Renal size and function after cure of Wilms' tumour

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.

Development and Validation of a Prediction Model for Kidney Failure in Long-Term Survivors of Childhood Cancer

PURPOSE

Kidney failure is a rare but serious late effect following treatment for childhood cancer. We developed a model using demographic and treatment characteristics to predict individual risk of kidney failure among 5-year survivors of childhood cancer.

METHODS

Five-year survivors from the Childhood Cancer Survivor Study (CCSS) without history of kidney failure (n = 25,483) were assessed for subsequent kidney failure (ie, dialysis, kidney transplantation, or kidney-related death) by age 40 years. Outcomes were identified by self-report and linkage with the Organ Procurement and Transplantation Network and the National Death Index. A sibling cohort (n = 5,045) served as a comparator. Piecewise exponential models accounting for race/ethnicity, age at diagnosis, nephrectomy, chemotherapy, radiotherapy, congenital genitourinary anomalies, and early-onset hypertension estimated the relationships between potential predictors and kidney failure, using area under the curve (AUC) and concordance (C) statistic to evaluate predictive power. Regression coefficient estimates were converted to integer risk scores. The St Jude Lifetime Cohort Study and the National Wilms Tumor Study served as validation cohorts.

RESULTS

Among CCSS survivors, 204 developed late kidney failure. Prediction models achieved an AUC of 0.65-0.67 and a C-statistic of 0.68-0.69 for kidney failure by age 40 years. Validation cohort AUC and C-statistics were 0.88/0.88 for the St Jude Lifetime Cohort Study (n = 8) and 0.67/0.64 for the National Wilms Tumor Study (n = 91). Risk scores were collapsed to form statistically distinct low- (n = 17,762), moderate- (n = 3,784), and high-risk (n = 716) groups, corresponding to cumulative incidences in CCSS of kidney failure by age 40 years of 0.6% (95% CI, 0.4 to 0.7), 2.1% (95% CI, 1.5 to 2.9), and 7.5% (95% CI, 4.3 to 11.6), respectively, compared with 0.2% (95% CI, 0.1 to 0.5) among siblings.

CONCLUSION

Prediction models accurately identify childhood cancer survivors at low, moderate, and high risk for late kidney failure and may inform screening and interventional strategies.

Increased risk for kidney sequelae surrogates in survivors of Wilms tumor

BACKGROUND

There is evidence of increased risk of hypertension, albuminuria, and development of chronic kidney disease (CKD) in long-term follow-up of survivors of Wilms tumor (WT). However, most studies were conducted in heterogeneous groups, including patients with solitary kidney. In addition, little is known about tubular dysfunction. This study aimed to investigate kidney sequelae, including CKD development, hypertension, and glomerular and tubular damage in WT survivors.

METHODS

This cross-sectional, single-center study included 61 patients treated for WT. Surrogates for kidney sequelae were defined as presence of at least one of the following: decrease in GFR for CKD, hypertension detected by ambulatory blood pressure monitoring, albuminuria (albumin-to-creatinine ratio [ACR] > 30 mg/g), or increase in at least one tubular biomarker (beta-2-microglobulin, neutrophil gelatinase-associated lipocalin, kidney injury marker-1, and liver fatty acid-binding protein) in 24-h urine.

RESULTS

Median age of patients was 11.7 years, with median follow-up of 8.8 years. Thirty-eight patients (62%) had at least one surrogate for kidney sequelae. Twenty-four patients (39%) had CKD, 14 patients (23%) had albuminuria, 12 patients (21%) had hypertension, and 11 patients (18%) had tubular damage. Urine ACR was significantly higher in patients with advanced tumor stage and patients with nephrotoxic therapy than their counterparts (p < 0.05), but neither eGFR nor tubular biomarkers showed any association with tumor- or treatment-related factors.

CONCLUSIONS

A considerable number of patients with WT have kidney sequelae, especially early-stage CKD with a high prevalence. Albuminuria emerges as a marker associated with tumor stages and nephrotoxic treatment. A higher resolution version of the Graphical abstract is available as Supplementary information.

Evaluation of cardiovascular risk in children with solitary functioning kidney

BACKGROUND

The present study investigates cardiovascular risk and kidney damage in patients with solitary kidneys.

