Ifosfamide nephrotoxicity in pediatric cancer patients

[Electrolyte disorders in oncological patients]

Electrolyte disorders (ED) are common in patients with cancer and in most cases, the etiologies do not differ from the general population. They may also be induced by the cancer, its therapy or paraneoplastic syndromes. ED are associated with poor outcomes, increased morbidity and mortality in this population. Hyponatremia is the most common disorder, often multifactorial, iatrogenic or secondary to the syndrome of inappropriate antidiuretic hormone secretion, usually due to small cell lung cancer. More rarely, hyponatremia may reveal adrenal insufficiency. Hypokalemia is generally multifactorial and associated with other ED. Cisplatin and ifosfamide induce proximal tubulopathies with hypokalemia and/or hypophosphatemia. Hypomagnesemia is often iatrogenic, related to cisplatin or cetuximab, but can be prevented by supplementation. Hypercalcemia can impair life quality and be life-threatening in the most severe cases. Hypocalcemia is less common and often of iatrogenic origin. Finally, the tumor lysis syndrome is a diagnostic and therapeutic emergency that affects the prognosis of patients. Its incidence tends to increase in solid oncology, related to the improvement of therapies. Prevention and early diagnosis of ED are essential to optimize the overall management of patients with underlying cancer and cancer therapy. The aim of this review is to synthesize most frequent ED and their management.

Alkylating agents-induced gonadotoxicity in prepubertal males: Insights on the clinical and preclinical front

Rising cure rates in pediatric cancer patients warrants an increased attention toward the long-term consequences of the diagnosis and treatment in survivors. Chemotherapeutic agents can be gonadotoxic, rendering them at risk for infertility post-survival. While semen cryopreservation is an option that can be provided for most (post)pubertal boys before treatment, this is unfortunately not an option prepubertal in age, simply due to the lack of spermatogenesis. Over the last couple of years, studies have thus focused on better understanding the testis niche in response to various chemotherapeutic agents that are commonly administered and their direct and indirect impact on the germ cell populations. These are generally compounds that have a high risk of infertility and have been classified into risk categories in curated fertility guidelines. However, with it comes the lack of evidence and the challenge of using informative models and conditions most reflective of the physiological scenario, in short, the appropriate study designs for clinically relevant outcomes. Besides, the exact mechanism(s) of action for many of these "risk" compounds as well as other agents is unclear. Understanding their behavior and effect on the testis niche will pave the way for incorporating new strategies to ultimately combat infertility. Of the various drug classes, alkylating agents pose the highest risk of gonadotoxicity as per previously established studies as well as risk stratification guidelines. Therefore, this review will summarize the findings in the field of male fertility concerning gonadotoxicity of akylating agents as a result of chemotherapy exposure.

Hypophosphatemia in cancer patients

Dysregulation of phosphorus homeostasis resulting in hypophosphatemia is common in cancer patients and can result in serious complications and impact outcomes. Several factors, including critical illness, nutritional status, cancer type and therapy, influence the development of hypophosphatemia. Hypophosphatemia can develop as a result of phosphaturic mesenchymal tumors or as a paraneoplastic phenomenon. The clinical presentation for hypophosphatemia varies depending on the duration and severity of the hypophosphatemia and affects several organ systems. Among other serious effects, hypophosphatemia can impair tissue oxygenation and can cause hemolysis, leukocyte and platelet dysfunction, encephalopathy, seizures, arrhythmias, cardiomyopathy, rhabdomyolysis and coma. Multiple studies have demonstrated that hypophosphatemia is an adverse prognostic marker in inpatients with increased in-hospital stay, mortality and postoperative complications. The phosphate level is homeostatically regulated and maintained in a narrow range by three main hormones: parathyroid hormone, fibroblast growth factor 23 and 1,25-dihydroxyvitaminD₃. Together, these hormones regulate how the intestine, kidneys and bones traffic phosphorus. Several hematological malignancies and cancer therapies are associated with proximal tubular dysfunction (Fanconi syndrome), resulting in phosphaturia. Caution should be taken with parenteral administration of phosphate salts, because secondary complications can develop, principally due to hypocalcemia. The general approach to hypophosphatemia should target the underlying cause. Early recognition and prevention are essential and the approach to hypophosphatemia in the cancer patient, because of the nuances and complexity, should be multidisciplinary.

Onconephrology: The intersections between the kidney and cancer

Onconephrology is a new subspecialty of nephrology that recognizes the important intersections of kidney disease with cancer. This intersection takes many forms and includes drug-induced nephrotoxicity, electrolyte disorders, paraneoplastic glomerulonephritis, and the interactions of chronic kidney disease with cancer. Data clearly demonstrate that, when patients with cancer develop acute or chronic kidney disease, outcomes are inferior, and the promise of curative therapeutic regimens is lessened. This highlights the imperative for collaborative care between oncologists and nephrologists in recognizing and treating kidney disease in patients with cancer. In response to this need, specific training programs in onconephrology as well as dedicated onconephrology clinics have appeared. This comprehensive review covers many of the critical topics in onconephrology, with a focus on acute kidney injury, chronic kidney disease, drug-induced nephrotoxicity, kidney disease in stem cell transplantation, and electrolyte disorders in patients with cancer.

