Glomerular function time trends in long-term survivors of childhood cancer: a longitudinal study

Pathological Insights into Non-Neoplastic Renal Parenchyma in Wilms Tumor: Implications for Nephron-Sparing Surgery

INTRODUCTION

 This study aimed to evaluate the non-neoplastic renal parenchyma in Wilms tumor (WT) and investigate its impact on nephron-sparing surgery (NSS).

MATERIALS AND METHODS

 The non-neoplastic renal parenchyma of WT patients was prospectively collected for pathological examination. The histology of non-neoplastic renal parenchyma was assessed from two perspectives: nephrogenic rests (NRs) and nephrons.

RESULTS

 A total of 46 non-neoplastic renal parenchyma specimens were collected from 42 WT patients. The surgeons assessed the median proportion of non-neoplastic renal parenchyma as 30%, whereas using ellipsoid volume, it was calculated to be 27%. The Youden index of surgeons' assessment peaked at a 15% proportion of non-neoplastic renal parenchyma. The bilateral WT (BWT) group and NSS group exhibited significant differences compared with the unilateral WT group and radical nephrectomy group, respectively, with the BWT group showing a tendency toward thickened basement membrane.

CONCLUSION

 The presence of NRs and endogenous nephron alternations should be given due attention in WT. The probability of abnormalities is low when the proportion of non-neoplastic renal parenchyma exceeds 15%, providing pathological support for expanding the adaptation of NSS.

Nephrotoxicity Surveillance for Childhood and Young Adult Survivors of Cancer: Recommendations From the International Late Effects of Childhood Cancer Guideline Harmonization Group

PURPOSE

Childhood, adolescent, and young adult (CAYA) survivors of cancer are at risk of nephrotoxicity. Surveillance guidelines are important for timely diagnosis and treatment of these survivors, which could slow the progression to higher stages of kidney dysfunction.

METHODS

The International Late Effects of Childhood Cancer Guideline Harmonization Group established a multidisciplinary panel of 34 experts from 11 countries. The panel performed systematic literature reviews for articles published between 1990 and June 2023, graded the evidence using Grading of Recommendations Assessment, Development, and Evaluation methodology, and formulated recommendations based on evidence, clinical judgment, and consideration of benefits and harms of surveillance. Recommendations were critically appraised by two independent external experts and patient representatives.

RESULTS

Glomerular dysfunction surveillance is recommended every 2-5 years for survivors treated with ifosfamide, cisplatin, abdominal radiotherapy, total body irradiation, or nephrectomy and is reasonable after carboplatin treatment. We recommend screening for glomerular dysfunction using an estimated glomerular filtration rate (eGFR) equation that includes serum creatinine, preferably combined with serum cystatin C if available. Tubular dysfunction surveillance is recommended once at entry into long-term follow-up and with follow-up as clinically indicated for survivors treated with ifosfamide and is reasonable after cisplatin treatment.

CONCLUSION

These recommendations inform routine, uniform long-term follow-up care for CAYA survivors of cancer at risk of nephrotoxicity.

Chronic Kidney Disease or Hypertension After Childhood Cancer

Importance

Post-cancer therapy kidney outcomes, including chronic kidney disease (CKD) and hypertension, are common in childhood cancer survivors (CCS). The incidence and timing of CKD and hypertension in CCS compared with other at-risk or general populations are unclear.

Objective

To determine the association of childhood cancer treatment with post-cancer therapy CKD or hypertension.

Design, Setting, and Participants

Population-based matched cohort study of children treated for cancer between April 1993 and March 2020 in Ontario, Canada, with follow-up until March 2021. The CCS (exposed) cohort included children (≤18 years) surviving cancer. Comparator cohorts were a hospitalization cohort (children who were hospitalized) and a general pediatric population (GP) cohort (all other Ontario children). Exclusion criteria were history of previous cancer, organ transplant, CKD, dialysis, or hypertension. Matching with each of the 2 comparator cohorts was performed separately and in a 1:4 ratio by age, sex, rural vs urban status, income quintile, index year, and presence of previous hospitalization. Data were analyzed from March 2021 to August 2024.

Exposure

Treatment for cancer.

Main Outcomes and Measures

The primary outcome was the composite of CKD or hypertension, defined by administrative health care diagnosis and procedure codes. Fine and Gray subdistribution hazard modeling, accounting for competing risks (death and new cancer diagnosis or relapse) and adjusting for cardiac disease, liver disease, and diabetes, was used to determine the association of cancer treatment with outcomes.

Results

There were 10 182 CCS (median [IQR] age at diagnosis, 7 [3-13] years; 5529 male [54.3%]; median [IQR] follow-up time, 8 [2-15] years) matched to 40 728 hospitalization cohort patients (median [IQR] age at diagnosis, 7 [2-12] years; 5529 male [weighted percentage, 54.3%]; median [IQR] follow-up time, 11 [6-18] years) and 8849 CCS (median [IQR] age at diagnosis, 5 [2-11] years; 4825 male [54.5%]; median [IQR] follow-up time, 7 [2-14] years) matched to 35 307 GP cohort individuals (median [IQR] age at diagnosis, 6 [2-11] years; 4825 male [weighted percentage, 54.5%]; median [IQR] follow-up time, 10 [5-16] years). Most frequent cancer types were leukemia (2948 patients [29.0%]), central nervous system neoplasms (2123 patients [20.9%]), and lymphoma (1583 patients [15.5%]). During observation, cumulative incidence of CKD or hypertension was 20.85% (95% CI, 18.75%-23.02%) in the CCS cohort vs 16.47% (95% CI, 15.21%-17.77%) in the hospitalization cohort and 19.24% (95% CI, 15.99%-22.73%) in the CCS cohort vs 8.05% (95% CI, 6.76%-9.49%) in the GP cohort. CCS were at increased risk of CKD or hypertension compared with the hospitalization cohort (adjusted hazard ratio, 2.00; 95% CI, 1.86-2.14; P < .001) and the GP cohort (adjusted hazard ratio, 4.71; 95% CI, 4.27-5.19; P < .001).

Conclusions and Relevance

In this population-based study, CCS were at increased risk for CKD and hypertension, which are associated with mortality, suggesting that early detection and treatment of these conditions in CCS may decrease late complications and mortality.

Kidney Disease in Childhood Cancer Survivors Treated With Radiation Therapy: A PENTEC Comprehensive Review

PURPOSE

Kidney injury is a known late and potentially devastating complication of abdominal radiation therapy (RT) in pediatric patients. A comprehensive Pediatric Normal Tissue Effects in the Clinic review by the Genitourinary (GU) Task Force aimed to describe RT dose-volume relationships for GU dysfunction, including kidney, bladder, and hypertension, for pediatric malignancies. The effect of chemotherapy was also considered.

METHODS AND MATERIALS

We conducted a comprehensive PubMed search of peer-reviewed manuscripts published from 1990 to 2017 for investigations on RT-associated GU toxicities in children treated for cancer. We retrieved 3271 articles with 100 fulfilling criteria for full review, 24 with RT dose data and 13 adequate for modeling. Endpoints were heterogenous and grouped according to National Kidney Foundation: grade ≥1, grade ≥2, and grade ≥3. We modeled whole kidney exposure from total body irradiation (TBI) for hematopoietic stem cell transplant and whole abdominal irradiation (WAI) for patients with Wilms tumor. Partial kidney tolerance was modeled from a single publication from 2021 after the comprehensive review revealed no usable partial kidney data. Inadequate data existed for analysis of bladder RT-associated toxicities.

RESULTS

The 13 reports with long-term GU outcomes suitable for modeling included 4 on WAI for Wilms tumor, 8 on TBI, and 1 for partial renal RT exposure. These reports evaluated a total of 1191 pediatric patients, including: WAI 86, TBI 666, and 439 partial kidney. The age range at the time of RT was 1 month to 18 years with medians of 2 to 11 years in the various reports. In our whole kidney analysis we were unable to include chemotherapy because of the heterogeneity of regimens and paucity of data. Age-specific toxicity data were also unavailable. Wilms studies occurred from 1968 to 2011 with mean follow-ups 8 to 15 years. TBI studies occurred from 1969 to 2004 with mean follow-ups of 4 months to 16 years. We modeled risk of dysfunction by RT dose and grade of toxicity. Normal tissue complication rates ≥5%, expressed as equivalent doses, 2 Gy/fx for whole kidney exposures occurred at 8.5, 10.2, and 14.5 Gy for National Kidney Foundation grades ≥1, ≥2, and ≥3, respectively. Conventional Wilms WAI of 10.5 Gy in 6 fx had risks of ≥grade 2 toxicity 4% and ≥grade 3 toxicity 1%. For fractionated 12 Gy TBI, those risks were 8% and <3%, respectively. Data did not support whole kidney modeling with chemotherapy. Partial kidney modeling from 439 survivors who received RT (median age, 7.3 years) demonstrated 5 or 10 Gy to 100% kidney gave a <5% risk of grades 3 to 5 toxicity with 1500 mg/m2 carboplatin or no chemo. With 480 mg/m2 cisplatin, a 3% risk of ≥grade 3 toxicity occurred without RT and a 5% risk when 26% kidney received ≥10 Gy. With 63 g/m2 of ifosfamide, a 5% risk of ≥grade 3 toxicity occurred with no RT, and a 10% toxicity risk occurred when 42% kidney received ≥10 Gy.