METHODS

Included in the study were 40 children with a unilateral functioning kidney and 60 healthy controls, all of whom were evaluated for carotid intima-media thickness, ischemia-modified albumin and oxidative stress parameters, and 24-h ambulatory blood pressure monitoring.

RESULTS

Serum creatinine and urine microalbumin levels were higher and creatinine clearance was lower in the patient group than in the control group, and serum ischemia-modified albumin, carotid intima-media thickness, aldosterone, plasma renin activity and blood pressure were all higher in the patient group than in the control group. In addition, the patient group was showed a non-dipper pattern.

CONCLUSION

Children with a normal functioning solitary kidney are likely at higher risk of developing cardiovascular disease and such patients should be followed closely before marked kidney impairment occurs.

Outcomes of kidney injury including dialysis and kidney transplantation in pediatric oncology and hematopoietic cell transplant patients

Pediatric oncology and hematopoietic cell transplant (HCT) patients are susceptible to both acute kidney injury (AKI) and chronic kidney disease (CKD). The etiologies of AKI vary but include tumor infiltration, radiation, drug-induced toxicity, and fluid and electrolyte abnormalities including tumor lysis syndrome. HCT patients can also have additional complications such as sinusoidal obstructive syndrome, graft-versus-host disease, or thrombotic microangiopathy. For patients with severe AKI requiring dialysis, multiple modalities can be used successfully, although continuous kidney replacement therapy (CKRT) is often the principal modality for critically ill patients. While increasing numbers of pediatric cancer and HCT patients are now surviving long term, they remain at risk for a number of chronic medical conditions, including CKD. Certain high-risk patients, due to underlying risk factors or treatment-related complications, eventually develop kidney failure and may require kidney replacement therapies. Management of co-morbidities and complications associated with kidney failure, including use of erythropoietin for anemia and potential need for ongoing cancer-related treatment while on dialysis, is an additional consideration in this patient population. Kidney transplantation can be successfully performed in pediatric cancer survivors, although additional features such as specific cancer diagnosis and duration of remission should be considered.

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.

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 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.

Prospective analysis of long-term renal function in survivors of childhood Wilms tumor

BACKGROUND

Considering the improved outcome, a better understanding of the late effects in Wilms tumor survivors (WT-S) is needed. This study was aimed at evaluating renal function and determining the prevalence of clinical and subclinical renal dysfunction in a cohort of WT-S using a multimodal diagnostic approach.

METHODS

Thirty-seven WT-S were included in this prospective cross-sectional single center study. To evaluate renal function, glomerular filtration rate (GFR) and urinary protein excretion were assessed. Additionally, kidney sonomorphology and blood pressure were analyzed.

RESULTS

All examined WT-S (mean age 28.7 years, mean follow-up 24.8 years) had been treated with a combination of surgery and chemotherapy; 59.5% had received adjuvant radiotherapy. Impaired glomerular renal function was detected in a considerable proportion of WT-S, with age-adjusted cystatin-based GFR estimation below age norm in 55.9%. A lower cystatin-based estimated GFR (eGFR) correlated with longer follow-up time and higher irradiation dose. In 5 patients (13.5%) albuminuria was identified. Analysis of sonomorphology detected compensatory contralateral renal hypertrophy in 83.3% of WT-S. Chronic kidney disease (CKD) ≥ stage II was present in 55.9% of WT-S. Blood pressure measurements revealed arterial hypertension in 15 (40.5%) WT-S (newly diagnosed n=10). In 24.3% both CKD ≥ stage II and arterial hypertension were determined.

CONCLUSION

Even though WT-S are believed to carry a low risk for end-stage renal disease, in this study, a remarkable number of WT-S presented with previously unidentified subclinical signs of renal function impairment and secondary morbidity. Therefore, it is important to continue regular follow-up, especially after transition into adulthood.