Electrolyte Disorders Induced by Antineoplastic Drugs

The use of antineoplastic drugs has a central role in treatment of patients affected by cancer but is often associated with numerous electrolyte derangements which, in many cases, could represent life-threatening conditions. In fact, while several anti-cancer agents can interfere with kidney function leading to acute kidney injury, proteinuria, and hypertension, in many cases alterations of electrolyte tubular handling and water balance occur. This review summarizes the mechanisms underlying the disturbances of sodium, potassium, magnesium, calcium, and phosphate metabolism during anti-cancer treatment. Platinum compounds are associated with sodium, potassium, and magnesium derangements while alkylating agents and Vinca alkaloids with hyponatremia due to syndrome of inappropriate antidiuretic hormone secretion (SIADH). Novel anti-neoplastic agents, such as targeted therapies (monoclonal antibodies, tyrosine kinase inhibitors, immunomodulators, mammalian target of rapamycin), can induce SIADH-related hyponatremia and, less frequently, urinary sodium loss. The blockade of epidermal growth factor receptor (EGFR) by anti-EGFR antibodies can result in clinically significant magnesium and potassium losses. Finally, the tumor lysis syndrome is associated with hyperphosphatemia, hypocalcemia and hyperkalemia, all of which represent serious complications of chemotherapy. Thus, clinicians should be aware of these side effects of antineoplastic drugs, in order to set out preventive measures and start appropriate treatments.

Early and late adverse renal effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Improvements in diagnostics and treatment for paediatric malignancies resulted in a major increase in survival. However, childhood cancer survivors (CCS) are at risk of developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is a known side effect of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate (GFR) impairment, proteinuria, tubulopathy, and hypertension. Evidence about the long-term effects of these treatments on renal function remains inconclusive. It is important to know the risk of, and risk factors for, early and late adverse renal effects, so that ultimately treatment and screening protocols can be adjusted. This review is an update of a previously published Cochrane Review.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with the general population or CCS treated without potentially nephrotoxic treatment. In addition, to evaluate evidence on associated risk factors, such as follow-up duration, age at time of diagnosis and treatment combinations, as well as the effect of doses.

SEARCH METHODS

On 31 March 2017 we searched the following electronic databases: CENTRAL, MEDLINE and Embase. In addition, we screened reference lists of relevant studies and we searched the congress proceedings of the International Society of Pediatric Oncology (SIOP) and The American Society of Pediatric Hematology/Oncology (ASPHO) from 2010 to 2016/2017.

SELECTION CRITERIA

Except for case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment), in CCS treated before the age of 21 years with cisplatin, carboplatin, ifosfamide, radiation involving the kidney region, a nephrectomy, or a combination of two or more of these treatments. When not all treatment modalities were described or the study group of interest was unclear, a study was not eligible for the evaluation of prevalence. We still included it for the assessment of risk factors if it had performed a multivariable analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, 'Risk of bias' assessment and data extraction using standardised data collection forms. We performed analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

Apart from the remaining 37 studies included from the original review, the search resulted in the inclusion of 24 new studies. In total, we included 61 studies; 46 for prevalence, six for both prevalence and risk factors, and nine not meeting the inclusion criteria, but assessing risk factors. The 52 studies evaluating the prevalence of renal dysfunction included 13,327 participants of interest, of whom at least 4499 underwent renal function testing. The prevalence of adverse renal effects ranged from 0% to 84%. This variation may be due to diversity of included malignancies, received treatments, reported outcome measures, follow-up duration and the methodological quality of available evidence.Seven out of 52 studies, including 244 participants, reported the prevalence of chronic kidney disease, which ranged from 2.4% to 32%.Of these 52 studies, 36 studied a decreased (estimated) GFR, including at least 432 CCS, and found it was present in 0% to 73.7% of participants. One eligible study reported an increased risk of glomerular dysfunction after concomitant treatment with aminoglycosides and vancomycin in CCS receiving total body irradiation (TBI). Four non-eligible studies assessing a total cohort of CCS, found nephrectomy and (high-dose (HD)) ifosfamide as risk factors for decreased GFR. The majority also reported cisplatin as a risk factor. In addition, two non-eligible studies showed an association of a longer follow-up period with glomerular dysfunction.Twenty-two out of 52 studies, including 851 participants, studied proteinuria, which was present in 3.5% to 84% of participants. Risk factors, analysed by three non-eligible studies, included HD cisplatin, (HD) ifosfamide, TBI, and a combination of nephrectomy and abdominal radiotherapy. However, studies were contradictory and incomparable.Eleven out of 52 studies assessed hypophosphataemia or tubular phosphate reabsorption (TPR), or both. Prevalence ranged between 0% and 36.8% for hypophosphataemia in 287 participants, and from 0% to 62.5% for impaired TPR in 246 participants. One non-eligible study investigated risk factors for hypophosphataemia, but could not find any association.Four out of 52 studies, including 128 CCS, assessed the prevalence of hypomagnesaemia, which ranged between 13.2% and 28.6%. Both non-eligible studies investigating risk factors identified cisplatin as a risk factor. Carboplatin, nephrectomy and follow-up time were other reported risk factors.The prevalence of hypertension ranged from 0% to 50% in 2464 participants (30/52 studies). Risk factors reported by one eligible study were older age at screening and abdominal radiotherapy. A non-eligible study also found long follow-up time as risk factor. Three non-eligible studies showed that a higher body mass index increased the risk of hypertension. Treatment-related risk factors were abdominal radiotherapy and TBI, but studies were inconsistent.Because of the profound heterogeneity of the studies, it was not possible to perform meta-analyses. Risk of bias was present in all studies.

