in advanced cancer patients. Its pathogenesis is quite complex. Anorexia plays a central role, but cancer cachexia is more complex than pure chronic starvation. One of the key differences is the preferential mobilization of fat and the sparing of skeletal muscle in simple starvation compared with an equal mobilization of fat and skeletal muscle in cancer patients. An increase in basal energy expenditures seems to play a contributory role in many patients. Cytokines, essentially but not exclusively tumor necrosis factor alpha, play an essential role, and the syndrome can be compared with a low-grade chronic inflammatory state. As it is in most fields in medicine, prevention is more efficacious than treatment, and, to avoid the final and dramatic stages of cancer cachexia, adequate nutritional advice and support must be provided sufficiently early. Parenteral nutrition could facilitate the administration of complete doses of chemotherapy or radiotherapy, but no significant survival benefit or decrease in treatment-induced toxicity have ever been demonstrated in prospective randomized trials. The gut should always be used if at all possible. Percutaneous endoscopic gastrostomy is used increasingly in patients who cannot eat but who have functionally intact gastrointestinal tracts, especially in patients with head and neck cancer. Eight randomized, double-blind, placebo-controlled studies have demonstrated that progestational drugs can somewhat stimulate appetite, food intake, and energy level; increase weight in many patients; and often decrease nausea and vomiting severity; however, pharmacologic treatment of cancer cachexia remains disappointing, and more trials with anticytokine drugs should be conducted.

Current use of bisphosphonates in oncology. International Bone and Cancer Study Group

PURPOSE

The purpose of this article is to review the recent data on bisphosphonate use in oncology and to provide some guidelines on the indications for their use in cancer patients.

DESIGN

The group consensus reached by experts on the rationale for the use of bisphosphonates in cancer patients and their current indications for the treatment of tumor-induced hypercalcemia and metastatic bone pain in advanced disease and for the prevention of the complications of multiple myeloma and of metastatic bone disease are reviewed.

RESULTS

Bisphosphonates are potent inhibitors of tumor-induced osteoclast-mediated bone resorption. They now constitute the standard treatment for cancer hypercalcemia, for which we recommend a dose of 1,500 mg of clodronate or 90 mg of pamidronate; the latter compound is more potent and has a longer lasting effect. Intravenous bisphosphonates exert clinically relevant analgesic effects in patients with metastatic bone pain. Regular pamidronate infusions can also achieve a partial objective response by conventional International Union Against Cancer criteria and enhance the objective response rate to chemotherapy. In breast cancer, the prolonged administration of oral clodronate 1,600 mg daily reduces the frequency of morbid skeletal events by more than one fourth, whereas monthly pamidronate infusions of 90 mg for only 1 year in addition to chemotherapy reduce by more than one third the frequency of all skeletal-related events. The use of bisphosphonates to prevent bone metastases remains experimental. Last, bisphosphonates in addition to chemotherapy are superior to chemotherapy alone in patients with stages II and III multiple myeloma and can reduce the skeletal morbidity rate by approximately one half.

CONCLUSION

Bisphosphonate use is a major therapeutic advance in the management of the skeletal morbidity caused by metastatic breast cancer or multiple myeloma, although many questions remain unanswered, notably regarding the optimal selection of patients and the duration of treatment.

[Nutritional and digestive disorders in palliative care]

The anorexia-cachexia syndrome is a particularly frequent complication of advanced cancer. Parenteral nutrition must remain the exception in palliative medicine but enteral nutrition through feeding tubes or by a gastrostomy is an efficient method to provide an adequate long term nutritional support at home which can improve the quality of life of the palliative care patient. One must never forget all simple means to improve nutritional status. Since the cost benefit ratio of the medications stimulating the appetite, such as the corticosteroids and the progestatives, must still be demonstrated in palliative medicine. Hiccups therapy is essentially based on several non pharmacological means and on the administration of metoclopramide, antacids, haloperidol or chlorpromazine. Chronic nausea is an extremely frequent problem in palliative care, treated most often by metoclopramide, haloperidol and corticosteroids. Constipation is another extremely frequent problem which can lead to serious complication if left untreated. Besides general means, therapeutic means essentially comprise drugs such as lactulose and macrogol, bisacodyl, docusan and prokinetic agents like cipraside.

[Supportive care: some definitions and principles]

Supportive care is defined as the totality of medical, nursing, psychosocial and rehabilitative support from the onset of the disease until possible fatal outcome, including all active therapeutic phases. This concept is thus quite large and heterogeneous. The term palliative care is reserved for the approach to the terminal patient. Hospital "Palliative Medicine" should be considered as a subspecialty of Internal Medicine and Medical Oncology. In palliative medicine, symptom control, and no longer prolongation of survival, takes a preponderant place to finally become the only goal to reach. In our mind, a Palliative Care Unit is not necessarily the final stay of a patient where spiritual support will be preponderant. One of our essential goals is always that the patient can come back in his family in collaboration with the family doctor, even for a short time. The ideal situation consists in short stays in the Unit to treat an acute complication before the patient is sent back home or to his Residency. Along this line, a very close collaboration with the family doctor is absolutely essential.