CONCLUSIONS

In patients with Wilms tumor, the risk of toxicity from 10.5 Gy of WAI is low. For 12 Gy fractionated TBI with various mixtures of chemotherapy, the risk of severe toxicity is low, but low-grade toxicity is not uncommon. Partial kidney data are limited and toxicity is associated heavily with the use of nephrotoxic chemotherapeutic agents. Our efforts demonstrate the need for improved data gathering, systematic follow-up, and reporting in future clinical studies. Current radiation dose used for Wilms tumor and TBI appear to be safe; however, efforts in effective kidney-sparing TBI and WAI regimens may reduce the risks of renal injury without compromising cure.

Circulating Levels of Soluble α-Klotho and FGF23 in Childhood Cancer Survivors: Lack of Association with Nephro- and Cardiotoxicity-A Preliminary Study

Background/Objectives: The survival rate among pediatric cancer patients has reached 80%; however, these childhood cancer survivors (CCSs) are at a heightened risk of developing chronic conditions in adulthood, particularly kidney and cardiovascular diseases. The aims of this study were to assess the serum α-Klotho and FGF23 levels in CCSs and to determine their association with nephro- and cardiotoxicity. Methods: This study evaluated a cohort of 66 CCSs who remained in continuous remission, with a mean follow-up of 8.41 ± 3.76 years. Results: The results of this study revealed that CCSs exhibited significantly higher levels of soluble α-Klotho compared to healthy peers (1331.4 ± 735.5 pg/mL vs. 566.43 ± 157.7 pg/mL, p < 0.0001), while no significant difference was observed in their FGF23 levels. Within the participant cohort, eight individuals (12%) demonstrated a reduced estimated glomerular filtration rate (eGFR) below 90 mL/min/1.73 m2. The relationship between treatment with abdominal radiotherapy and reduced eGFR was confirmed (p < 0.05). No correlations were found between potential treatment-related risk factors, such as chemotherapy or radiation therapy, serum levels of α-Klotho and FGF23, and nephro- and cardiotoxicity. Conclusions: In conclusion, this preliminary cross-sectional study revealed elevated levels of α-Klotho among childhood cancer survivors but did not establish a direct association with anticancer treatment. The significance of elevated α-Klotho protein levels among CCSs warrants further investigation.

Long-term cisplatin nephrotoxicity after childhood cancer: a systematic review and meta-analysis

BACKGROUND

Cisplatin is a chemotherapeutic drug commonly used in the treatment of many childhood solid malignancies. It is known to cause long-term nephrotoxicity, most commonly manifesting as reduced glomerular filtration rate and hypomagnesaemia. Existing literature regarding the epidemiology of long-term nephrotoxicity in childhood cancer describes large variation in prevalence and risk factors.

OBJECTIVES

This study is to evaluate the prevalence of, and risk factors for, long-term cisplatin nephrotoxicity after treatment for childhood cancer.

STUDY ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they: (i) evaluated participants treated with cisplatin who were diagnosed with cancer < 18 years of age; (ii) investigated any author-defined measure of nephrotoxicity; and (iii) performed this evaluation 3 or more months after cisplatin cessation. Studies whose scope was broader than this were included if appropriate subgroup analysis was performed.

RESULTS

Prevalence of reduced glomerular filtration rate (GFR) ranged between 5.9 and 48.1%. Pooled prevalence of reduced GFR using studies with a modern consensus threshold of 90 ml/min/1.73 m2 was 29% (95% CI 0.0-58%). Prevalence of hypomagnesaemia ranged between 8.0 and 71.4%. Pooled prevalence of hypomagnesaemia was 37% (95% CI 22-51%). Substantial heterogeneity was present, with I2 statistics of 94% and 73% for reduced GFR and hypomagnesaemia respectively. All large, long-term follow-up studies described increased risk of reduced GFR with increasing cumulative cisplatin dose. Included studies varied as to whether cisplatin was a risk factor for proteinuria, and whether age was a risk factor for cisplatin nephrotoxicity.

LIMITATIONS

A wide range of study methodologies were noted which impeded analysis. No studies yielded data from developing health-care settings. No non-English studies were included, further limiting generalisability.

CONCLUSIONS

Both of the most common manifestations of long-term cisplatin nephrotoxicity have a prevalence of approximately a third, with increasing cumulative dose conferring increased risk of nephrotoxicity. Further work is needed to characterise the relationship between reduced GFR and hypomagnesaemia, investigate other risk factors and understand the interindividual variation in susceptibility to nephrotoxicity.

Chapter 4: CKD treatment in cancer survivors, from Clinical Practice Guidelines for the Management of Kidney Injury During Anticancer Drug Therapy 2022

Chronic kidney disease (CKD) is one of the most disabling disorders with significant comorbidity and mortality. Incidence and prevalence of CKD in cancer survivors are remarkably high in both adults and pediatric patients. The reasons for this high incidence/prevalence are multifold but kidney damage by cancer itself and cancer treatment (pharmacotherapy/surgery/radiation) are the main reasons. Since cancer survivors commonly have significant comorbidities, risk of cancer recurrence, limited physical function or life expectancy, special attentions should be paid when considering the treatment of CKD and its complications. Especially, shared decision-making should be considered when selecting the renal replacement therapies with as much information/facts/evidence as possible.

The Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis examined long-term glomerular dysfunction in childhood cancer survivors

This investigation aimed to evaluate glomerular dysfunction among childhood cancer survivors in comparison with matched controls from the general population. In the Dutch Childhood Cancer Survivor Study (DCCSS)-LATER 2 kidney analysis, a nationwide cross-sectional cohort study, 1024 survivors five or more years after diagnosis, aged 18 or more years at study, treated between 1963-2001 with nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide or hematopoietic stem cell transplantation participated. In addition, 500 age- and sex-matched controls from Lifelines, a prospective population-based cohort study in the Netherlands, participated. At a median age of 32.0 years (interquartile range 26.6-37.4), the glomerular filtration rate was under 60 ml/min/1.73m² in 3.7% of survivors and in none of the controls. Ten survivors had kidney failure. Chronic kidney disease according to age-thresholds (glomerular filtration rate respectively under 75 for age under 40, under 60 for ages 40-65, and under 40 for age over 65) was 6.6% in survivors vs. 0.2% in controls. Albuminuria (albumin-to-creatinine ratio over3 mg/mmol) was found in 16.2% of survivors and 1.2% of controls. Risk factors for chronic kidney disease, based on multivariable analyses, were nephrectomy (odds ratio 3.7 (95% Confidence interval 2.1-6.4)), abdominal radiotherapy (1.8 (1.1-2.9)), ifosfamide (2.9 (1.9-4.4)) and cisplatin over 500 mg/m² (7.2 (3.4-15.2)). For albuminuria, risk factors were total body irradiation (2.3 (1.2-4.4)), abdominal radiotherapy over 30 Gy (2.6 (1.4- 5.0)) and ifosfamide (1.6 (1.0-2.4)). Hypertension and follow-up 30 or more years increased the risk for glomerular dysfunction. Thus, lifetime monitoring of glomerular function in survivors exposed to these identified high risk factors is warranted.

KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors: Description of Clinical Research Protocol of the KINDEST-CCS Study

Background

Approximately 30% of childhood cancer survivors (CCSs) will develop chronic kidney disease (CKD) or hypertension 15 to 20 years after treatment ends. The incidence of CKD and hypertension in the 5-year window after cancer therapy is unknown. Moreover, extent of monitoring of CCS with CKD and associated complications in current practice is underexplored. To inform the development of new and existing care guidelines for CCS, the epidemiology and monitoring of CKD and hypertension in the early period following cancer therapy warrants further investigation.