AUTHORS' CONCLUSIONS

The prevalence of adverse renal effects after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region, nephrectomy, or any combination of these, ranged from 0% to 84% depending on the study population, received treatment combination, reported outcome measure, follow-up duration and methodological quality. With currently available evidence, it was not possible to draw solid conclusions regarding the prevalence of, and treatment-related risk factors for, specific adverse renal effects. Future studies should focus on adequate study designs and reporting, including large prospective cohort studies with adequate control groups when possible. In addition, these studies should deploy multivariable risk factor analyses to correct for possible confounding. Next to research concerning known nephrotoxic therapies, exploring nephrotoxicity after new therapeutic agents is advised for future studies. Until more evidence becomes available, CCS should preferably be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

Paediatric cancer survivors demonstrate a high rate of subclinical renal dysfunction

BACKGROUND

Clinical manifestations of renal dysfunction in childhood cancer survivors include hypertension, proteinuria, tubulopathy (and its biochemical consequences) and renal insufficiency. This study aimed to determine the factors associated with renal dysfunction in paediatric cancer survivors at a single centre in Johannesburg.

PROCEDURE

A descriptive cross-sectional study was performed on 130 cancer survivors between 2 and 18 years of age. Physical examination and screening urine dipstick were performed on all patients. Blood results of samples routinely drawn were analysed.

RESULTS

After a median follow-up period of 2 years, the various manifestations of renal dysfunction included decreased estimated glomerular filtration rate (eGFR), hypomagnesaemia, hypophosphataemia, proteinuria, haematuria and hypertension. In total, 34 survivors (26.15%) had at least one manifestation of renal dysfunction after completing treatment. The most prevalent manifestation of renal dysfunction was decreased eGFR (17.7%) followed by hypomagnesaemia (6.2%) and hypophosphataemia (4.6%). Patients with pre-existing renal dysfunction were three times more likely to have renal dysfunction post-treatment (P = 0.020). Ifosfamide (P = 0.010) and nephrectomy (P = 0.003) had independent significant impact on reduction in eGFR. High cumulative ifosfamide doses were identified as a possible cause for hypophosphataemia (P = 0.021).

CONCLUSION

While not clinically evident in the early follow-up period, the high rate of renal dysfunction is concerning. We suggest that patients with pre-existing renal dysfunction should be assessed by a nephrologist prior to initiation of cancer therapy, and nephro-protective measures should be employed stringently in all children with cancer. Patients with decreased eGFR should be followed up closely in a multidisciplinary late effects clinic.

Electrolyte disorders associated with the use of anticancer drugs

The use of anticancer drugs is beneficial for patients with malignancies but is frequently associated with the occurrence of electrolyte disorders, which can be hazardous and in many cases fatal. The review presents the electrolyte abnormalities that can occur with the use of anticancer drugs and provides the related mechanisms. Platinum-containing anticancer drugs induce hypomagnesemia, hypokalemia and hypocalcemia. Moreover, platinum-containing drugs are associated with hyponatremia, especially when combined with large volumes of hypotonic fluids aiming to prevent nephrotoxicity. Alkylating agents have been linked with the occurrence of hyponatremia [due to syndrome of inappropriate antidiuretic hormone secretion (SIADH)] and Fanconi's syndrome (hypophosphatemia, aminoaciduria, hypouricemia and/or glucosuria). Vinca alkaloids are associated with hyponatremia due to SIADH. Epidermal growth factor receptor monoclonal antibody inhibitors induce hypomagnesemia, hypokalemia and hypocalcemia. Other, monoclonal antibodies, such as cixutumumab, cause hyponatremia due to SIADH. Tyrosine kinase inhibitors are linked to hyponatremia and hypophosphatemia. Mammalian target of rapamycin inhibitors induce hyponatremia (due to aldosterone resistance), hypokalemia and hypophosphatemia. Other drugs such as immunomodulators or methotrexate have been also associated with hyponatremia. The administration of estrogens at high doses, streptozocin, azacitidine and suramin may induce hypophosphatemia. Finally, the drug-related tumor lysis syndrome is associated with hyperphosphatemia, hyperkalemia and hypocalcemia. The prevention of electrolyte derangements may lead to reduction of adverse events during the administration of anticancer drugs.