[Hypodermoclysis, a neglected approach]

Patients with advanced cancer frequently present with chronic nausea, emesis, bowel obstruction, confusional syndromes or dysphagia. All these conditions make it difficult for the patient to take oral medications or to maintain an adequate level of hydration by mouth. Hypodermoclysis is a safe and simple method that allows for cost-effective sucutaneous delivery of fluids and drugs. Hypodermoclysis has some clearcut advantages over the i.v. route. It can be started without need for a physician or a nurse, does not immobilize a limb, can be stopped and restarted at any moment without concern for clotting, and its use sparses nursing time. It also allows for easier and safer home discharge. Potentiel side effects of hypodermoclysis include pain at infusion site, sloughing tissues as a result of insufficient fluid absorption, infection, and puncture of vessels with bleeding. This paper gives some guidelines for the use of hypodermoclysis for fluid, electrolytes and drugs frequently used in a palliative care setting. The controversy surrounding the treatment of dehydration in the terminally ili is also briefly examined.

[Treatment of cancer pain: the role of co-analgesics]

Opioid analgesics are widely acknowledged as the most important drugs for the treatment of chronic cancer pain. Although these drugs can in most cases control severe pain, even when they are used appropriately, they may produce new symptoms or exacerbate preexisting symptoms, most notably nausea and somnolence. The combination of severe pain, anorexia, chronic nausea, asthenia, and somnolence is a frequent finding in patient with advanced cancer. An adjuvant drug should meet at least one of the following criteria: 1) to increase the analgesic effect of opioids; 2) to decrease their toxicity; 3) to improve others symptoms associated with terminal cancer. Many drugs, such as nonsteroidal antiinflammatory agents, tricyclic antidepressants, corticosteroids, benzodiazepines, amphetamines, antiemetics, oral local anesthetics and bisphosphonates have been suggested to have adjuvant analgesic effects. Unfortunately, most of the evidence for the effects of these drugs is anedoctal. Controlled clinical trials are badly needed to precise the indications and the risk/benefit ratios of these agents, some of which have significant toxicity and could potentially aggravate narcotics toxicity.

Establishment and characterization of three new breast-cancer cell lines

We have established and characterized 3 new breast-cancer cell lines from pleural effusions of patients with advanced breast cancer. All 3 cell lines, designated IBEP-1, IBEP-2 and IBEP-3, showed typical ultrastructural characteristics of epithelial mammary tumor cells. Electron microscopy showed, among other characteristics, the presence of numerous microvilli, desmosomal junctions, intracytoplasmic duct-like vacuoles, well-developed endoplasmic reticulum and large nuclei. Immunohistochemical and biochemical studies revealed that the 3 cell lines expressed cytokeratin, epithelial membrane antigen, CEA and CA 15-3, but all showed negative immunoreaction for vimentin. On the other hand, other antigens (LEU-M1, GCDFP 15, c-erbB-2) were expressed by some of the cell lines, but in a variable manner. Ploidy studies confirmed the neoplastic origin of the cell lines. The doubling times were 68 hr for IBEP-1, 29 hr for IBEP-2 and 39 hr for IBEP-3. Only IBEP-2 cells expressed estrogen receptors (ER+), which were down-regulated after preincubation with E2, but they did not express progesterone receptors (PgR-). IBEP-1 and IBEP-3 cells were ER- but expressed PgR (PgR+). In these 2 cell lines, PgR were down-regulated after pre-incubation of the cells with progesterone (10(-8) M) for 24 hr. Estradiol (E2) increased the proliferation rate of IBEP-2 cells and progesterone increased the proliferation of IBEP-I and -3 cell lines. S.C. injection of the 3 IBEP cell lines into nude mice resulted in the growth of solid tumors between 11 and 16 weeks after inoculation. These cell lines could thus be new models for studying various aspects of the biology and the tumorigenicity of breast-cancer cells. A major interest of these new cell lines is that 2 of them were ER- and PgR+, which is an exceptional phenotypic feature. These 2 cell lines could be interesting models for studying the regulation of PgR and the effects of progestins and antiprogestins independently of the presence of ER.

Production and regulation of interleukin-11 by breast cancer cells

We have studied the production of interleukin-11 (Il-11) in 13 breast cancer cell (BCC) lines. Two of these cell lines (MDA-MB-231 and Hs578T) expressed the cytokine at both the protein and mRNA levels. Il-11 did not modulate the growth of five BCC lines examined, including the two cytokine-producing BCC lines. The production of Il-11 was increased by transforming growth factor-beta1 in a dose-dependent manner with a rapid (2 h) and transient (24 h) mRNA induction, but not by epidermal growth factor, insulin-like growth factor-I and -II, basic fibroblast growth factor, platelet-derived growth factor or parathyroid hormone. The cyclic AMP inducer, forskolin, and the activator of protein kinase C, phorbol 12-myristate 13-acetate, also stimulated the production of Il-11. Besides Il-11, MDA-MB-231 and Hs578T were the only BCC lines to produce interleukin-6 (Il-6) protein and mRNA. Since Il-11 and Il-6 are potent stimulators of osteoclast development and bone is a major source of TGF-beta1, our data suggest that Il-11, together with Il-6, contributes to the high bone destructive capacity of MDA-MB-231 cells and could play a role in breast cancer-induced osteolysis.