Objective

To describe the design and methods of the KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors study, which aims to evaluate the burden of late kidney and blood pressure outcomes in the first ~10 years after cancer therapy, the extent of appropriate screening and complications monitoring for CKD and hypertension, and whether patient, disease/treatment, or system factors are associated with these outcomes.

Design

Two distinct, but related studies; a prospective cohort study and a retrospective cohort study.

Setting

Five Ontario pediatric oncology centers.

Patients

The prospective study will involve 500 CCS at high risk for these late effects due to cancer therapy, and the retrospective study involves 5,000 CCS ≤ 18 years old treated for cancer between January 2008 and December 2020.

Measurements

Chronic kidney disease is defined as Estimated glomerular filtration rate <90 mL/min/1.73 m² or albumin-to-creatinine ratio ≥ 3mg/mmol. Hypertension is defined by 2017 American Academy of Pediatrics guidelines.

Methods

Prospective study: we aim to investigate CKD and hypertension prevalence and the extent to which they persist at 3- and 5-year follow-up in CCS after cancer therapy. We will collect detailed biologic and clinical data, calculate CKD and hypertension prevalence, and progression at 3- and 5-years post-therapy. Retrospective study: we aim to investigate CKD and hypertension monitoring using administrative and health record data. We will also investigate the validity of CKD and hypertension administrative definitions in this population and the incidence of CKD and hypertension in the first ~10 years post-cancer therapy. We will investigate whether patient-, disease/treatment-, or system-specific factors modify these associations in both studies.

Limitations

Results from the prospective study may not be generalizable to non-high-risk CCS. The retrospective study is susceptible to surveillance bias.

Conclusions

Our team and knowledge translation plan is engaging patient partners, researchers, knowledge users, and policy group representatives. Our work will address international priorities to improve CCS health, provide the evidence of new disease burden and practice gaps to improve CCS guidelines, implement and test revised guidelines, plan trials to reduce CKD and hypertension, and improve long-term CCS health.

Acute kidney injury during cisplatin therapy and associations with kidney outcomes 2 to 6 months post-cisplatin in children: a multi-centre, prospective observational study

BACKGROUND

Few studies describe acute kidney injury (AKI) burden during paediatric cisplatin therapy and post-cisplatin kidney outcomes. We determined risk factors for and rate of (1) AKI during cisplatin therapy, (2) chronic kidney disease (CKD) and hypertension 2-6 months post-cisplatin, and (3) whether AKI is associated with 2-6-month outcomes.

METHODS

This prospective cohort study enrolled children (aged < 18 years at cancer diagnosis) treated with cisplatin from twelve Canadian hospitals. AKI during cisplatin therapy (primary exposure) was defined based on Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria (≥ stage one). Severe electrolyte abnormalities (secondary exposure) included ≥ grade three hypophosphatemia, hypokalemia, or hypomagnesemia (National Cancer Institute Common Terminology Criteria for Adverse Events v4.0). CKD was albuminuria or decreased kidney function for age (KDIGO guidelines). Hypertension was defined based on the 2017 American Academy of Pediatrics guidelines.

RESULTS

Of 159 children (median [interquartile range [IQR]] age: 6 [2-12] years), 73/159 (46%) participants developed AKI and 55/159 (35%) experienced severe electrolyte abnormalities during cisplatin therapy. At median [IQR] 90 [76-110] days post-cisplatin, 53/119 (45%) had CKD and 18/128 (14%) developed hypertension. In multivariable analyses, AKI was not associated with 2-6-month CKD or hypertension. Severe electrolyte abnormalities during cisplatin were associated with having 2-6-month CKD or hypertension (adjusted odds ratio (AdjOR) [95% CI]: 2.65 [1.04-6.74]). Having both AKI and severe electrolyte abnormalities was associated with 2-6-month hypertension (AdjOR [95% CI]: 3.64 [1.05-12.62]).

CONCLUSIONS

Severe electrolyte abnormalities were associated with kidney outcomes. Cisplatin dose optimization to reduce toxicity and clear post-cisplatin kidney follow-up guidelines are needed. A higher resolution version of the Graphical abstract is available as Supplementary information.

Prospective Evaluation of Kidney Function in Long-Term Survivors of Pediatric CNS Tumors

Purpose: Numerous acute effects of chemotherapeutics on kidney function are well described. However, data on the long-term effects of chemotherapy in the growing population of childhood central nervous system (CNS) tumor survivors is limited. We aimed to evaluate the kidney function of a cohort of long-term CNS tumor survivors treated with different standard chemotherapeutic regimens. Methods: Patients treated for a CNS tumor were prospectively evaluated up to 12 years after completion of their therapy. Examination of kidney function was performed during routine follow-up visits. Blood pressure and blood and urine parameters were analyzed for kidney function evaluation. Glomerular function was assessed by calculating the estimated glomerular filtration rate (eGFR), tubular functions were analyzed by measuring serum electrolytes, bicarbonate and phosphate reabsorption, and proteinuria was assessed by calculating the protein/creatinine ratio and phosphate reabsorption. Results: None of the 65 patients evaluated suffered from clinically relevant kidney impairment (eGFR < 90 mL/min/L, 73 m2). There was no association between chemotherapy dose and eGFR. Only two patients showed mild signs of tubulopathy and 11 patients were diagnosed with elevated blood pressure. Conclusion: With adequate supportive measures, such as sufficient hydration according to chemotherapy protocol guidelines, as well as avoidance or close monitoring of additional nephrotoxic medication, impaired kidney function is rare in CNS tumor survivors treated with standard chemotherapy. Nonetheless, long-term follow-up is essential for early detection of mild impairment of kidney function.

Kidney disease in very long-term survivors of Wilms tumor: A nationwide cohort study with sibling controls

BACKGROUND

Survival after Wilms tumor has significantly increased and focus on late effects has become increasingly important. However, knowledge about long-term renal function in survivors of Wilms tumor is missing. Our aim was to investigate evidence of kidney disease in 20- or more-year survivors of Wilms tumor in a clinical setting, with siblings as comparisons.

METHODS

In this cross-sectional study, we established a cohort of Danish 20-plus-year survivors of Wilms tumor and siblings as controls. Participants answered a comprehensive health questionnaire supplemented by measurements of estimated glomerular filtration rate (eGFR), urine albumin-to-creatinine ratio, and blood pressure and were categorized according to the chronic kidney disease classification. Multiple linear regression analysis, taking family membership into account, was used to describe the differences in eGFR. Logistic regression analysis was performed to describe risk factors for the development of kidney disease.

RESULTS

We included 99 survivors of Wilms tumor and 38 sibling controls with a median of 37 years of follow-up. The eGFR of Wilms tumor survivors was 13 ml/min/1.73 m² (95% CI -20; -5) lower when compared to sibling control. Evidence of kidney disease, with risk factors as hypertension and diabetes, was found in 19% of the Wilms tumor survivors and 2% developed end-stage renal disease. Ninety-two percent of the Wilms tumor survivors had an eGFR >60 ml/min/1.73² .

CONCLUSION

Long-term Wilms tumor survivors have on average a significantly decreased renal function along with the increased prevalence of kidney disease and end-stage renal disease when compared to sibling controls. Still, most survivors had kidney function within the normal range.

Long-Term Tubular Dysfunction in Childhood Cancer Survivors; DCCSS-LATER 2 Renal Study

The aim of this nationwide cross-sectional cohort study was to determine the prevalence of and risk factors for tubular dysfunction in childhood cancer survivors (CCS). In the DCCSS-LATER 2 Renal study, 1024 CCS (≥5 years after diagnosis), aged ≥ 18 years at study, treated between 1963 and 2001 with potentially nephrotoxic therapy (i.e., nephrectomy, abdominal radiotherapy, total body irradiation, cisplatin, carboplatin, ifosfamide, high-dose cyclophosphamide, or hematopoietic stem cell transplantation) participated, and 500 age- and sex-matched participants from Lifelines acted as controls. Tubular electrolyte loss was defined as low serum levels (magnesium < 0.7 mmol/L, phosphate < 0.7 mmol/L and potassium < 3.6 mmol/L) with increased renal excretion or supplementation. A α1-microglobulin:creatinine ratio > 1.7 mg/mmol was considered as low-molecular weight proteinuria (LMWP). Multivariable risk analyses were performed. After median 25.5 years follow-up, overall prevalence of electrolyte losses in CCS (magnesium 5.6%, potassium 4.5%, phosphate 5.5%) was not higher compared to controls. LMWP was more prevalent (CCS 20.1% versus controls 0.4%). LMWP and magnesium loss were associated with glomerular dysfunction. Ifosfamide was associated with potassium loss, phosphate loss (with cumulative dose > 42 g/m2) and LMWP. Cisplatin was associated with magnesium loss and a cumulative dose > 500 mg/m2 with potassium and phosphate loss. Carboplatin cumulative dose > 2800 mg/m2 was associated with potassium loss. In conclusion, long-term tubular dysfunction is infrequent. Yet, ifosfamide, cisplatin and carboplatin are risk factors.