Aminoaciduria in the prediction of ifosfamide-induced tubulopathy after childhood cancer: a feasibility study

BACKGROUND

Ifosfamide, an alkylating agent used widely in the treatment of childhood malignancy, can cause many side effects including a proximal tubulopathy. Studies suggest that aminoaciduria is seen most commonly of all the biochemical abnormalities of ifosfamide-induced tubulopathy. A recent systematic review has found a paucity of data regarding the value of early markers indicating clinically significant tubulopathy. We undertook a pilot study to determine the feasibility of examining whether patients can be risk-stratified on the basis of aminoaciduria for the development of future significant ifosfamide-induced tubulopathy, to allow the evolution of appropriate follow-up strategies. We also aimed to define accrual rates, costs and clinical demands for a future larger study.

METHODS

This observational study recruited 21 patients from the Leeds Paediatric Oncology service. The medical notes of each patient were reviewed for demographic and clinical data. Simultaneous samples of blood and urine were obtained.

RESULTS

The investigations in the feasibility study were acceptable to patients and were minimally demanding on both clinical and laboratory staff. Financially, the cost per patient was minimal. This study was not powered to detect significant associations with TmP/GFR (ratio of renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate), growth and electrolyte supplementation. However, all patients with minimal aminoaciduria (≤2 elevated urinary amino acids) had normal TmP/GFR and no need for electrolyte supplementation.

CONCLUSIONS

This pilot study has shown that a larger study is feasible and may provide clinically useful data to change current practice. This should aim to establish whether the number of abnormal amino acids or the degree of abnormality is most significant in predicting clinically significant proximal tubulopathy.

[Renal late effects in patients treated for cancer in childhood]

Impaired renal function may occur following multimodal treatment of cancer in childhood. Renal late effects caused by chemotherapy, renal surgery and/or radiotherapy are now well described; but little is known about their prevalence and time of development. Herein, we provide a synthesis of the different renal complications that may occur with their physiopathology in relation with specific treatment exposures. This review summarized the literature that supported the recommendations issued by the long-term follow-up group of the "Société française des cancers de l'enfant (SFCE)" for childhood cancer survivors at risk for nephrotoxicity (www.sfce.org ; www.soc-nephrologie.org/SNP/index.htm). We developed these monitoring elements and the lifestyle recommendations for all asymptomatic survivors.

Phosphate homeostasis and disorders

Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

Interleukin 18 as a marker of chronic nephropathy in children after anticancer treatment

Novel markers of nephrotoxicity, including kidney injury molecule 1 (KIM-1), interleukin 18 (IL-18), and beta-2 microglobulin, were used in the detection of acute renal injury. The aim of the study was to establish the frequency of postchemotherapy chronic kidney dysfunction in children and to assess the efficacy of IL-18, KIM-1, and beta-2 microglobulin in the detection of chronic nephropathy. We examined eighty-five patients after chemotherapy (median age of twelve years). The median age at the point of diagnosis was 4.2 years, and the median follow-up time was 4.6 years. We performed classic laboratory tests assessing kidney function and compared the results with novel markers (KIM-1, beta-2 microglobulin, and IL-18). Features of subclinical renal injury were identified in forty-eight children (56.3% of the examined group). Nephropathy, especially tubulopathy, appeared more frequently in patients treated with ifosfamide, cisplatin, and/or carboplatin, following nephrectomy or abdominal radiotherapy (P = 0.14, P = 0.11, and P = 0.08, resp.). Concentrations of IL-18 and beta-2 microglobulin were comparable with classic signs of tubulopathy (P = 0.0001 and P = 0.05). Concentrations of IL-18 were also significantly higher in children treated with highly nephrotoxic drugs (P = 0.0004) following nephrectomy (P = 0.0007) and abdominal radiotherapy (P = 0.01). Concentrations of beta-2 microglobulin were higher after highly toxic chemotherapy (P = 0.004) and after radiotherapy (P = 0.02). ROC curves created utilizing IL-18 data allowed us to distinguish between children with nephropathy (value 28.8 pg/mL) and tubulopathy (37.1 pg/mL). Beta-2 microglobulin and IL-18 seem to be promising markers of chronic renal injury in children after chemotherapy.