Renal Late Effects After the Treatment of Unilateral Nonsyndromic Wilms Tumor

Wilms tumor is the most common renal malignancy of childhood. Because of the improvement in prognosis and the increase in survival rates, long-term consequences of the treatment for Wilms tumor are of greater concern. We investigated late renal effects of the treatment on 50 survivors of nonsyndromic unilateral Wilms tumor. After the second year since the cessation of treatment, the glomerular filtration rate (GFR), urinary protein excretion, urinary β2 microglobulin levels, and blood pressure as well as the general health status were assessed. Results were analyzed for correlation with clinical variables, chemotherapy, and radiotherapy as possible risk factors. At a median follow-up time of 8.8 years (mean=10.9; range, 2.3 to 35.4 y), none of the patients developed end-stage renal disease. Compensatory hypertrophy was observed in 68% of the cases. The median maximum bipolar length was significantly higher in patients diagnosed after the age of 36 months. Eleven (22%) and 2 (4%) of the 50 patients were hypertensive at the time of the diagnosis and the study, respectively. Similarly, median GFR values were significantly lower at the time of diagnosis, although at the time of the study, all patients had normal GFR values. With longer follow-up intervals, especially after 10 years, a significant decreasing trend in the GFR was observed (P=0.002).

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.

Function and size of the residual kidney after treatment of Wilms tumor

Long-term damage to the residual kidney is of concern in the survivors of Wilms tumor. Our objective was to evaluate the long-term glomerular function and size of the residual kidney in these patients. Twenty-nine survivors of Wilms tumor diagnosed between July 1999 and June 2004 were enrolled. The glomerular function was assessed by creatinine clearance, 99mTc DTPA radionuclide scintigraphy and 24-hour urinary protein. Renal size was evaluated by ultrasonography. Median age at diagnosis and at enrollment were 2.87 ± 1.8 (range: 0.5-7.5) and 7.9 ± 3.8 years (range: 2.5-18). Median duration of follow-up was 4.78 ± 2.6 years (range: 1-8.8). Evidence of renal dysfunction in the form of either function or size was identified in eight (27.6%) children. Six children had subnormal glomerular filtration rate and one had proteinuria. Subnormal size of the residual kidney was observed in one child. Age at diagnosis, stage, and duration elapsed after nephrectomy had no association with renal dysfunction (P >.05). Long-term follow up is crucial to identify clinical nephrotoxicity among survivors of Wilms tumor.

Evaluation of renal function after successful treatment for unilateral, non-syndromic Wilms tumor

Impaired renal function may occur in experimental animals following surgical removal of most functioning renal tissue ("hyperfiltration injury"). Although end-stage renal disease is uncommon among long-term survivors of unilateral, non-syndromic Wilms tumor, concern has been expressed that there may be an increased risk of less serious, but progressive, renal function impairment among these individuals. The recent development of equations for estimating glomerular filtration rate (eGFR) has facilitated the study of renal function in Wilms tumor survivors. However, the estimating equations were developed to categorize individuals with chronic kidney disease and have significant limitations with regard to the accuracy of individual GFR estimates. These limitations must be considered when utilizing the estimating equations in cross-sectional or longitudinal evaluations of renal function in cohorts of patients who have been treated successfully for Wilms tumor or other childhood cancers.

Renal function and low-molecular-weight proteins (cystatin C, β2-microglobulin, neutrophil gelatinase-associated lipocalin) in child and young adult cancer survivors

BACKGROUND

We sought to verify the hypothesis that children and young adults with cancer who have completed treatment differ according to the type and degree of renal damage.

PROCEDURE

This study included 144 children and young adults (73 female) who had completed treatment for leukemias and lymphomas (group L, n=45), Wilms tumor (group W, n=52) and other solid tumors (group S, n=47). The following parameters were evaluated: serum concentrations of creatinine, cystatin C, β2-microglobulin, neutrophil gelatinase-associated lipocalin and urine excretion of albumin, and urinalysis with sediment. Glomerular filtration rate (eGFR) was estimated using the classic Schwartz (eGFRSch), Schwartz redux (eGFRSchred), and Filler (eGFRFiller) formulas and with the new Schwartz equation for patients with chronic kidney disease (eGFRSchCKD).

RESULTS

Group S had the lowest eGFRSchCKD and eGFRFiller, the highest serum cystatin C and the highest albumin excretion compared with groups L and W. Groups S and W had lower eGFRSch and eGFRSchred and higher serum β2-microglobulin and neutrophil gelatinase-associated lipocalin compared with group L. Group W had lower eGFRSchCKD than group L.