[Bone metastases: pathogenesis and treatment with diphosphonates]

Tumor-induced osteolysis is essentially mediated by the osteoclasts whose number and activity appear to be stimulated under the influence of tumor secretory products. In cases of hypercalcemia, there is also a variable inhibition of the bone formation rate leading to a characteristic "uncoupling" in bone turnover. An analog of parathyroid hormone--"parathyroid hormone-related protein (PTHrP)"--plays an essential role in the pathogenesis of neoplastic hypercalcemia. PTHrP concentrations are not regulated by calcium levels which is in marked contrast for PTH. We have also shown that osteoblasts could be essential target cells in the process of tumor-induced osteolysis leading to an increase in osteoclast function and number. From a therapeutic point of view, we have contributed to the optimalization of the therapeutic schemes for tumor-induced hypercalcemia and tumor-induced osteolysis for which the dose of 90 mg of pamidronate appears to be optimal.

Breast cancer cell response to calcitonin: modulation by growth-regulating agents

Calcitonin may induce cyclic AMP production by breast cancer cells and inhibit their growth. The molecular complex leading to cyclic AMP production in response to calcitonin is made of the calcitonin receptor coupled to the adenylate cyclase by at least one guanine nucleotide-binding protein (G-protein, of the Gs type). Our aim was to determine whether and how the responses of cells to calcitonin were modulated by growth-regulating agents not directly acting through the cyclic AMP pathway. We found that the cyclic AMP response to calcitonin was reduced after preincubation of cells with the mitogens 17beta-estradiol and epidermal growth factor (EGF), while it was enhanced after preincubation with the growth inhibitors tamoxifen and 1,25(OH)2D3, as well as with an antisense oligonucleotide to the proto-oncogene c-myc. Scatchard-plots revealed no significant change in the calcitonin receptor number or affinity. On the other hand, the cyclic AMP production of cells in response to activators unrelated to calcitonin, such as forskolin, a direct adenylate cyclase effector, and isoproterenol, a beta-adrenergic receptor agonist, was modulated only weakly or not at all by the growth-regulating agents. This suggested that the effects observed were essentially calcitonin-specific and associated with events located between the calcitonin receptor and the adenylate cyclase. Since a Go- or Gi-protein has been previously implicated in the calcitonin signal transduction, we tested the action of pertussis toxin, a specific inhibitor of these G-proteins. Pertussis toxin produced a general increase in the cyclic AMP response of cells to calcitonin; moreover, the toxin almost abolished the effect of mitogens and antimitogens on that parameter. We conclude that in breast cancer cells, the calcitonin receptor and the adenylate cyclase are coupled by at least one Go/Gi-protein sensitive to growth-regulating agents; this results in a modulation of the cyclic AMP response to calcitonin by these agents. On the other hand, the growth-inhibitory effect of calcitonin on breast cancer cells was reduced by 17beta-estradiol and enhanced by tamoxifen. We suggest that this could be a consequence of changes in cyclic AMP levels and deserves further investigation.

Clinical research update: zoledronate

The prolonged administration of bisphosphonates can reduce the frequency of morbid skeletal events in patients with metastatic breast carcinoma or multiple myeloma. The development of more potent bisphosphonates will simplify current therapeutic schemes and could improve the therapeutic effectiveness of bisphosphonate therapy. Zoledronate (CGP-42446) is the most potent of the clinically tested compounds. It is a cyclic third-generation bisphosphonate that is 100-850 times more active than pamidronate in several in vivo and in vitro pharmacological test systems. The first therapeutic trial with zoledronate has been performed in patients with tumor-induced hypercalcemia (corrected calcium [Ca] > 2.75 mmol/L after rehydration). In a Phase I multicenter trial, it was shown that a single infusion was already effective at dose levels of 0.02 and 0.04 mg of zoledronate/kg bodyweight, thus 1.2 and 2.4 mg total dose for an average 60-kg individual. Five of 5 patients became normocalcemic after a dose of 0.02 mg/kg, and 14 of 15 (93%) after a dose of 0.04 mg/kg. The median time to normalization of serum Ca was 2 days and the median duration of action was 33 days, suggesting that zoledronate has a faster onset and a longer duration of action than other clinically tested bisphosphonates. Zoledronate was well tolerated; the only side effect was an increase in body temperature in 30% of the cases, which was probably not drug-related in many patients. A Phase I trial also has been initiated in patients with lytic bone metastases. Zoledronate was given as monthly short infusions (5-30 minutes) at doses between 0.1-8.0 mg. There was an analgesic effect and even at low doses (2 mg and above), the effects on the biochemical markers of bone resorption appeared to be greater than after 90-mg pamidronate infusions. These initial human data suggest that zoledronate can be administered as convenient short intravenous infusions and lead to a more marked and a more prolonged inhibition of bone resorption than is currently possible with available compounds. Future trials will have to determine whether prolonged treatment with this extremely potent bisphosphonate also can have a greater effect on the morbidity of bone metastases.