Early and late renal adverse effects after potentially nephrotoxic treatment for childhood cancer

BACKGROUND

Great improvements in diagnostics and treatment for malignant disease in childhood have led to a major increase in survival. However, childhood cancer survivors (CCS) are at great risk for developing adverse effects caused by multimodal treatment for their malignancy. Nephrotoxicity is one of these known (acute) side effects of several treatments, including cisplatin, carboplatin, ifosfamide, radiotherapy and nephrectomy, and can cause glomerular filtration rate impairment, proteinuria, tubulopathy and hypertension. However, evidence about the long-term effects of these treatments on renal function remains inconclusive. To reduce the number of (long-term) nephrotoxic events in CCS, it is important to know the risk of, and risk factors for, early and late renal adverse effects, so that ultimately treatment and screening protocols can be adjusted.

OBJECTIVES

To evaluate existing evidence on the effects of potentially nephrotoxic treatment modalities on the prevalence of and associated risk factors for renal dysfunction in survivors treated for childhood cancer with a median or mean survival of at least one year after cessation of treatment, where possible in comparison with healthy controls or CCS treated without potentially nephrotoxic treatment.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 4, 2011), MEDLINE/PubMed (from 1945 to December 2011) and EMBASE/Ovid (from 1980 to December 2011).

SELECTION CRITERIA

With the exception of case reports, case series and studies including fewer than 20 participants, we included studies with all study designs that reported on renal function (one year or longer after cessation of treatment) in children and adults who were treated for a paediatric malignancy (aged 18 years or younger at diagnosis) with cisplatin, carboplatin, ifosfamide, radiation including the kidney region and/or a nephrectomy.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction using standardised data collection forms. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

The search strategy identified 5504 studies, of which 5138 were excluded on the basis of title and/or abstract. The full-text screening of the remaining 366 articles resulted in the inclusion of 57 studies investigating the prevalence of and sometimes also risk factors for early and late renal adverse effects of treatment for childhood cancer. The 57 studies included at least 13,338 participants of interest for this study, of whom at least 6516 underwent renal function testing. The prevalence of renal adverse effects ranged from 0% to 84%. This variation may be due to diversity in included malignancies, prescribed treatments, reported outcome measurements and the methodological quality of available evidence.Chronic kidney disease/renal insufficiency (as defined by the authors of the original studies) was reported in 10 of 57 studies. The prevalence of chronic kidney disease ranged between 0.5% and 70.4% in the 10 studies and between 0.5% and 18.8% in the six studies that specifically investigated Wilms' tumour survivors treated with a unilateral nephrectomy.A decreased (estimated) glomerular filtration rate was present in 0% to 50% of all assessed survivors (32/57 studies). Total body irradiation; concomitant treatment with aminoglycosides, vancomycin, amphotericin B or cyclosporin A; older age at treatment and longer interval from therapy to follow-up were significant risk factors reported in multivariate analyses. Proteinuria was present in 0% to 84% of all survivors (17/57 studies). No study performed multivariate analysis to assess risk factors for proteinuria.Hypophosphataemia was assessed in seven studies. Reported prevalences ranged between 0% and 47.6%, but four of seven studies found a prevalence of 0%. No studies assessed risk factors for hypophosphataemia using multivariate analysis. The prevalence of impairment of tubular phosphate reabsorption was mostly higher (range 0% to 62.5%; 11/57 studies). Higher cumulative ifosfamide dose, concomitant cisplatin treatment, nephrectomy and longer follow-up duration were significant risk factors for impaired tubular phosphate reabsorption in multivariate analyses.Treatment with cisplatin and carboplatin was associated with a significantly lower serum magnesium level in multivariate analysis, and the prevalence of hypomagnesaemia ranged between 0% and 37.5% in the eight studies investigating serum magnesium.Hypertension was investigated in 24 of the 57 studies. Reported prevalences ranged from 0% to 18.2%. A higher body mass index was the only significant risk factor noted in more than one multivariate analysis. Other reported factors that significantly increased the risk of hypertension were use of total body irradiation, abdominal irradiation, acute kidney injury, unrelated or autologous stem cell donor type, growth hormone therapy and older age at screening. Previous infection with hepatitis C significantly decreased the risk of hypertension.Because of the profound heterogeneity of the studies, it was not possible to perform any meta-analysis.

AUTHORS' CONCLUSIONS

The prevalence of renal adverse events after treatment with cisplatin, carboplatin, ifosfamide, radiation therapy involving the kidney region and/or nephrectomy ranged from 0% to 84%. With currently available evidence, it was not possible to draw any conclusions with regard to prevalence of and risk factors for renal adverse effects. Future studies should focus on adequate study design and reporting and should deploy multivariate risk factor analysis to correct for possible confounding. Until more evidence becomes available, CCS should be enrolled into long-term follow-up programmes to monitor their renal function and blood pressure.

Glucose conjugation for the specific targeting and treatment of cancer

Cancers of diverse origins exhibit marked glucose avidity and high rates of aerobic glycolysis. Increased understanding of this dysfunctional metabolism known as the Warburg effect has led to an interest in targeting it for cancer therapy. One promising strategy for such targeting is glycoconjugation, the linking of a drug to glucose or another sugar. This review summarizes the most salient examples of glycoconjugates, in which known cytotoxins or targeted anticancer therapeutics have been linked to glucose (or another glucose transporter substrate sugar) for improved cancer targeting and selectivity. Building on these examples, this review also provides a series of guidelines for the design and mechanistic evaluation of future glycoconjugates.