CONCLUSIONS

Children and young adults with cancer who have completed treatment differ in the type and degree of renal damage they sustain.

Urinary endothelin-1-like immunoreactivity excretion in Wilms' tumor survivors

BACKGROUND

We evaluated urinary endothelin (ET)-1-like Immunoreactivity (uET-1 L) excretion in Wilms tumor (WT) survivors and investigated its relationships with glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Glomerular hemodynamics were also assessed by Gomez formulae.

METHODS

Seventeen WT survivors underwent renal sequential scintigraphy for residual kidney function determination including ERPF and GFR. Forty-five healthy individuals were selected as the control group. uET-1 L was measured by radioimmunoassay from the 24-h urine collection.

RESULTS

In WT survivors, uET-1 L excretion was significantly higher than in controls. Significant correlations were found between uET-1 L and ERPF and GFR. Cluster analysis, applied on uET-1 L, identified two different patient groups. Between them, GFR and ERPF were significantly different. No significant difference existed between the two clusters for age and sex, elapsed time from nephrectomy, treatment, or nephrectomy side. Applying Gomez formulae, significant difference was found for afferent and total renal resistance.

CONCLUSIONS

According to our results, uET-1 L seems to be a marker of glomerular injury in patients with renal mass loss revealing renal overload condition. The uET-1 L role in renal damage progression and hemodynamic glomerular worsening in nephrectomized patients should be proven by prospective long-term follow-up studies, even for potential ET-1 receptor antagonist therapeutic use.

Renal tumours: long-term outcome

Childhood cancer is rare, with an incidence of 100 new cases per million children and with renal tumours contributing 7% of cases. The introduction of multimodality treatment, surgery, radiotherapy and chemotherapy, has led to an exponential increase in the 5-year survival rate to >80%. However, this successful treatment has led to the development of late adverse effects. These treatment-related effects can cause premature deaths and increased morbidity compared with patients' peers. Radiation causes damage to tissue and organs within the radiation field, affecting growth and function, and is largely responsible for the leading cause of death, namely, second malignant neoplasms. Another important late effect is cardiac dysfunction due to anthracycline use with or without cardiac radiation. In addition, a few patients have genetic abnormalities predisposing to Wilms tumour development, which result in renal dysfunction in the long term and may be exacerbated by cancer treatment regimens. Awareness of late consequences of cancer treatment is important, as early recognition can improve outcome. When presented with a patient with a history of renal tumours, it is vital to enquire about previous treatment to understand whether it is relevant to the presenting problem.

Chronic kidney disease in children with unilateral renal tumor

PURPOSE

In patients who have undergone nephrectomy lower stage chronic kidney disease may develop, which is an independent risk factor for cardiovascular disease and overall mortality. We investigated whether the prevalence of lower stage chronic kidney disease is related to the amount of renal parenchyma excised in children with unilateral renal tumor.

MATERIALS AND METHODS

A total of 15 patients treated with nephrectomy and 10 treated with nephron sparing surgery were enrolled at a single academic center. The Kidney Disease Outcomes Quality Initiative guidelines were used to classify patients by chronic kidney disease stage based on estimated glomerular filtration rate values. The Modification of Diet in Renal Disease study equation and Schwartz equation were used in patients older and younger than 17 years, respectively.

RESULTS

At a mean followup of more than 12 years 8 patients who had undergone nephrectomy and 1 treated with bilateral nephron sparing surgery presented with stage II chronic kidney disease (estimated glomerular filtration rate 60 to 89 ml/min/1.73 m(2)). Sequential measurements from diagnosis to 12 to 17 years postoperatively showed that stage II chronic kidney disease in patients who had undergone nephrectomy manifested as a negligible postoperative increase in mean ± SD estimated glomerular filtration rate (75.7 ± 25.5 vs 79.4 ± 3.9 ml/min/1.73 m(2), p = 0.6). Five of the 8 patients presented with stage II chronic kidney disease even before nephrectomy. The other 7 patients who had undergone nephrectomy and those treated with nephron sparing surgery presented with a significant postoperative increase in mean ± SD estimated glomerular filtration rate (81.1 ± 24 vs 102.3 ± 3 ml/min/1.73 m(2), p = 0.02, and 88.7 ± 2 vs 107.4 ± 14 ml/min/1.73 m(2), p = 0.005, respectively).