Extracorporeal Treatment for Methotrexate Poisoning: Systematic Review and Recommendations from the EXTRIP Workgroup

Methotrexate is used in the treatment of many malignancies, rheumatological diseases, and inflammatory bowel disease. Toxicity from use is associated with severe morbidity and mortality. Rescue treatments include intravenous hydration, folinic acid, and, in some centers, glucarpidase. We conducted systematic reviews of the literature following published EXtracorporeal TReatments In Poisoning (EXTRIP) methods to determine the utility of extracorporeal treatments in the management of methotrexate toxicity. The quality of the evidence and the strength of recommendations (either "strong" or "weak/conditional") were graded according to the GRADE approach. A formal voting process using a modified Delphi method assessed the level of agreement between panelists on the final recommendations. A total of 92 articles met inclusion criteria. Toxicokinetic data were available on 90 patients (89 with impaired kidney function). Methotrexate was considered to be moderately dialyzable by intermittent hemodialysis. Data were available for clinical analysis on 109 patients (high-dose methotrexate [>0.5 g/m2]: 91 patients; low-dose [≤0.5 g/m2]: 18). Overall mortality in these publications was 19.5% and 26.7% in those with high-dose and low-dose methotrexate-related toxicity, respectively. Although one observational study reported lower mortality in patients treated with glucarpidase compared with those treated with hemodialysis, there were important limitations in the study. For patients with severe methotrexate toxicity receiving standard care, the EXTRIP workgroup: (1) suggested against extracorporeal treatments when glucarpidase is not administered; (2) recommended against extracorporeal treatments when glucarpidase is administered; and (3) recommended against extracorporeal treatments instead of administering glucarpidase. The quality of evidence for these recommendations was very low. Rationales for these recommendations included: (1) extracorporeal treatments mainly remove drugs in the intravascular compartment, whereas methotrexate rapidly distributes into cells; (2) extracorporeal treatments remove folinic acid; (3) in rare cases where fast removal of methotrexate is required, glucarpidase will outperform any extracorporeal treatment; and (4) extracorporeal treatments do not appear to reduce the incidence and magnitude of methotrexate toxicity.

Late effects of high-dose methotrexate treatment in childhood cancer survivors-a systematic review

BACKGROUND

High-dose methotrexate (HD-MTX) is used in the treatment of different childhood cancers, including leukemia, the most common cancer type and is commonly defined as an intravenous dose of at least 1 g/m² body surface area per application. A systematic review on late effects on different organs due to HD-MTX is lacking.

METHOD

We conducted a systematic literature search in PubMed, including studies published in English or German between 1985 and 2020. The population of each study had to consist of at least 75% childhood cancer survivors (CCSs) who had completed the cancer treatment at least twelve months before late effects were assessed and who had received HD-MTX. The literature search was not restricted to specific cancer diagnosis or organ systems at risk for late effects. We excluded case reports, case series, commentaries, editorial letters, poster abstracts, narrative reviews and studies only reporting prevalence of late effects. We followed PRISMA guidelines, assessed the quality of the eligible studies according to GRADE criteria and registered the protocol on PROSPERO (ID: CRD42020212262).

RESULTS

We included 15 out of 1731 identified studies. Most studies included CCSs diagnosed with acute lymphoblastic leukemia (n = 12). The included studies investigated late effects of HD-MTX on central nervous system (n = 10), renal (n = 2) and bone health (n = 3). Nine studies showed adverse outcomes in neuropsychological testing in exposed compared to non-exposed CCSs, healthy controls or reference values. No study revealed lower bone density or worse renal function in exposed CCSs. As a limitation, the overall quality of the studies per organ system was low to very low, mainly due to selection bias, missing adjustment for important confounders and low precision.

CONCLUSIONS

CCSs treated with HD-MTX might benefit from neuropsychological testing, to intervene early in case of abnormal results. Methodological shortcomings and heterogeneity of the tests used made it impossible to determine the most appropriate test. Based on the few studies on renal function and bone health, regular screening for dysfunction seems not to be justified. Only screening for neurocognitive late effects is warranted in CCSs treated with HD-MTX.

Dimethylarginines in Children after Anti-Neoplastic Treatment

Background and Objectives: According to a recent Cochrane systematic review, renal impairment can develop in 0-84% of childhood cancer survivors in the future. The renal function impairment in this patient group can be related to nephrectomy, nephrotoxic agents therapy, abdominal radiotherapy, and combinations of these treatment methods. In this study, in a population of patients after anti-neoplastic therapy, with particular emphasis on patients after Wilms' tumour treatment, we compared new substances which play role in the chronic kidney disease (CKD) pathogenesis (asymmetric dimethylarginine-ADMA, symmetric dimethylarginine-SDMA) with standard renal function markers (e.g., creatinine and cystatin C in serum, creatinine in urine, etc.) to assess the usefulness of the former. Materials and Methods: Eighty-four children, without CKD, bilateral kidney tumours, congenital kidney defects, or urinary tract infections, with a minimum time of 1 year after ending anti-neoplastic treatment, aged between 17 and 215 months, were divided into three groups: group 1-patients after nephroblastoma treatment (n = 21), group 2-after other solid tumours treatment (n = 44), and group 3-after lymphoproliferative neoplasms treatment (n = 19). The patients' medical histories were taken and physical examinations were performed. Concentrations of blood urea nitrogen (BUN), creatinine, cystatin C, C-reactive protein (CRP), ADMA, and SDMA in blood and albumin in urine were measured, and a general urine analysis was performed. The SDMA/ADMA ratio, albumin-creatine ratio, and estimated glomerular filtration rate (eGFR) were calculated. eGFR was estimated by three equations recommended to the paediatric population by the KDIGO from 2012: the Schwartz equation (eGFR1), equation with creatinine and urea nitrogen (eGFR2), and equation with cystatin C (eGFR3). Results: Both the eGFR1 and eGFR2 values were significantly lower in group 1 than in group 3 (eGFR1: 93.3 (83.1-102.3) vs. 116.5 (96.8-126.9) mL/min/1.73 m2, p = 0.02; eGFR2: 82.7 (±14.4) vs. 94.4 (±11.9) mL/min/1.73 m2, p = 0.02). Additionally, there were weak positive correlations between SDMA and creatinine (p < 0.05, r = 0.24), and cystatin C (p < 0.05, r = 0.32) and weak negative correlations between SDMA and eGFR1 (p < 0.05, r = -0.25), eGFR2 (p < 0.05, r = -0.24), and eGFR3 (p < 0.05, r = -0.32). Conclusions: The usefulness of ADMA and SDMA in the diagnosis of renal functional impairment should be assessed in further studies. eGFR, calculated according to equations recommended for children, should be used in routine paediatric practice.

Urinary Beta-2-Microglobulin and Late Nephrotoxicity in Childhood Cancer Survivors

The objectives of this study were to evaluate urinary beta-2-microglobulin (β2M) levels in long-term childhood cancer survivors and to establish its association with anticancer drug-induced nephrotoxicity. The study consisted of 165 childhood cancer survivors (CCS) who were in continuous complete remission. We reported that CCS had a significantly higher level of β2M (p < 0.001) and β2M/Cr. ratio (p < 0.05) than healthy peers. Among all participants, 24 (14.5%) had decreased eGFR (<90 mL/min/1.73 m²). A significant positive correlation between β2M/Cr. ratio and body mass index (coef. 14.48, p = 0.046) was found. Furthermore, higher levels of urinary β2M were detected among CCS with a longer follow-up time (over 5 years) after treatment. Subjects with decreased eGFR showed statistically higher urinary β2M levels (20.06 ± 21.56 ng/mL vs. 8.55 ± 3.65 ng/mL, p = 0.007) compared with the healthy peers. Twelve survivors (7.2%) presented hyperfiltration and they had higher urinary β2M levels than CCS with normal glomerular filtration (46.33 ± 93.11 vs. 8.55 ± 3.65 ng/mL, p = 0.029). This study did not reveal an association between potential treatment-related risk factors such as chemotherapy, surgery, radiotherapy, and the urinary β2M level. The relationship between treatment with abdominal radiotherapy and reduced eGFR was confirmed (p < 0.05). We demonstrated that urinary beta-2-microglobulin may play a role in the subtle kidney injury in childhood cancer survivors; however, the treatment-related factors affecting the β2M level remain unknown. Further prospective studies with a longer follow-up time are needed to confirm the utility of urinary β2M and its role as a non-invasive biomarker of renal dysfunction.