Medication-induced hypophosphatemia: a review

Hypophosphatemia (serum phosphorus concentration <2.5 mg/dl, 0.8 mmol/l), although rare in the general population, is commonly observed in hospitalized patients and may be associated with drug therapy. In fact, hypophosphatemia frequently develops in the course of treatment with drugs used in every-day clinical practice including diuretics and bisphosphonates. Proper diagnostic approach of patients with low serum phosphorus concentrations should involve a detailed medical history with special attention to the recent use of medications. The clinical manifestations of drug-induced hypophosphatemia are usually mild but might also be severe and potentially life-threatening. This review aims at a thorough understanding of the underlying pathophysiological mechanisms and risk factors of drug therapy-related hypophosphatemia thus allowing prevention and effective intervention strategies.

Long-term evaluation of Ifosfamide-related nephrotoxicity in children

PURPOSE

Ifosfamide is widely used in pediatric oncology but its nephrotoxicity may become a significant issue in survivors. This study is aimed at evaluating the incidence of late renal toxicity of ifosfamide and its risk factors.

PATIENTS AND METHODS

Of the 183 patients prospectively investigated for renal function, 77 treated for rhabdomyosarcoma, 39 for other soft tissue sarcoma, 39 for Ewing's sarcoma, and 28 for osteosarcoma were investigated at least 5 years after treatment. No patients had received cisplatin and/or carboplatin. Glomerular and tubular functions were graded according to the Skinner system.

RESULTS

The median dose of ifosfamide was 54 g/m(2) (range, 18 to 117 g/m(2)). After a median follow-up of 10 years, 89.5% of patients had normal tubular function, and 78.5% had normal glomerular function rate (GFR). Serum bicarbonate and calcium were normal in all patients. Hypomagnesemia was observed in 1.2% and hypophosphatemia in 1%. The tubular threshold for phosphate was reduced in 24% of the patients (grade 1 in 15%, grade 2 in 8%, and grade 3 in 0.5%). Glycosuria was detected in 37% of the patients but was more than 0.5 g/24 hours in only 5%. Proteinuria was observed in 12%. Ifosfamide dose and interval from therapy to investigations were predictors of tubulopathy in univariate and multivariate analysis. In a multivariate analysis, an older age at diagnosis and the length of interval since treatment had independent impacts on the risk of abnormal GFR.

CONCLUSION

Renal toxicity is moderate with a moderate dose of ifosfamide. However, since it can be permanent and can get worse with time, repeated long-term evaluations are important, and this risk should be balanced against efficacy.

Genitourinary long-term outcomes for childhood cancer survivors

The treatment of pediatric malignancies represents one of the success stories of modern medicine. As survival has increased, the focus is now on minimizing harmful effects of treatment. There continue to be late toxicities and secondary malignancies of the genitourinary (GU) system for childhood cancer survivors related to the specific therapeutic exposures. A systematic approach is important for prevention and treatment of these adverse late GU effects.

New ifosfamide analogs designed for lower associated neurotoxicity and nephrotoxicity with modified alkylating kinetics leading to enhanced in vitro anticancer activity

Ifosfamide is a well known prodrug for cancer treatment with cytochrome P450 metabolism. It is associated with both antitumor activity and toxicities. Isophosphoramide mustard is the bisalkylating active metabolite, and acrolein is a urotoxic side product. Because acrolein toxicity is limited by coadministration of sodium mercaptoethanesulfonate, the incidence of urotoxicity has been lowered. Current evidence suggests that chloroacetaldehyde, a side-chain oxidation metabolite, is responsible for neurotoxicity and nephrotoxicity. The aim of our research is to prevent chloroacetaldehyde formation using new enantioselectively synthesized ifosfamide analogs, i.e., C7,C9-dimethyl-ifosfamide. We hypothesize that reduced toxicogenic catabolism may induce less toxicity without changing anticancer activity. Metabolite determinations of the dimethyl-ifosfamide analogs were performed using liquid chromatography and tandem mass spectrometry after in vitro biotransformation by drug-induced rat liver microsomes and human microsomes expressing the main CYP3A4 and minor CYP2B6 enzymes. Both human and rat microsomes incubations produced the same N-deschloroalkylated and 4-hydroxylated metabolites. A coculture assay of 9L rat glioblastoma cells and rat microsomes was performed to evaluate their cytotoxicity. Finally, a mechanistic study using (31)P NMR kinetics allowed estimating the alkylating activity of the modified mustards. The results showed that C7,C9-dimethyl-ifosfamide exhibited increased activities, although they were still metabolized through the same N-deschloroalkylation pathway. Analogs were 4 to 6 times more cytotoxic than ifosfamide on 9L cells, and the generated dimethylated mustards were 28 times faster alkylating agents than ifosfamide mustards. Among these new ifosfamide analogs, the 7S,9R-enantiomer will be assessed for further in vivo investigations for its anticancer activity and its toxicological profile.