CONCLUSIONS

A subset of children with unilateral renal tumor presents before and/or after nephrectomy, and not after nephron sparing surgery, with stage II chronic kidney disease, probably due to a reduced renal reserve capacity. Whether patients with preoperative renal dysfunction may benefit from nephron sparing surgery should be studied in a cooperative clinical trial setting.

Glomerular filtration rate and prevalence of chronic kidney disease in Wilms' tumour survivors

Glomerular filtration rate (GFR) was evaluated in 32 Wilms' tumour survivors (WTs) in a cross-sectional study using 99 Tc-diethylene triamine pentaacetic acid (99 Tc-DTPA) clearance, the Schwartz formula, the new Schwartz equation for chronic kidney disease (CKD), cystatin C serum concentration and the Filler formula. Kidney damage was established by beta-2-microglobulin (B-2-M) and albumin urine excretion, urine sediment and ultrasound examination. Blood pressure was measured. No differences were found between the mean GFR in 99 Tc-DTPA and the new Schwartz equation for CKD (91.8 ± 11.3 vs. 94.3 ± 10.2 ml/min/1.73 m(2) [p = 0.55] respectively). No differences were observed between estimated glomerular filtration rate (eGFR) using the Schwartz formula and the Filler formula either (122.3 ± 19.9 vs. 129.8 ± 23.9 ml/min/1.73 m(2) [p = 0.28] respectively). Increased urine albumin and B-2-M excretion, which are signs of kidney damage, were found in 7 (22%) and 3 (9.4%) WTs respectively. Ultrasound signs of kidney damage were found in 14 patients (43%). Five patients (15.6%) had more than one sign of kidney damage. Eighteen individuals (56.25%) had CKD stage I (10 with signs of kidney damage; 8 without). Fourteen individuals (43.75%) had CKD stage II (6 with signs of kidney damage; 8 without). The new Schwartz equation for CKD better estimated GFR in comparison to the Schwartz formula and the Filler formula. Furthermore, the WT survivors had signs of kidney damage despite the fact that GFR was not decreased below 90 ml/min/1.73 m(2) with 99 Tc- DTPA.

Nephrotoxicity of cancer treatment in children

Chronic renal impairment in children with cancer may be caused by the malignant process itself or result from adverse effects of treatment including cytotoxic drugs, radiotherapy, surgery or supportive treatment. Although severe renal chronic disease is uncommon, occurring in only 0.8% of long-term survivors of childhood cancer, 1.9% of all cases of established renal failure are due to malignancy and 0.8% to drug nephrotoxicity. The relative risk of severe renal chronic disease (compared with siblings) is 8.1, and that of renal failure or the need for dialysis is 8.9. The cytotoxic drugs most likely to cause important chronic nephrotoxicity are ifosfamide and cisplatin, both of which are used widely in many solid tumors and may cause chronic glomerular and/or renal tubular toxicity in 30–60% of treated children. Significant renal toxicity is less frequent with other chemotherapeutic drugs, but may result from treatment with carboplatin, methotrexate and nitrosoureas. Other cytotoxic drugs occasionally cause specific patterns of glomerular or tubular toxicity in children. Partial or unilateral nephrectomy leads to hypertrophy and hyperfiltration of the remaining renal tissue, and may result in microalbuminuria, hypertension and in rare cases, chronic renal impairment. Radiotherapy to a field including renal tissue may cause late onset chronic renal damage, manifest by hematuria, proteinuria, hypertension and anemia, sometimes progressing to chronic renal failure. Chronic nephrotoxicity is also common in survivors of hemopoietic stem cell transplantation, and is often multifactorial with contributions from prior chemotherapy, total body irradiation, immunosuppressive drugs and transplant complications, such as infection or hemorrhage. Patients at risk of renal damage should be monitored regularly with a defined surveillance protocol to enable timely management. General measures often employed to prevent or reduce nephrotoxicity include the use of intravenous hydration during drug administration and avoidance of known risk factors, such as high drug doses. Although numerous potentially nephroprotective drugs have been suggested and investigated, none have yet been introduced into clinical use in children due to the lack of proven efficacy. Improved understanding of the pathogenesis of nephrotoxicity is necessary to reduce the frequency and severity of this potentially serious complication of treatment in children with cancer.