The bone isoenzyme of alkaline phosphatase in hypercalcaemic cancer patients

Alkaline phosphatase (AP) is the classic marker of bone formation, especially in cancer patients, but the interpretation of its measurement is complicated by the existence of various circulating isoenzymes, especially of liver origin. The introduction of a mass measurement of the bone isoenzyme of AP (BAP) by an immunoradiometric assay has markedly improved the sensitivity and the specificity of the determination. We measured BAP and other markers of bone turnover in 46 patients with tumour-induced hypercalcaemia (TIH), which is an interesting model for evaluating markers of bone formation because of the uncoupling between bone formation and bone resorption found by histomorphometric techniques. The extent of bone metastatic involvement was evaluated by planimetry on bone scintigraphy. Mean (+/- S.D.) BAP concentrations were slightly higher in patients with TIH than in healthy subjects, 15.5 +/- 8.5 versus 12.4 +/- 3.5 micrograms/L (P < 0.05). However, the scatter of the data in TIH patients was quite marked. Increased values (10/46 patients, 22%) occurred only in patients with bone metastases. Total AP, gamma GT and BGP levels, as well as markers of bone resorption, were not significantly different between patients with or without bone metastases. BAP levels were significantly correlated with AP (rs = 0.63; P < 0.01) but not with BGP levels nor with markers of bone resorption. BAP levels were also correlated with the extent of bone uptake at scintigraphy (rs = 0.54; P < 0.01), but this was not the case for total AP or BGP. In the 36 patients re-evaluated when normocalcemic after pamidronate therapy, BAP levels increased from 16.3 +/- 9.2 to 22.2 +/- 21.3 micrograms/L (P < 0.05) but there were no significant changes in AP or BGP concentrations. In summary, our data confirm the existence of an uncoupling in bone turnover in TIH and indicate that cancer hypercalcaemia is another pathological condition characterised by a discordance between BAP and BGP concentrations. BAP levels appear to be a better reflection of bone metastatic involvement than total AP or BGP and their short-term increase after pamidronate therapy could reflect the recently described effects of bisphosphonates on osteoblasts.

The concept of rehabilitation of cancer patients

The scope of supportive care and cancer rehabilitation is very wide and heterogeneous. In this review we focus on nutritional aspects, sexual and gonadal function, psychological rehabilitation, treatment of cancer pain, and rehabilitation of patients with bone metastases. The anorexia-cachexia syndrome is a particularly frequent manifestation of cancer that profoundly affects body image and significantly impairs quality of life of cancer patients. However, enteral feeding through nasogastric tubes, gastrostomies, or jejunostomies is an efficient method for providing long-term enteral nutrition at home and for contributing to complete rehabilitation after cancer therapy. Recent effort has focused on nutritional pharmacology and on the optimalization of the use of appetite-stimulating drugs, such as progestational agents. The psychological components of cancer, anticancer therapy, and quality of life have now been widely recognized and studied. Effective pharmacological and psychotherapeutic interventions help patients and their family to better adjust to the chronic stress of cancer, but more specific determinants of psychological morbidity should be developed. In particular, the safe and efficient use of the most recent classes of antidepressants and anxiolytics should be urgently studied. More than 90% of cancer patients present one or more pain syndromes during their illness. The adequate use of drugs is the cornerstone of treatment. The development on new molecules and new routes of administration opens interesting perspectives for cancer pain control. Bone metastases are the source of considerable morbidity. Intravenous bisphosphonates have been successfully used for the treatment of the symptoms of metastatic bone disease, especially bone pain. Moreover, monthly pamidronate infusions in addition to chemotherapy reduce the mean skeletal morbidity rate by more than one third and contribute to the rehabilitation of cancer patients with bone metastases from breast cancer or with multiple myeloma.

Regulation of c-fos and c-jun expression by calcitonin in human breast cancer cells

Breast cancer cells (BCC) have calcitonin (CT) receptors, yet the action of the hormone on these cells is largely unknown. We found that CT produced a strong and transient time- and dose-dependent increase in c-fos mRNA in BCC lines. This event was prevented by a protein kinase A (PKA) inhibitor, H89. CT alone did not influence the expression of c-jun and of the tissue inhibitors of metalloproteases (timp) -1 and -2 mRNAs; however, it reduced the induction of these mRNAs by the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA), without apparent changes in the half-life of the mRNA (measured for c-jun). Along the same line, CT reduced the c-jun induction and T-47D growth stimulation by epidermal growth factor (EGF) and insulin. These effects were mimicked by forskolin and/or prevented by H89, suggesting that PKA activation was involved. These results indicate that CT modulates in BCC the mRNA levels of two important growth-related early response genes (c-fos and c-jun) and of two other genes (timp-1 and -2) involved in the control of metastatic events.