A systematic review of the accuracy and utility of early markers of Ifosfamide-induced proximal tubulopathy in survivors of childhood cancers

This study was conducted to identify and assess the accuracy and utility of any early markers of clinically significant proximal tubulopathy in children treated with ifosfamide chemotherapy. Ifosfamide is widely used either as a solitary agent or in conjunction with various other chemotherapeutic agents in treating solid tumors of childhood. It is highly effective but can cause short-term and long-term damage to kidneys, most commonly resulting in a tubular nephropathy and/or glomerular dysfunction. This may lead to chronic renal failure and metabolic bone disease in long-term survivors of childhood cancer. Multiple electronic databases (Cochrane, MEDLINE, EMBASE) were searched for primary studies describing the predictive value of early blood or urine tests to predict proximal tubulopathy. Citation searching (using reference lists and Science Citation Index searches) was also undertaken. Analysis was undertaken using criteria suggested by the MOOSE (Meta-analysis of Observational Studies in Epidemiology) collaboration. Studies were reviewed by at least 2 authors and disagreements resolved by consensus. Initial searches revealed approximately 310 studies of which 38 papers were selected for full analysis. Only 4 papers described the predictive value of early markers proximal tubular nephropathy. The remaining studies estimated prevalence of acute or chronic nephropathy without presenting predictive data. Of the 4 papers selected for analysis, 2 papers assessed the value of beta-2 microglobulinuria, and 3 addressed quantitative aminoaciduria. Test characteristics ranged from sensitivities of 82 to 100% and specificities of 84 to 100%, although the confidence intervals around these estimates were wide. Given the paucity of data, to consider further the use of early markers of proximal tubular nephropathy a prospective evaluation of patients who have been treated with ifosfamide based regimes should be undertaken.

Population pharmacokinetics and exploratory pharmacodynamics of ifosfamide according to continuous or short infusion schedules: an n = 1 randomized study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

* The optimal infusion duration for ifosfamide remains to be determined. * No differences according to time of infusion have been identified in traditional pharmacokinetic endpoints, such as area under the curve. * The impact on pharmacodynamics has never been modelled or correlated with pharmacokinetics.

WHAT THIS STUDY ADDS

* The pharmacokinetics and pharmacodynamics of ifosfamide and its main metabolites can both be modelled with no influence of infusion duration. * Pharmacodynamic modelling (renal and haematological toxicity) allows further simulations of new schedules with favourable toxicity profiles.

AIMS

To model the pharmacokinetics and pharmacodynamics of ifosfamide and its key metabolites. The pharmacodynamic parameters included were renal toxicity and myelosuppression measured using urinary beta(2)-microglobulin (BMG) and absolute neutrophil count (ANC), respectively.

METHODS

Seventeen patients were enrolled into an n = 1 randomized trial during two consecutive cycles of ifosfamide 9 g m(-2) during each cycle given by a 3 h or 72 h infusion. Data were analyzed using NONMEM.

RESULTS

Ifosfamide and metabolite concentration-time profiles were described by a one-compartment open-model with auto-induction of clearance. BMG and ANC time-courses were related to ifosfamide concentration via indirect response models.

CONCLUSIONS

This modelling allowed the simulation of weekly schedules of flat doses with favourable myelotoxic profiles.

Growth impairment after ifosfamide-induced nephrotoxicity in children

BACKGROUND

The goal of this study was to analyze long-term consequences of ifosfamide-induced nephrotoxicity on growth and renal function in children treated for cancer.

PROCEDURE

In a retrospective study, departments for pediatric oncology and nephrology in Germany, Austria, and Switzerland were asked to report patients with serious long-term nephrotoxicity after ifosfamide-treatment. Data at first appearance of renal dysfunction and at the last renal examination were collected using a standardized questionnaire.

RESULTS

Fifty-nine patients with tubulopathy (35 severe, 24 moderate) following ifosfamide therapy were eligible for analysis of long-term outcome (median follow-up 4 years, range 1.1 to 12.9). Median height standard deviation score was significantly reduced at renal diagnosis, and at last renal examination (-1.7 and -2.1 respectively, P < 0.01 at each point in time). Patients with tubulopathy also had stunted growth in comparison with a control group of cancer patients without renal disease (mean difference at last examination: 7.3 cm (95% confidence interval: 2.5 to 12.1 cm). In patients with severe tubulopathy, glomerular filtration rate deteriorated significantly over time. End-stage renal disease was reported in one patient only, not solely caused by ifosfamide.

CONCLUSION

Depending on the extent of tubular dysfunction, patients with ifosfamide-induced nephrotoxicity experienced significant growth impairment and a slow decline in glomerular filtration rate.