Pregnancy outcome after treatment for Wilms tumor: a report from the national Wilms tumor long-term follow-up study

PURPOSE

This study was undertaken to evaluate the effect of prior treatment with radiation therapy or chemotherapy for unilateral Wilms tumor (WT) diagnosed during childhood on pregnancy complications, birth weight, and the frequency of congenital malformations in live-born offspring.

PATIENTS AND METHODS

We reviewed pregnancy outcomes among female survivors and partners of male survivors of WT treated on National Wilms Tumor Studies 1, 2, 3, and 4 by using a maternal questionnaire and a review of both maternal and offspring medical records.

RESULTS

We received reports of 1,021 pregnancies with duration of 20 weeks or longer, including 955 live-born singletons, for whom 700 sets of maternal and offspring medical records were reviewed. Rates of hypertension complicating pregnancy (International Classification of Diseases [ICD] code 642), early or threatened labor (ICD-644) and malposition of the fetus (ICD-652) increased with increasing radiation dose in female patients. The percentages of offspring weighing less than 2,500 g at birth and of those having less than 37 weeks of gestation also increased with dose. There was no significant trend with radiation dose in the number of congenital anomalies recorded in offspring of female patients.

CONCLUSION

Women who receive flank radiation therapy as part of the treatment for unilateral WT are at increased risk of hypertension complicating pregnancy, fetal malposition, and premature labor. The offspring of these women are at risk for low birth weight and premature (ie, < 37 weeks gestation) birth. These risks must be considered in the obstetrical management of female survivors of WT.

Cystatin C and parenchymal thickness/kidney length ratio in Wilms tumor survivors

BACKGROUND

This study presents a clinical, biochemical, and sonographic evaluation of single kidneys in Wilms tumor survivors.

PROCEDURE

The function of single kidneys in 26 Wilms tumor survivors (mean age, 11.17 years; mean follow-up, 7.09 years) was evaluated using cystatin C (CysC) levels and compared to serum creatinine concentration and glomerular filtration rate (eGFR), the latter of which was estimated by the Schwartz formula. The length of the kidney, the resistance index (RI) of the renal vessels, and the parenchymal thickness/kidney length ratio (PT/KL) were evaluated by sonographic examination.

RESULTS

Group A (n = 15) consisted of children with normal CysC levels, and group B (n = 11) consisted of children with CysC over 0.95 mg/L. No differences were observed between the groups in creatinine concentration, age, follow-up evaluation, age at the time of diagnosis, or kidney size. Children with elevated CysC had statistically lower eGFR (P = 0.02) and PT/KL (P = 0.0065). The correlation rate between CysC and PT/KL in all children was -0.38. Kidney hypertrophy was observed in 23 children and was correlated with CysC (group A, R = 0.46; group B, R = 0.4; P < 0.05). RI was normal in all individuals.

CONCLUSIONS

CysC levels may be elevated in people with normal GFR. Hypertrophy of a single kidney increases with deteriorating kidney function. PT/KL should be verified in future studies as a sonographic marker of kidney impairment.

Renal late effects in patients treated for cancer in childhood: a report from the Children's Oncology Group

Improvements in childhood cancer therapy have led to increasing numbers of long-term survivors. These survivors are at risk for a variety of late effects due to the disease itself, treatment exposures (surgery, chemotherapy, and radiotherapy), underlying medical problems, and health behaviors. The COG LTFU Guidelines are risk-based, exposure-related recommendations for the identification and management of late effects due to therapies utilized in the treatment of childhood cancer, and are designed for asymptomatic survivors presenting for routine medical follow-up 2 or more years after completion of cancer therapy. The COG Guidelines Task Force on Urinary Tract Complications conducted an extensive review of the medical literature via MEDLINE. Specific treatment exposures which were reviewed include nephrectomy, chemotherapy regimens known to be nephrotoxic (cisplatin, carboplatin, ifosfamide, and methotrexate), and renal irradiation. Literature sources were ranked according to the strength of evidence and are cited in the review. This review summarizes the literature that supported the recommendations for cancer survivors at risk for nephrotoxicity previously outlined in the Children's Oncology Group Long-Term Follow-Up Guidelines for Survivors of Childhood, Adolescent and Young Adult Cancers (COG LTFU Guidelines).