Secretory products of breast cancer cells specifically affect human osteoblastic cells: partial characterization of active factors

The pathogenesis of tumor-induced osteolysis (TIO) following breast cancer metastases in bone remains unclear. We postulated that osteoblasts could be target cells for the secretory products of breast cancer cells. We previously showed that serum-free conditioned medium (CM) of the breast cancer cell line MCF-7 inhibits DNA synthesis by 75% of control values in osteoblast-like cells SaOS-2 and that this effect is only in a minor part due to transforming growth factor beta secretion. To establish the specificity of our observations and to look for other biologically active factors, we have tested the effects of medium conditioned by several cancer and noncancer cell lines (breast, colon, placenta, or fibrosarcoma) on the proliferation of osteoblast-like cells (SaOS-2, MG-63), normal human osteoblasts, human fibrosarcoma cells, and normal human fibroblasts. Culture medium (1:2) of the breast cancer cell lines MCF-7, T-47D, MDA-MB-231, and SK-BR-3 inhibited by 25-50% the proliferation of osteoblast-like cells SaOS-2, MG-63, and normal osteoblasts as evaluated by the MTT survival test or [3H]thymidine incorporation. MCF-7 cells completely inhibited the proliferation of normal human osteoblasts in coculture. This inhibitory effect was reversible and not due to cytotoxicity. Moreover, the cyclic adenosine monophosphate (cAMP) response to parathyroid hormone (PTH) of osteoblast-like cells SaOS-2 was also increased by 100-240% by the same CM. Such activities were, however, not detected in medium from the breast noncancer cell line HBL-100 or in the medium conditioned by non-breast cancer cell lines (COLO 320DM, HT-29, JAR, or HT-1080). Medium from the breast cancer cells had no effect on normal human fibroblasts or fibrosarcoma cells (HT-1080), suggesting the specificity of their action on human osteoblasts. After partial purification by ultrafiltration and size-exclusion chromatography, we found that medium of T-47D cells contained at least three nonprostanoid factors of low molecular weights (apparent MW of 700, 1500, and 4000 D) which affected human osteoblast-like cells. These factors were heat stable and could be peptides without disulfide bonds. In summary, our data show that human breast cancer cells release soluble factors that inhibit osteoblast proliferation and increase their cAMP response to PTH, indicating that osteoblasts could be important target cells for breast cancer cells and could be involved in the process of TIO.

Comparative evaluation of markers of bone resorption in patients with breast cancer-induced osteolysis before and after bisphosphonate therapy

The understanding of the pathophysiology and the monitoring of metastatic bone disease remains unsatisfactory. We compared several new markers of bone turnover in normocalcaemic patients with breast cancer-induced osteolysis before and after a single infusion of the bisphosphonate pamidronate. We studied 19 ambulatory patients with advanced breast cancer and extensive bone metastases who did not receive any systemic antineoplastic therapy. Pamidronate was administered at doses of 30, 60, 90 or 120 mg and the patients were followed weekly during a mean of 8 (range 4-10) weeks. Compared with healthy premenopausal women, the percentage of elevated values at baseline was 47% for fasting urinary calcium (uCa), 74% for hydroxyproline, 83% for CrossLaps (a new marker of type I collagen degradation) and 100% for the collagen cross-links (measured by high performance liquid chromatography), namely pyridinoline (Pyr) and deoxyPyr (D-Pyr). Pretreatment levels of uCa did not correlate significantly with any of the four markers of bone matrix resorption, whereas the correlations between these four markers were generally significant (r(s)=0.43-0.71). Alkaline phosphatase correlated significantly with markers of bone matrix resorption (r(s)=0.54-0.74). All parameters, except phosphaturia (uPi) and the bone formation markers (osteocalcin and alkaline phosphatase), fell significantly after pamidronate therapy, up to day 42 for hydroxyproline, D-Pyr and CrossLaps and day 56 for uCa. This longer lasting effect was probably due to the parathyroid hormone (PTH) surge following the decrease in serum calcium, implying that the decrease in uCa can overestimate the effects of bisphophonates on bone resorption. The decrease in bone turnover parameters was most marked for CrossLaps, indicating the potential of this new marker for monitoring therapy. Sequential determinations of markers of bone matrix resorption should be useful in delineating the optimal therapeutic schemes of bisphosphonates and for evaluating treatment effects on bone in cancer patients.