Ifosfamide-induced nephrotoxicity in 593 sarcoma patients: a report from the Late Effects Surveillance System

BACKGROUND

Ifosfamide is widely used in paediatric oncology, but its use is limited by nephrotoxic side effects. The aim of this study was to evaluate the incidence and risk factors of tubulopathy, with special emphasis on the influence of age, where different findings have been published so far.

PROCEDURE

Five hundred ninety three children and adolescents treated for Ewing, osteo- or soft-tissue sarcoma (median age at diagnosis: 11.7 years) were prospectively investigated for nephrotoxicity in the Late Effects Surveillance System (LESS) study. Tubulopathy was diagnosed in case of continuing hypophosphatemia and proteinuria.

RESULTS

After a median follow up of 19 months, 27 patients (4.6%; 95% CI: 3.0-6.6%) had newly developed tubulopathy. This incidence was 0.4% (95% CI: 0-2.4%) in patients treated with a cumulative ifosfamide dose of < or =24 g/m2, 6.5% (95% CI: 3.6-10.7%) after 24-60 g/m2, and 8.0% (95% CI: 4.2-13.6%) after > or = 60 g/m2. In multivariate analysis, children younger than 4 years at time of diagnosis had an 8.7-fold (95% CI: 3.5-21.8) higher risk for tubulopathy than older patients. Neither carboplatin treatment nor abdominal irradiation showed any significant influence.

CONCLUSION

Ifosfamide-induced nephrotoxicity was found in 4.6% of patients. Risk factors were the cumulative ifosfamide dose and young age at treatment.

Current chemotherapeutic strategies for rhabdomyosarcoma

Rhabdomyosarcoma is a typical tumor of childhood and adolescence. Over the years there has been a gradual but important improvement in survival for patients with this tumor, despite its high grade of malignancy. These results are due to multidisciplinary treatment approaches including surgery, radiotherapy and especially chemotherapy. Rhabdomyosarcoma is a highly chemosensitive neoplasm, and the role of this therapeutic approach has also been clearly demonstrated in the adjuvant setting. This review covers current concepts on chemotherapy for rhabdomyosarcoma, with an overview of the results of the main clinical trials conducted over recent years and considerations of possible strategies for the near future. Recommendations for adult patients with rhabdomyosarcoma are also discussed, suggesting that these patients should be treated according to pediatric guidelines.

Role of GSTM1, GSTP1, and GSTT1 gene polymorphism in ifosfamide metabolism affecting neurotoxicity and nephrotoxicity in children

The aim of this study was to evaluate the impact of GSTM1, GSTT1, and GSTP1 gene polymorphism on urinary excretion of unchanged ifosfamide, 2-dechloroethylifosfamide (2DCIF), and 3-dechloroethylifosfamide (3DCIF) with regard to the incidence of ifosfamide-related nephrotoxicity and neurotoxicity in children. The study comprised 76 children (38 girls, 38 boys) ages 9.84 to 210 months who were being treated for various malignant diseases with ifosfamide. The children were enrolled after identification of genotype coding for three classes of glutathione S-transferases (GSTM1, GSTT1, and GSTP1) at the initial stage of diagnosis. (P) nuclear magnetic resonance spectroscopy was used to analyze the urinary excretion of unchanged ifosfamide, 2DCIF, and 3DCIF metabolites on consecutive days after the end of the 3-hour infusion of ifosfamide. In children with polymorphic locus of the GSTP1 gene compared with children with homozygous wild alleles, increased urinary excretion of 3DCIF (P=0.029) and decreased creatinine clearance was found (Mann-Whitney P=0.03; median 81.1 mL/min/1.73 m vs. 105.0 mL/min/1.73 m, respectively). The authors' multidimensional analysis model revealed that besides the total ifosfamide dose and co-administration of other toxic drugs, polymorphic locus of GSTP1 gene may be one of the factors determining a higher toxicity of the cytostatic agent. The model was construed at P=0.029. Moreover, no correlation was found between the GSTM1 or GSTT1 genotype and ifosfamide toxicity and the urinary excretion of its metabolites. The results of this analysis indicate that individual reactions to ifosfamide can depend on inherited genetic polymorphisms, especially associated with the GSTP1 gene coding detoxifying enzyme.

Side Effects of Ifosfamide

Ifosfamide is relatively well tolerated but it can be associated occasionally with life-threatening complications such as arrhythmias and heart failure, severe encephalopathy and hemorrhagic cystitis. Mesna administration can control the urothelial toxicity of ifosfamide, but it is without effect on the other complications. Other preventive measures, such as amifostine or methylene blue administration, have not yet been adequately evaluated in a sufficient number of patients. Clinicians prescribing ifosfamide, especially in high doses, should be watchful for early signs of toxicity in order to discontinue ifosfamide administration soon enough to avoid development of major toxicity.