Renal function after ifosfamide, carboplatin and etoposide (ICE) chemotherapy, nephrectomy and radiotherapy in children with Wilms tumour

We prospectively evaluated tumour response and renal function in 12 newly diagnosed children with high-risk Wilms tumour receiving ifosfamide, carboplatin and etoposide (ICE) chemotherapy. Two cycles of ICE were followed by 5 weeks of vincristine, dactinomycin and doxorubicin (Adriamycin) (VDA), and nephrectomy, radiotherapy, additional VDA, and a third ICE cycle. Carboplatin dosage was based on glomerular filtration rate (GFR) to achieve targeted systemic exposure (6mg/ml min). Mean GFR (measured by technetium 99m-DTPA clearance) declined by 7% after 2 cycles of ICE and by 38% after nephrectomy; the mean carboplatin dose was reduced 32% after nephrectomy. Mean GFR remained stable after the third ICE cycle. Although urinary beta(2)-microglobulin excretion increased during therapy, no patient had clinically significant renal tubular dysfunction at the end of treatment. Treatment with ICE, nephrectomy and radiotherapy significantly reduces GFR, largely as the result of nephrectomy. Adjustment of carboplatin dosage on the basis of GFR and careful monitoring of renal function may alleviate nephrotoxicity.

Disparities in renal endowment: causes and consequences

In humans, nephrogenesis is completed by 36 weeks of gestation. Thus, human kidney development is complete at the time of birth in full-term infants. Those infants born before 36 weeks of gestation are still undergoing nephrogenesis for several weeks after their preterm birth and, accordingly, may be exposed to medications that impact the kidney during its final stages of renal development. The ultimate nephron number (nephron endowment) may influence future response to kidney injury, should it occur. The concept that nephron number may strongly influence blood pressure as well as susceptibility to kidney disease in later life developed in parallel with that of perinatal programming, which holds that the perinatal milieu causes changes that permanently alter organ structure and function, preordaining adult physiology to some extent. Both concepts together may help elucidate, at least in part, the pathogenesis of not only primary but secondary hypertension. This article summarizes human data on nephron number and its evaluation and considers the circumstances, implication, and management of persons born with or acquiring a decreased complement of nephrons early in life. Insufficient data exist to predict outcome or guide management. However, a common-sense approach of avoiding nephrotoxins and minimizing renal stress is indicated.

Renal function adaptation in children with unilateral renal tumors treated with nephron sparing surgery or nephrectomy

PURPOSE

We studied the natural history of renal function following removal of different amounts of renal mass in a cohort of children with unilateral renal tumors.

MATERIALS AND METHODS

We compared kidney function and blood pressure before and after surgery in 26 patients with unilateral renal tumors treated with nephrectomy (group 1, 16 patients) or nephron sparing surgery (group 2, 10 patients). Serum creatinine and blood pressure measurements were indexed to age and sex, and expressed as standard deviation scores (SDSs). Values were means +/- SD.

RESULTS

Preoperatively, patients in group 1 had no significant differences with respect to serum creatinine SDS and blood pressure SDS compared to patients in group 2. At a mean cross-sectional followup of 72 and 65 months, respectively, patients in group 1 had higher serum creatinine SDS compared to those in group 2 (1.27 +/- 0.69 vs 0.70 +/- 0.49, p = 0.02), as well as higher systolic blood pressure SDS (0.72 +/- 0.74 vs -0.10 +/- 0.92, p = 0.01) and higher diastolic blood pressure SDS (0.87 +/- 0.77 vs 0.19 +/- 0.62, p = 0.01). Serum creatinine SDS and systolic blood pressure SDS had a significant positive correlation (r = 0.44, p = 0.02). A postoperative longitudinal study of all patients showed a progressive increase in serum creatinine SDS with increasing followup time (r 0.49, p = 0.02). The slope of regression line was sustained by a steep increase of serum creatinine SDS in 5 patients in group 1 and 2 patients in group 2.