Dose-response study of ibandronate in the treatment of cancer-associated hypercalcaemia

Hypercalcaemia is an important cause of morbidity in malignant disease. We studied the efficacy and safety of intravenous ibandronate (a new, potent bisphosphonate) in a multicentre study of 147 patients with severe cancer-associated hypercalcaemia which had been resistant to treatment with rehydration alone. Of 131 randomized patients who were eligible for evaluation, 45 were allocated to receive 2 mg ibandronate, 44 patients to receive 4 mg and 42 patients to receive 6 mg. Serum calcium values fell progressively in each group from day 2, reaching a nadir at day 5, and in some patients normocalcaemia was maintained for up to 36 days after treatment. The 2-mg dose was significantly less effective than the 4-mg or 6-mg dose in correcting hypercalcaemia, as the number of patients who achieved serum calcium values below 2.7 mM after treatment was 50% in the 2-mg group compared with 75.6% in the 4-mg group and 77.4% in the 6-mg group (P < 0.05; 2 mg vs others). In a logistic regression analysis, three factors were found to predict response; ibandronate dose (higher doses were more effective), severity of presenting hypercalcaemia (severe hypercalcaemia was associated with less complete response) and tumour type (patients with breast carcinoma and haematological tumours responded better than those with other tumours). Ibandronate was generally well tolerated and no serious drug-related adverse events were observed. We conclude that ibandronate is a safe, well tolerated and effective treatment for cancer-associated hypercalcaemia, which should prove a useful addition to the current range of therapies available to treat this condition.

Retrobulbar optic neuritis after pamidronate administration in a patient with a history of cutaneous porphyria

We describe the case of a patient who developed reversible retrobulbar optic neuritis after intravenous pamidronate therapy for established osteoporosis. This possible complication has never been previously reported and, since our patient had a history of porphyria, it suggests that bisphosphonates should be administered cautiously in patients with this disease.

Tumor-induced hypercalcemia in a patient with extensive soft tissue sarcoma: effects of bisphosphonate therapy and surgery

Tumor-induced hypercalcemia (TIH) is a frequent complication of advanced cancer, but it has been rarely reported in patients with sarcoma. We describe the case of a young female patient with TIH and with an extensive synoviosarcoma of the left lower limb destroying the bony structures. Hypercalcemia was severe (18.3 mg/dl) and accompanied by low serum Pi and suppressed parathyroid hormone (PTH) and 1,25(OH)2 vit D3 serum concentrations. Hypercalcemia was successfully treated with ibandronate, a new third-generation bisphosphonate, and radical surgery was performed when the patient was normocalcemic. Circulating levels of PTH-related protein (PTHrP) were elevated at 22.5 pmol/L (NI < 9). PTHrP levels did not change after successful therapy of TIH, in contrast with PTH, which increased sharply. PTHrP levels were normalized after radical surgery. Moreover, low serum Pi with reduced threshold for phosphate excretion and increased tubular calcium reabsorption supported the notion that PTHrP was indeed the essential mediator of paraneoplastic hypercalcemia in this case despite the extensive bone destruction.

Cyclical pamidronate infusions in postmenopausal osteoporosis

OBJECTIVES

Until recently, two bisphosphonates, pamidronate (APD) and etidronate were available for clinical purposes. Contrary to etidronate, pamidronate was not extensively studied in osteoporosis. Therefore, we investigated the effect of cyclic intravenous APD treatment in postmenopausal osteoporosis.

METHODS

Parameters of bone remodelling and lumbar spine bone mineral density (BMDL) were assessed in 36 postmenopausal women with osteoporosis (BMDL t-score < -2.5). They received five courses of APD. Intervals between courses were defined according to the fasting urinary calcium excretion (UCa/Cr, mg/mg creatinine) which was measured before each APD course and every 2 weeks after the first treatment. The patients were retreated when UCa/Cr had reached baseline levels. Serum biochemical parameters and urinary hydroxyproline (UOHPro/Cr, mg/mg) were measured before each APD.

RESULTS

UCa/Cr decreased during 21-28 days after each course but UCa/Cr measured before APD infusion remained unchanged. UOHPro/Cr significantly fell after the third APD (P = 0.02). Serum calcium was however not modified. Parameters of bone remodelling decreased with time: bone-GLA protein (BGP) started to fall after the first APD (P = 0.0001) and continued to decrease until the fourth APD course, alkaline phosphatase (ALP) significantly decreased after the first APD (P = 0.005); intact PTH significantly increased at the fifth APD (P = 0.02). BMDL significantly increased after 1 year treatment: +2.9% of baseline value.

CONCLUSIONS

Cyclical pamidronate treatment of postmenopausal osteoprosis appeared to be effective in reducing bone turnover assessed by BGP, ALP and OHPro/Cr. This effect is followed by an increase in vertebral BMD.

Technical and clinical validation of a new immunoradiometric assay for human osteocalcin