Long-term morbidity and mortality in 2-year hepatoblastoma survivors treated with SIOPEL risk-adapted strategies

BACKGROUND AND AIMS

Prognosis of hepatoblastoma patients has increased with cisplatin-based chemotherapy and high-quality resection including liver transplant. Consequently current risk-adapted therapeutic strategy aims to reduce long-term side effects in patients with standard risk disease.

METHODS

We report long-term mortality and morbidity data concerning 151 2-year hepatoblastoma survivors treated with SIOPEL risk-adapted strategies (sex-ratio M/F = 1.6, median age at diagnosis = 2.6 years [range 0-17.7], median year at diagnosis = 2008 [1994-2017]). Fifty-three patients had loco-regional risk factors VPEFR, 12 were PRETEXT-IV and 30 were metastatic. All received cisplatin and 84 anthracyclines. Twelve had liver transplant. To assess hearing, renal and cardiac functions, audiograms were performed in 116/151 patients (76.8%), glomerular filtration rate in 113/151 (74.8%) and cardiac ultrasound in 65/84 (77.4%) anthracycline-exposed patients.

RESULTS

With a median follow-up of 9.4 years (range 2.1-25.8), four late relapses, one second malignancy (Acute Myeloid Leukemia AML-M5) and two deaths (one from hepatoblastoma, one from AML) occurred. The 10-years event free survival and overall survival probabilities were 95.5% (95% CI 91.9-99.1) and 98.7% (95% CI 96.8-100), respectively. Sixty-eight non-oncologic health-events included 57 cases of hearing loss (including 25 Brock 3-4), three liver cirrhosis, three pre-operative portal cavernoma, two focal nodular hyperplasia, two grade-1 chronic kidney diseases and one asymptomatic cardiac dysfunction were reported. Ototoxicity was significantly associated with cisplatin cumulative dose (OR = 2.07, 95% CI 1.32-3.24, p = 0.001) and carboplatin exposure (OR = 3.14, 95% CI 1.30-7.58, p = 0.01) in multivariable analysis adjusted for sex and age at diagnosis.

CONCLUSIONS

With current risk-adapted strategies, hepatoblastoma is a highly curable disease, with very rare relapses, and few late effects except hearing loss which remains a serious condition in these very young patients.

Late Kidney Effects of Childhood Cancer and Cancer Therapies

Childhood cancer therapy carries a high risk of treatment-related toxicities and complications that can impact kidney function. Although many of these adverse effects in the acute setting are well described, less is known about the latent effects of childhood cancer treatments on long-term kidney health. With decades of advancements in treatment protocols for many pediatric malignancies, more children than ever before are surviving into adulthood after being cured of their disease and with lower long-term morbidity. Although there is decreased prevalence of many chronic health conditions in cancer survivors, including gastrointestinal, endocrine, and musculoskeletal disorders, the long-term risk of kidney dysfunction has increased. In this review, we summarize the epidemiology of kidney disease in survivors of childhood cancer and describe the treatment-related risk factors associated with long-term impairment of kidney health. We organize this review by specific kidney disease-related outcomes of interest (chronic electrolyte abnormalities, CKD, proteinuria, and hypertension) to highlight what specific aspects of cancer treatment have been associated with these outcomes. Finally, we conclude by comparing different clinical practice guidelines that exist for long-term kidney function monitoring and include recommendations for when a childhood cancer survivor would benefit from long-term nephrology care.

Late-onset kidney failure in survivors of childhood cancer: a report from the Childhood Cancer Survivor Study

BACKGROUND

The incidence of and risk factors for late-onset kidney failure among survivors over the very long term remains understudied.

MATERIALS AND METHODS

A total of 25,530 childhood cancer survivors (median follow-up 22.3 years, interquartile range 17.4-28.8) diagnosed between 1970 and 1999, and 5045 siblings from the Childhood Cancer Survivor Study were assessed for self-reported late-onset kidney failure, defined as dialysis, renal transplantation, or death attributable to kidney disease. Piecewise exponential models evaluated associations between risk factors and the rate of late-onset kidney failure.

RESULTS

A total of 206 survivors and 10 siblings developed late-onset kidney failure, a 35-year cumulative incidence of 1.7% (95% confidence interval [CI] = 1.4-1.9) and 0.2% (95% confidence interval [CI] = 0.1-0.4), respectively, corresponding to an adjusted rate ratio (RR) of 4.9 (95% CI = 2.6-9.2). High kidney dose from radiotherapy (≥15Gy; RR = 4.0, 95% CI = 2.1-7.4), exposure to high-dose anthracycline (≥250 mg/m2; RR = 1.6, 95% CI = 1.0-2.6) or any ifosfamide chemotherapy (RR = 2.6, 95% CI = 1.2-5.7), and nephrectomy (RR = 1.9, 95% CI = 1.0-3.4) were independently associated with elevated risk for late-onset kidney failure among survivors. Survivors who developed hypertension, particularly in the context of prior nephrectomy (RR = 14.4, 95% CI = 7.1-29.4 hypertension with prior nephrectomy; RR = 5.9, 95% CI = 3.3-10.5 hypertension without prior nephrectomy), or diabetes (RR = 2.2, 95%CI = 1.2-4.2) were also at elevated risk for late-onset kidney failure.

CONCLUSIONS

Survivors of childhood cancer are at increased risk for late-onset kidney failure. Kidney dose from radiotherapy ≥15 Gy, high-dose anthracycline, any ifosfamide, and nephrectomy were associated with increased risk of late-onset kidney failure among survivors. Successful diagnosis and management of modifiable risk factors such as diabetes and hypertension may mitigate the risk for late-onset kidney failure. The association of late-onset kidney failure with anthracycline chemotherapy represents a novel finding that warrants further study.

Childhood Cancer and the Risk of ESKD

BACKGROUND

Increasing cancer incidence among children alongside improved treatments has resulted in a growing number of pediatric cancer survivors. Despite childhood cancer survivors' exposure to various factors that compromise kidney function, few studies have investigated the association between childhood cancer and future kidney disease.

METHODS

To assess the risk of ESKD among childhood cancer survivors, we conducted a nationwide, population-based, retrospective cohort study that encompassed all Israeli adolescents evaluated for mandatory military service from 1967 to 1997. After obtaining detailed histories, we divided the cohort into three groups: participants without a history of tumors, those with a history of a benign tumor (nonmalignant tumor with functional impairment), and those with a history of malignancy (excluding kidney cancer). This database was linked to the Israeli ESKD registry to identify incident ESKD cases. We used Cox proportional hazards models to estimate the hazard ratio (HR) of ESKD.

RESULTS

Of the 1,468,600 participants in the cohort, 1,444,345 had no history of tumors, 23,282 had a history of a benign tumor, and 973 had a history of malignancy. During a mean follow-up of 30.3 years, 2416 (0.2%) participants without a history of tumors developed ESKD. Although a history of benign tumors was not associated with an increased ESKD risk, participants with a history of malignancy exhibited a substantially elevated risk for ESKD compared with participants lacking a history of tumors, after controlling for age, sex, enrollment period, and paternal origin (adjusted HR, 3.2; 95% confidence interval, 1.3 to 7.7).

CONCLUSIONS

Childhood cancer is associated with an increased risk for ESKD, suggesting the need for tighter and longer nephrological follow-up.