The measurement of circulating osteocalcin or bone GLA protein (BGP) constitutes a well established and non-invasive means for evaluating preferentially the bone formation rate, but most available commercial assays suffer from several technical constraints, notably a rapid degradation of BGP at room temperature or after thawing and the inability to measure subnormal values. We evaluated, from a technical and a clinical viewpoint, a newly available two-site sandwich immunoradiometric assay (IRMA) using standard of human origin and two different monoclonal antibodies. The theoretical and functional assay detection limit was 0.3 ng/ml. Concentrations of BGP progressively decreased when the serum was left at 4 degrees C or at room temperature (mean apparent loss of 15% after 24 h). Two cycles of freezing-thawing only lightly reduced the BGP concentrations. The mean (+/- SD) BGP concentration was 19.6 +/- 7.9 ng/ml in healthy subjects (NI, N = 61); the normal range was 8.1-35.6 ng/ml. There was a marked difference between pre- and postmenopausal women: 15.1 +/- 4.4 vs 22.3 +/- 8.4 ng/ml, respectively (p < 0.05). The mean BGP concentration in patients with tumor-induced hypercalcemia (N = 29) was not significantly different from NI, but nine patients (31%) had subnormal levels and five (17%) had elevated BGP levels. Concentrations of BGP were significantly increased in patients with hyperparathyroidism (N = 14) (45.1 +/- 21.0 ng/ml) and significantly lower than NI in patients with hypoparathyroidism (N = 18) (7.3 +/- 4.6 ng/ml). Concentrations of BGP were also measured by a classical radioimmunoassay using bovine standards and tracer; the correlations between both sets of measurements were significant in all groups, except in patients with hypoparathyroidism. In summary, this newly available IRMA for measuring circulating human BGP appears to be quite sensitive, reproducible and robust. It should be especially useful for investigating clinical conditions characterized by a low bone formation rate.

Effects of secretory products of breast cancer cells on osteoblast-like cells

The pathogenesis of breast cancer-induced osteolysis remains largely unknown. To evaluate the potential role of osteoblasts as target cells during this process, we incubated SaOS-2 human osteoblast-like cells (OBL) with culture media conditioned by proliferative (PM, 'Proliferation Media') or confluent (CfM, 'Confluence Media') MCF-7 human breast cancer cells. CfM decreased the growth of OBL by 26% (P < 0.01) while PM was without significant effect on this parameter. In contrast, both PM and CfM obtained from MCF-7 cultures increased the cyclic AMP (cAMP) response of OBL to the osteolytic agents PTH (10(-8) M) and PTH-related peptide (PTHrP, 10(-8) M) by a factor of about 3 (P < 0.001), and to prostaglandin E(2) (PGE(2),10(-6) M) by a factor of about 2 (P < 0.01). No significant modulation of OBL growth or sensitivity to PTH, PTHrP, or PGE2 was induced by media obtained from HBL-100 non-malignant immortalized breast epithelial cell cultures. 17betaestradiol (E(2), 10(-8) M) and the antiestrogen tamoxifen (Tam, 10(-7) M) added for 48 h to MCF-7 cultures before collecting conditioned media attenuated and potentiated, respectively, the PM- but not the CfM-induced increase in the response of OBL to PTH or PTHrP Along the same line, the addition to MCF-7 conditioned media of a polyclonal anti-transforming growth factor-beta (TGF-beta) antibody attenuated by about 25% (P < 0.01) the PM-induced increase in OBL response to PTH and PTHrP while abrogating the modulatory effects of E(2) and Tam on that response. Together, our results indicate that MCF-7 breast cancer cells secrete factors which inhibit the growth of OBL and increase their sensitivity to various osteolytic agents. TGF-beta was only partly responsible for these effects, and accounts for their modulation by E(2) and Tam. The identification of other osteoblast-modulatory factor(s) should contribute to a better understanding and treatment of breast cancer-induced osteolysis.

Administration of the bisphosphonate ibandronate (BM 21.0955) by intravenous bolus injection

Bisphosphonates (BPs) are used for the treatment of both benign and malignant diseases characterized by increased bone resorption. Because of their potential nephrotoxicity, currently available BPs have to be administered by slow intravenous infusion, with conventional doses requiring an infusion time of at least 2 h. In the present investigation, we evaluated the safety and efficacy of the new BP ibandronate as administered by intravenous bolus injection. On day 0, 15 normocalcemic breast cancer patients with bone metastases were treated with 3 mg of ibandronate injected intravenously over 60-120 s. Ibandronate treatment led to significant decreases in serum levels of calcium (p < 0.0001) and phosphate (p < 0.0001) and to subsequent increases in serum concentrations of parathyroid hormone (p <0.0001) and calcitriol (p <0.0001). Moreover, there was a significant reduction in the urinary excretion of calcium (p <0.0001), pyridinoline (p <0.001), and deoxypyridinoline (p < 0.0001). Three serious adverse events were observed: vomiting (WHO grade 3), pulmonary infection (WHO grade 2), and deterioration of a pre-existing impaired glucose tolerance (WHO grade 3). Only vomiting appeared to be related to administration of the drug. The most frequent nonserious adverse events were 10 cases of transient clinically asymptomatic hypocalcemia and 8 cases of asymptomatic hypophosphatemia. Serum levels of creatinine and urea nitrogen did not increase, nor did creatinine clearance deteriorate. When tested with the dipstick method, proteinuria was present in five (33%) patients prior to ibandronate treatment (median protein concentration, 30 mg/dl). Following the BP injection, seven (47%) patients showed slight (highest protein concentration, 30 mg/dl) transient proteinuria at at least one time point, of which six cases appeared in conjunction with leucocyturia and three with microhematuria. Side effects specific to aminosubstituted BPs (fever, reduction in white blood cell counts, and lymphocyte counts) were not seen in these 15 patients. In conclusion, a single intravenous injection of 3 mg of ibandronate significantly inhibited osteoclast activity as reflected by the decrease in serum calcium and in urinary parameters of bone resorption. Serum creatinine levels and estimates of creatinine clearance were not affected by therapy. However, before repeated bolus injections of ibandronate at this dosage can be recommended for further clinical trials, whether a relationship exists between the transient pathological urinary findings and injected ibandronate needs to be determined.