Urine NGAL and KIM-1-Tubular Injury Biomarkers in Long-Term Survivors of Childhood Solid Tumors: A Cross-Sectional Study

The deterioration of renal function after childhood solid tumors treatment is the result of using the intensive multimodal therapy. In recent years, urinary kidney injury molecule-1 (KIM-1) and urinary neutrophil gelatinase-associated lipocalin (NGAL) have been introduced as potential promising biomarkers of early kidney damage. The aim of the present study was to determine whether anticancer treatment has any effect on the concentration of KIM-1 and NGAL and its association with renal impairment in survivors of childhood solid tumors. Sixty patients previously treated for solid tumors were involved in this study. The median time after end of treatment was 8.35 years. Urine KIM-1 and NGAL levels were measured using immunoenzymatic ELISA commercial kits. Higher levels of urine NGAL, KIM-1/cr. (creatinine), and NGAL/cr. ratios were found in comparison with healthy controls (p < 0.0001). Among all subjects, 23% were found to have decreased estimated glomerular filtration rate (eGFR). A strong correlation between KIM-1/cr. and a cumulative dose of ifosfamide was observed (r = 0.865, p < 0.05). In addition, a moderate correlation between NGAL/cr. and a cumulative dose of cisplatin was identified (r = 0.534, p < 0.05). The AUC for KIM-1/cr. was 0.52, whereas NGAL/cr. showed a diagnostic profile describing the AUC of 0.67. Univariable regression showed significant associations between NGAL/cr. ratio and subjects after unilateral nephrectomy (coeff. 63.8, p = 0.007), cumulative dose of cisplatin (coeff. 0.111, p = 0.033), and age at diagnosis (coeff. 3.75, p = 0.023). The multivariable model demonstrated only cumulative dose of cisplatin as an independent factor influence on NGAL/cr. ratio. The results of our study showed increased levels of urine KIM-1 and NGAL many years after completion of the childhood solid tumors treatment, which correlated positively with a cumulative dose of ifosfamide and cisplatin. This study also suggests that unilateral nephrectomy could affect the concentration of the studied biomarkers.

Renal and Hepatic Health After Childhood Cancer

Childhood cancer survivors (CCSs) are at risk for renal and hepatic complications related to curative cancer treatments. Although acute renal and hepatic toxicities of cancer treatments are well described, data regarding long-term and late-occurring sequelae or their associations with acute sequelae are less robust. This article highlights the literature on the prevalence of and risk factors for late renal and hepatic toxicity in CCSs. Studies investigating these outcomes are needed to inform surveillance practices and the development of future frontline cancer treatment protocols.

Urine NGAL and KIM-1: tubular injury markers in acute lymphoblastic leukemia survivors

Introduction

Nephrotoxicity is a potential adverse effect of anticancer treatment in childhood. Cytostatics, abdominal radiotherapy, total body irradiation (TBI) and some agents used in supportive care may induce acute kidney injury (AKI) or lead to chronic kidney disease (CKD). The aim of this study was to test the hypothesis whether urinary kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are increased in acute lymphoblastic leukemia (ALL) survivors.

Method

The study cohort consisted of 86 patients (42 females) previously treated for ALL. The median time after cessation of treatment was 6.55 (IQR: 1.96–9.93) years and median age at the time of study: 12 (IQR: 6.76–16.00). The control group included 53 healthy peers. Immunoenzymatic ELISA commercial kits were used to measure urine KIM-1 and NGAL levels.

Results

The median levels of urine uNGAL (p < 0.05), uNGAL/creatinine (cr.) ratio (p < 0.0001) and uKIM-1/creatinine ratio (p < 0.0001) were significantly higher in ALL survivors in comparison with healthy controls. Female patients had significantly higher levels of NGAL and NGAL/cr. than males (mean 8.42 ± 7.1 vs. 4.59 ± 4.5 ng/mL and 86.57 ± 77 vs. 37.7 ± 37 ng/mg, respectively; p < 0.01). Of all the study participants, 11 (13%) presented eGFR below 90 mL/min/1.73 m². The NGAL/cr. ratio seemed to be the best predictor of decreased eGFR (AUC = 0.65). The cumulative dose of methotrexate and cyclophosphamide did not predict the values of the urine NGAL, NGAL/cr., KIM-1/cr. and eGFR.

Five years after the end of treatment, the patients had higher levels of uKIM-1 (1.02 ± 0.8 vs. 0.62 ± 0.6 ng/mL, p < 0.01), uNGAL (7.9 ± 6.7 vs. 4.6 ± 5 ng/mL, p < 0.01) and lower eGFR (114 ± 29 vs. 134 ± 35 mL/min/1.73 m², p < 0.01) in comparison with ALL survivors with the observation period of less than 5 years.

Conclusion

We demonstrated that ALL survivors have higher levels of urine NGAL, NGAL/cr. and uKIM-1/cr. ratio as compared to the control group. Further long-term follow-up studies are necessary to assess the significance of the NGAL and KIM-1 and their relationship to kidney damage after anticancer treatment in childhood.

Long-term complications of acute kidney injury in children

PURPOSE OF REVIEW

The current review will describe the current evidence and mechanisms of acute kidney injury (AKI) as a risk factor for long-term kidney complications, summarize the rationale for AKI follow-up and present an approach to monitoring children with AKI. Despite emerging evidence linking AKI with risk for long-term kidney and cardiovascular outcomes, many children who develop AKI are not followed for kidney disease development after hospital discharge. Better understanding of long-term complications after AKI and practical algorithms for follow-up will hopefully increase the rate and quality of post-AKI monitoring.

RECENT FINDINGS

Recent evidence shows that pediatric AKI is associated with long-term renal outcomes such as chronic kidney disease (CKD) and hypertension, both known to increase cardiovascular risk. The mechanism of AKI progression to CKD involves maladaptive regeneration of tubular epithelial and endothelial cells, inflammation, fibrosis and glomerulosclerosis. Many AKI survivors are not followed, and no guidelines for pediatric AKI follow-up have been published.

SUMMARY

Children who had AKI are at increased risk of long-term renal complications but many of them are not monitored for these complications. Recognizing long-term outcomes post-AKI and integration of follow-up programs may have a long-lasting positive impact on patient health.

Risk factors for premature aging in childhood cancer survivors

Over the last decades, the overall survival rate for childhood cancer has increased from 20% to 80%, which is the result of advances in treatment. Nevertheless, most data from the international registers of childhood cancer survivors (CCS) stress that this population of patients is at high risk for late sequelae and their biological aging starts earlier in life. Anticancer therapy (chemotherapy, radiotherapy, surgery, immunotherapy) affects the intracellular processes leading to the chronic deterioration of organ function and premature senescence. The present review focuses on the late effects of anticancer treatment on various human organs that may lead to premature aging.

Disease-specific Hospitalizations Among 5-Year Survivors of Hepatoblastoma: A Nordic Population-based Cohort Study

INTRODUCTION

The long-term risk of somatic disease in hepatoblastoma survivors has not been thoroughly evaluated in previous studies. In this population-based study of 86 five-year HB survivors, we used inpatient registers to evaluate the risk for a range of somatic diseases.

METHODS

In total, 86 five-year survivors of hepatoblastoma were identified in the Nordic cancer registries from 1964 to 2008 and 152,231 population comparisons were selected. Study subjects were followed in national hospital registries for somatic disease classified into 12 main diagnostic groups. Standardized hospitalization rate ratios (RRs) and absolute excess risks were calculated.

RESULTS

After a median follow-up of 11 years, 35 of the 86 five-year hepatoblastoma survivors had been hospitalized with a total of 69 hospitalizations, resulting in an RR of 2.7 (95% confidence interval [CI], 2.2-3.5) and an overall absolute excess risk of 4.2 per 100 person-years. Highest risk was seen for benign neoplasms (RR=16) with 6 hospitalizations for benign neoplasms in the colon and one in rectum.

CONCLUSIONS

The pattern of hospitalizations found in this first comprehensive follow-up of hepatoblastoma survivors seems reassuring. Less than 50% of the 5-year survivors had been hospitalized and often for diseases that were not severe or life-threatening.

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.

[Renal toxicity of high-dose methotrexate]

INTRODUCTION

High-dose methotrexate (at least 1g/m²) is used to treat haematologic malignancies and osteosarcomas. Acute kidney injury is a well-known adverse-event after high-dose methotrexate and may lead to delayed drug elimination. Besides usual therapeutics (hyperhydration, urine alkalinisation, leucovorin rescue, renal replacement therapy), a costly specific enzymatic treatment (glucarpidase) is now available but its clinical impact remains elusive.

PATIENTS AND METHODS

We analysed high-dose methotrexate prescription charts in 11 clinical centres during the last 15 years to identify and describe adult patients who developed acute kidney injury (according to KDIGO classification). Glucarpidase use was recorded (French temporary regulatory approval criteria: methotrexate at least 10μmol/L at 48h or at least 3μmol/L at 48h associated with acute kidney injury).

RESULTS

Seventy-six acute kidney injury cases have been studied. Mean peak creatinine was 206μmol/L after a mean delay of 5.6 days, with 19 cases of stage 1 acute kidney injury (25%), 29 cases of stage 2 (38%) and 27 cases of stage 3 (36%). Anuria (one case) and need for renal replacement therapy (four cases) were unusual whereas fluid overload was often observed (29%). Three months after high-dose methotrexate treatment, mortality-rate was 17%, and 12% of surviving patients developed renal sequelae.