Randomized phase II trial comparing different doses of the bisphosphonate ibandronate in the treatment of hypercalcemia of malignancy

PURPOSE

To evaluate the hypocalcemic effect and safety of three different doses of the bisphosphonate ibandronate in tumor-associated hypercalcemia, and to identify factors predicting response.

PATIENTS AND METHODS

One hundred seventy-four cancer patients with a serum calcium level greater than 2.7 mmol/L (10.8 mg/dL) were enrolled onto the trial. If hypercalcemia persisted after fluid repletion, patients were randomly assigned to treatment with 0.6 mg, 1.1 mg, and 2.0 mg of ibandronate. Response, defined as restoration of normocalcemia, was evaluated by an intent-to-treat analysis.

RESULTS

One hundred seventy-three (99%) patients were assessable for toxicity and 151 (87%) for efficacy. The administration of 0.6 mg (group A), 1.1 mg (group B), or 2.0 mg (group C) of ibandronate led to response rates of 44%, 52%, and 67%, respectively. Significantly more patients in group C responded than in group A (P = .0276). Of the various parameters examined, only the initial serum calcium level (P < .0001; odds ratio, 0.083) and the dose of ibandronate (P = .0162; odds ratio, 2.094) correlated with response. One hundred ninety-five adverse events (AEs) were reported, 99 classified as serious and 96 as nonserious. Three serious and sixteen nonserious AEs were considered related to ibandronate treatment. The three serious AEs were one case with thrombocytopenia, one with nausea, and one with fever.

CONCLUSION

Ibandronate therapy led to a dose-dependent reduction in serum calcium levels. The response to ibandronate treatment correlated negatively with the initial serum calcium level and positively with the dose administered. A dose of 2 mg was necessary to achieve a response rate comparable to that in previous studies with the bisphosphonates pamidronate and clodronate. Because the incidence of drug-associated AEs was low, a dose escalation of ibandronate can be recommended for further clinical trials.

Clinical trials in metastatic breast cancer to bone: past--present--future

The skeleton is the most common site of metastatic disease in breast cancer and the site of first distant relapse in almost one half of the cases. Bone metastases are the source of a considerable morbidity, including pain, long bone fractures in 10-20%, and hypercalcemia in 10-15% of the cases. The median survival after first relapse in bone is close to two years compared to three months after first relapse in liver. A review of endocrine and chemotherapy trials indicates that patients with metastatic bone disease have a lower response rate to antineoplastic therapy than patients with soft tissue or visceral metastases, but this probably reflects selection bias and the insensitivity of our current methods for evaluating bone response. Classical UICC criteria require radiological recalcification, implying not only tumor regression but also bone healing, which can take many months. Symptom evaluation, measurement of tumor markers and of biochemical parameters of bone turnover should be further investigated for early assessment of bone response. Pain relief could occur in more than half of the patients after radiotherapy, but uncertainty remains as to the relationship between radiotherapy dose or fractionation and the incidence duration of pain relief. Radioactive isotopes have been used successfully in patients with blastic bone metastases from prostate cancer, but controlled studies are lacking in breast cancer. The pathophysiology of metastatic bone destruction makes it logical to use osteoclast inhibitors. Bisphosphonates are potent inhibitors of bone resorption that have opened the way for a noncytotoxic medical treatment of bone metastases. Two large-scale studies in patients with breast cancer metastatic to the skeleton, one with clodronate and one with pamidronate, indicate that the prolonged administration of oral bisphosphonates, in addition to systemic antineoplastic therapy, can reduce the frequency of morbid skeletal events, including the incidence of hypercalcemic episodes and the need for radiotherapy, and probably the incidence of severe pain and of fractures. On the other hand, in patients with established tumor-induced osteolysis, intravenous pamidronate infusions can induce bone pain relief and an objective sclerosis of lytic lesions maybe in one-third and in one-fourth of the cases, respectively. These figures must, however, be taken with caution, and prospective placebo-controlled trials in large series of patients are needed.

Calcitonin for prevention and treatment of postmenopausal osteoporosis

Prolonged calcitonin administration (intramuscular, subcutaneous, or intranasal) can prevent postmenopausal trabecular bone loss. Nasal administration constitutes a particularly attractive option for women who cannot tolerate or benefit from estrogen replacement therapy. The optimal schedule of administration still has to be precised, but 100 U/day of nasal calcitonin, combined with calcium supplements, can currently be recommended. Interrupted regimens are maybe favourable. Calcitonin can also prevent further bone loss in established osteoporosis particularly if bone turnover is increased. The anti-fracture efficacy of calcitonin is suggested by different types of studies but has not been formally demonstrated. Lastly, its analgesic efficacy in cases of painful vertebral compression fractures has been demonstrated in controlled studies.