CONCLUSION

Sixty-one percent of patients received a glucarpidase perfusion during acute kidney injury. Despite a dramatic decrease of methotrexate serum levels, glucarpidase as compared with conservative treatment did not modify acute kidney injury stage, recovery delay, need for renal replacement therapy or the incidence of extrarenal toxicities. Net clinical benefit was not observed even after stratification according to eligibility criteria for glucarpidase use. Glucarpidase has probably no or little effects on methotrexate localized into tubular lumen or proximal tubular cells and that may account for the absence of nephroprotective effect for enzymatic treatment.

Renal function up to the 5th decade of life after nephrectomy in childhood: A literature review

The aim of the present study was to find out if in children ablation of 50% of renal mass may be associated with a progressive renal damage (Brenner's hypothesis). We collected 1035 adult or adolescent survivors who underwent nephrectomy for unilateral oncological or non-oncological causes during childhood. Stratification of all survivors for age revealed that the number of subjects with blood hypertension and/or renal dysfunction (glomerular filtration rate < 90 mL/min per 1.73 m² ) to be significantly higher in survivors ≥30 years old in comparison with younger patients. Available data on long-term renal function after nephrectomy during childhood support the Brenner's hypothesis.

Cisplatin nephrotoxicity as a model of chronic kidney disease

Cisplatin (CP)-induced nephrotoxicity is widely accepted as a model for acute kidney injury (AKI). Although cisplatin-induced chronic kidney disease (CKD) in rodent has been reported, the role of phosphate in the cisplatin-induced CKD progression is not described. In this study, we gave a single peritoneal injection of CP followed by high (2%) phosphate diet for 20 weeks. High dose CP (20 mg/Kg) led to high mortality; whereas a lower dose (10 mg/Kg) resulted in a full spectrum of AKI with tubular necrosis, azotemia, and 0% mortality 7 days after CP injection. After consuming a high phosphate diet, mice developed CKD characterized by low creatinine clearance, interstitial fibrosis, hyperphosphatemia, high plasma PTH and FGF23, low plasma 1,25(OH)₂ Vitamin D₃ and αKlotho, and classic uremic cardiovasculopathy. The CP model was robust in demonstrating the effect of aging, sexual dimorphism, and dietary phosphate on AKI and also AKI-to-CKD progression. Finally, we used the CP-high phosphate model to examine previously validated methods of genetically manipulated high αKlotho and therapy using exogenous soluble αKlotho protein supplementation. In this CP CKD model, αKlotho mitigated CKD progression, improved mineral homeostasis, and ameliorated cardiovascular disease. Taken together, CP and high phosphate nephrotoxicity is a reproducible and technically very simple model for the study of AKI, AKI-to-CKD progression, extrarenal complications of CKD, and for evaluation of therapeutic efficacy.

Long-term renal function and hypertension in adult survivors of childhood sarcoma: Single center experience

AIM

Little data is available on long-term renal impairment in survivors from childhood sarcoma. We investigated the prevalence of renal impairment and hypertension after very long-term follow-up in survivors who reached adulthood after treatment for childhood sarcoma.

METHODS

A cross-sectional single center study was performed. Outcomes included estimating glomerular filtration rate (eGFR), albuminuria, glycosuria, serum phosphate and magnesium, tubular reabsorption phosphate (TRP), chronic kidney disease (CKD) according to the "Kidney Disease: Improving Global Outcomes" (KDIGO) guidelines and blood pressure (BP).

RESULTS

Out of 87 > 5-year sarcoma survivors, 30 adults (10F/20M, median age at diagnosis 9 years, median age at investigation 26 years, median follow-up 16 years, mean 19 years) were identified. Renal impairment was detected in four cases (13.3%); three of these fulfilled the criteria for CKD. Among the adult survivors, a subgroup of 15 cases (50%) had received ifosfamide without confounding factors such as a diagnosis of genito-urinary rhabdomyosarcoma or administration of other potentially nephrotoxic chemotherapy (platinum-based drugs or methotrexate); no renal dysfunction was detected in this subgroup. In the whole cohort of sarcoma survivors, hypertension was diagnosed in four cases (13.3%); BP was significantly correlated with body mass index [p .014].

CONCLUSION

In our series of adult survivors treated for a diagnosis of sarcoma in their childhood, the prevalence of CKD was 10%. We found survivors treated with ifosfamide as the only nephrotoxic agent did not present glomerular or tubular toxicity at long term follow-up, but further studies including a larger number of cases are required to confirm it.

Late renal toxicity of treatment for childhood malignancy: risk factors, long-term outcomes, and surveillance

Chronic glomerular and tubular nephrotoxicity is reported in 20-50% and 20-25%, respectively, of children and adolescents treated with ifosfamide and 60-80% and 10-30%, respectively, of those given cisplatin. Up to 20% of children display evidence of chronic glomerular damage after unilateral nephrectomy for a renal tumour. Overall, childhood cancer survivors have a ninefold higher risk of developing renal failure compared with their siblings. Such chronic nephrotoxicity may have multiple causes, including chemotherapy, radiotherapy exposure to kidneys, renal surgery, supportive care drugs and tumour-related factors. These cause a wide range of chronic glomerular and tubular toxicities, often with potentially severe clinical sequelae. Many risk factors for developing nephrotoxicity, mostly patient and treatment related, have been described, but we remain unable to predict all episodes of renal damage. This implies that other factors may be involved, such as genetic polymorphisms influencing drug metabolism. Although our knowledge of the long-term outcomes of chronic nephrotoxicity is increasing, there is still much to learn, including how we can optimally predict or achieve early detection of nephrotoxicity. Greater understanding of the pathogenesis of nephrotoxicity is needed before its occurrence can be prevented.

Renal toxicity and chemotherapy in children with cancer

The clinical use of antineoplastic drugs can be limited by different drug-induced toxicities. Of these, renal dysfunction may be one of the most troublesome in that it can be cumulative and in general is only partially reversible with the discontinuation of the treatment. Renal toxicity may be manifested as a reduction of the glomerular filtration rate, electrolyte imbalances, or acute renal failure. Careful assessment of renal function has to be performed taking into account that the impairment of renal function is initially silent and only later may be clinically dramatic. When clinically indicated, the reduction or, in cases of severe nephrotoxicity, the suspension of chemotherapy should be considered to avoid the progressive deterioration of the compromised glomerular and/or tubular function.

Optimising the use of medicines to reduce acute kidney injury in children and babies

The majority of medications in children are administered in an unlicensed or off-label manner. Paediatricians are obliged to prescribe using the limited evidence available. The 2007 EU regulation on the use of paediatric drugs means pharmaceutical companies are now obliged to (and receive incentives for) contributing to paediatric drug data and carrying out paediatric clinical trials. This is important, as the efficacy and adverse effect profiles of medicines vary across childhood. Additionally, there are significant age-related changes in the pharmacodynamic and pharmacokinetic activity of many drugs. This may be related to physiological (differential expressions of cytochrome P450 enzymes or variable glomerular filtration rates at different ages for example) and psychological (increasing autonomy and risk perception in teenage years) changes. Increasing numbers of children are surviving life-threatening childhood conditions due to medical advances. This means there is an increasing population who are at risk of the consequences of the long-term, early exposure to nephrotoxic agents. The kidney is an organ that is particularly vulnerable to damage as a consequence of drugs. Drug-induced acute kidney injury (AKI) episodes in children and babies are principally due to non-steroidal anti-inflammatory drugs, antibiotics or chemotherapeutic agents. The renal tubules are vulnerable to injury because of their concentrating ability and high-energy hypoxic environment. This review focuses on drug-induced AKI and the methods to minimise its effect, including general management plus the role of child-specific pharmacokinetic data, the use of pharmacogenomics and early detection of AKI using urinary biomarkers and electronic triggers.

Preventing and Managing Toxicities of High-Dose Methotrexate

: High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used to treat a range of adult and childhood cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI) in 2%-12% of patients. Nephrotoxicity results from crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. AKI and other toxicities of high-dose methotrexate can lead to significant morbidity, treatment delays, and diminished renal function. Risk factors for methotrexate-associated toxicity include a history of renal dysfunction, volume depletion, acidic urine, and drug interactions. Renal toxicity leads to impaired methotrexate clearance and prolonged exposure to toxic concentrations, which further worsen renal function and exacerbate nonrenal adverse events, including myelosuppression, mucositis, dermatologic toxicity, and hepatotoxicity. Serum creatinine, urine output, and serum methotrexate concentration are monitored to assess renal clearance, with concurrent hydration, urinary alkalinization, and leucovorin rescue to prevent and mitigate AKI and subsequent toxicity. When delayed methotrexate excretion or AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase are usually sufficient to allow renal recovery without the need for dialysis. Prompt recognition and effective treatment of AKI and associated toxicities mitigate further toxicity, facilitate renal recovery, and permit patients to receive other chemotherapy or resume HDMTX therapy when additional courses are indicated.

IMPLICATIONS FOR PRACTICE

High-dose methotrexate (HDMTX), defined as a dose higher than 500 mg/m2, is used for a range of cancers. Although HDMTX is safely administered to most patients, it can cause significant toxicity, including acute kidney injury (AKI), attributable to crystallization of methotrexate in the renal tubular lumen, leading to tubular toxicity. When AKI occurs despite preventive strategies, increased hydration, high-dose leucovorin, and glucarpidase allow renal recovery without the need for dialysis. This article, based on a review of the current associated literature, provides comprehensive recommendations for prevention of toxicity and, when necessary, detailed treatment guidance to mitigate AKI and subsequent toxicity.

Image-defined risk factors for nephrectomy in patients undergoing neuroblastoma resection

BACKGROUND

Although nephrectomy rates are higher in children with neuroblastoma who have image-defined risk factors and/or high-risk disease who undergo resection prior to chemotherapy, no published data outline the key radiographic and clinical characteristics associated with nephrectomy.

METHODS

With IRB approval, imaging studies of children undergoing primary resection of intraabdominal neuroblastoma between 2000 and 2014 were retrospectively reviewed. Fisher's exact and Wilcoxon rank-sum tests were used to compare categorical and continuous variables, respectively, with p-values adjusted for multiple testing using the false discovery rate approach.

RESULTS

Twenty-seven of 380 consecutive patients with CT imaging obtained prior to primary neuroblastoma resection underwent partial or total nephrectomy. On preoperative imaging, renal vessel narrowing and encasement and tumor invasion of the renal hilum, pelvis, and/or parenchyma were present significantly more frequently among patients undergoing nephrectomy. Delayed renal excretion of contrast, hydronephrosis, and tumors with MYCN amplification were also more prevalent in the nephrectomy group.

CONCLUSION

Encasement and narrowing of renal vessels, delayed excretion, and tumor invasion into the kidney, particularly pelvis and capsule invasion, are significantly associated with partial or total nephrectomy at initial neuroblastoma resection. These observations provide valuable information for surgical planning as well as presurgical discussions with families prior to neuroblastoma resection.

Long-term renal function in unilateral non-syndromic renal tumor survivors treated according to International Society of Pediatric Oncology protocols

BACKGROUND

The risk of renal impairment among survivors of childhood unilateral non-syndromic renal tumors (RTs) is not well defined. We evaluated the prevalence of and possible risk factors for renal impairment by estimating Glomerular Filtration Rate (eGFR) categories and chronic kidney disease (CKD) according to Kidney Disease: Improving Global Outcomes guidelines.

PROCEDURE

Since 1978, 82 patients were treated for RT, according to the International Society of Pediatric Oncology protocols in a single oncology unit. Of the 67 survivors, those who underwent nephron sparing surgery, those with short-term follow-up or those who had bilateral and/or syndromic disease or a second malignancy were excluded. Thirty-five adult survivors (14 M/21F; mean age 25 years; mean follow-up 20 years) were studied by chemistry, kidney ultrasound, blood pressure measurement, urinanalysis. Correlations were investigated between the prevalence of eGFR categories and CKD and gender, age at diagnosis, radiotherapy, chemotherapy, body mass index, time of follow-up, and age at study.

RESULTS

Eight (22.9%) survivors presented a mildly decreased eGFR (G2 category), the mean value was 80 ± 9.78 ml/min/1.73m(2) (median 84.5, range 63-89). Three (8.6%) survivors had CKD and a fourth (2.9%) hypertension. No significant correlations between G2 category and clinical variables were found.

CONCLUSIONS

A small percentage of survivors had CKD or hypertension after two decades. It is not yet clear whether a mildly decreased eGFR that does not constitute CKD in the absence of other markers (albuminuria and/or kidney ultrasound abnormalities) is likely to progress to CKD. Health promotion programs to avoid comorbidities are required.

Subclinical hypothyroidism as a rare cofactor in chronic kidney disease (CKD) - related anemia

BACKGROUND

Both chronic kidney disease (CKD) and hypothyroidism may cause anemia. However, the combination of the three above-mentioned phenomena in children has not been described yet.

METHODS

Our aim was to present a case of a 16-year-old girl hospitalized due to the renal impairment in the course of chemotherapy. Chronic kidney disease and severe anemia were diagnosed and erythropoiesis-stimulating agents (ESA) were administered. In view of unsatisfactory therapeutic effect, rare potential causes of hyporesponsiveness to ESA were analyzed. Laboratory tests revealed subclinical hypothyroidism. The thyroid hormone replacement therapy was applied and normalization of thyroid function was observed. Further increase of hemoglobin levels permitted discontinuation of ESA treatment. At the same time, partial amelioration of kidney function, as well as clinical improvement, were noticed.

CONCLUSION

The thyroid gland function should be assessed both in differential diagnostics of anemia and in case of unsatisfactory treatment with ESA.

Late new morbidity in survivors of adolescent and young-adulthood brain tumors in Finland: a registry-based study

BACKGROUND

Brain tumors (BTs) in adolescence and young adulthood (AYA) differ from those in childhood or late adulthood. However, research concerning late effects in this particular survivor group is limited. This study evaluates late morbidity of survivors diagnosed in AYAs.

METHODS

We identified from the Finnish Cancer Registry all survivors diagnosed with BT at the ages 16-24 years between 1970 and 2004 (N = 315) and used data from the Hospital Discharge Registry to evaluate their late (≥5 y after diagnosis) morbidity requiring treatment in a specialized health care setting. A sibling cohort of BT patients diagnosed before the age of 25 years was used as a comparison cohort (N = 3615).

RESULTS

The AYA BT survivors had an increased risk for late-appearing endocrine diseases (HR, 2.9; 95% CI, 1.1-8.0), psychiatric disorders (HR, 2.0; 95% CI, 1.2-3.2), diseases of the nervous system (HR, 9; 95% CI, 6.6-14.0), disorders of vision/hearing loss (HR, 3.6; 95% CI, 1.5-8.5), diseases of the circulatory system (HR, 4.9; 95% CI, 2.9-8.1), and diseases of the kidney (HR, 5.9; 95% CI, 2.5-14.1). Survivors with irradiation had an increased risk for diseases of the nervous system compared with non-irradiated survivors (HR, 3.3; 95% CI, 1.8-6.2). The cumulative prevalence for most of the diagnoses remained significantly increased for survivors even 20 years after cancer diagnosis.

CONCLUSIONS

The AYA BT survivors have an increased risk of morbidity for multiple new outcomes for ≥5 years after their primary diagnosis. This emphasizes the need for structured late-effect follow-up for this patient group.

Late morbidity in long-term survivors of childhood brain tumors: a nationwide registry-based study in Finland

BACKGROUND

The population of long-term survivors of childhood brain tumors (BTs) is growing. The aim of our study was to evaluate late-appearing morbidity in BT survivors.

METHODS

Patients diagnosed with a BT at the age of 0-15 years between 1970 and 2004, and surviving at least 5 years, were identified from the Finnish Cancer Registry (n = 740). Their late new morbidity ≥ 5 years after cancer diagnosis was assessed using the Hospital Discharge Registry containing hospitalizations and outpatient visits in specialized health care settings. The morbidity of BT survivors was compared with that of the sibling cohort (n = 3615).

RESULTS

The 5-year survivors had a significantly increased hazard ratio (HR) for endocrine diseases (HR, 14.7), psychiatric disorders (HR, 1.8), cognitive and developmental disorders (HR, 16.6), neurological diseases (HR, 9.8), disorders of vision and hearing (HR, 10.5), and diseases of the circulatory system (HR, 2.7) compared with the sibling cohort. The HRs for disorders of musculoskeletal system (HR, 1.4) and diseases of the kidney (HR, 2.1) were not significantly increased. Radiation treatment did not explain all of the excess morbidity. Female survivors had a higher risk for disorders of vision and hearing (P = .046). Age at diagnosis did not show an effect on HRs. The HRs for endocrine diseases and disorders of vision or hearing loss were highest for survivors treated in the 1980s or later.

CONCLUSIONS

Pediatric BT survivors had significant neurocognitive consequences. This, together with the considerable risk for endocrine morbidity, will motivate us to organize systematic follow-up procedures for pediatric BT survivors.