CONCLUSIONS

In children with unilateral renal tumors nephron sparing surgery minimizes the decrease in renal function following renal ablative surgery, and may be of benefit in children with a progressive renal function decrease, probably due to a congenitally reduced nephron complement.

The congenital and acquired solitary kidney

The embryonic insult that results in unilateral renal agenesis may involve not only the ureteral bud but also other mesonephric duct derivatives, including the seminal vesicles, vas deferens, and epididymis; in the female with a solitary kidney, müllerian duct anomalies frequently occur. Normal renal development depends upon a normal ureteral bud, which undergoes orderly branching and penetrates the metanephric blastema at about the fifth week of gestation. Ureteral and kidney development are thought to be interdependent, and when there is failure of the ureteral bud to form or absence of the nephrogenic ridge, the kidney does not develop normally. Unilateral renal agenesis is compatible with normal longevity and does not predispose the contralateral kidney to greater-than-normal risk; nevertheless, patients should have annual surveillance, including a blood pressure measurement, serum creatinine if not initially normal, and urinalysis to detect proteinuria. Removal of one kidney leads to structural and functional changes by the remaining kidney, including increased filtration of the remaining glomeruli. These functional changes have generally been considered beneficial because they mitigate the reduction in the total glomerular filtration rate that would otherwise occur, but experimental evidence suggests that these changes may have an adverse effect on the remaining kidney. Clinical evidence shows that these changes do not lead to renal deterioration in kidney donors because the renal function of kidney donors is well preserved in over 20 years of follow-up after donor nephrectomy.

Nephrotoxicity in survivors of Wilms' tumours in the North of England

One aspect of concern for survivors of Wilms' tumour has been the late outcome in terms of renal function. Previous studies have documented low glomerular filtration rate and high blood pressure in some patients. Furthermore, disorders in tubular function (especially urinary concentration defects) have been suggested but not confirmed in small studies. The aim of this study was to determine the prevalence and nature of subclinical and overt glomerular, proximal and distal renal tubular toxicity in a population based cohort of survivors of Wilms' tumour. Forty patients (24 female) with a median age of 4.3 years (3 months-11.8 years) at diagnosis were studied. Median follow-up was 8.8 (range 0.06-27.5) years. Glomerular filtration rate was measured by (51)Cr-EDTA plasma clearance, proximal tubular function by electrolyte fractional excretions, urine excretion of low molecular weight proteins (retinol-binding protein) and renal tubular enzymes (alanine aminopeptidase; N-acetylglucosaminidase) and distal tubular function by the osmolality of the first two urines of the day on 3 consecutive days. Renal size (ultrasound) and blood pressure were also measured. Mean (range) glomerular filtration rate was 100 (61-150) ml min(-1) 1.73 m(-2). Nine were below the reference range for healthy individuals with two kidneys. Most serum electrolyte concentrations (sodium, potassium, chloride, calcium, magnesium and phosphate) fell within the normal range for age, as did the fractional excretions. The values that fell outside the normal range were only marginally abnormal. Subclinical measures of tubular toxicity (retinal-binding protein, alanine aminopeptidase, N-acetylglucosaminidase) were abnormal in only four patients. Thirty-seven patients achieved maximal urine osmolalities > or =800 mOsm kg(-1), but three failed to achieve this value even after DDAVP administration. Two patients had evidence of increased urinary albumin excretion. Compensatory renal hypertrophy was seen in all but two patients, but blood pressure was within normal limits in all patients. Current and past treatment for Wilms' tumour does not have any clinically important nephrotoxic effect in the majority of patients. This finding will enable paediatric oncologists to reassure patients and parents that treatment for Wilms' tumour rarely causes long-term renal impairment.

The influence of dose per fraction on the pathogenesis of radiation nephropathy

Both kidneys of male Wistar rats were irradiated with either a 10-Gy single dose or 26 Gy at a rate of 2 Gy per fraction per day. Serum blood urea nitrogen (BUN), creatinine and blood haematocrit levels were assessed prior to radiotherapy and at intervals of 8 weeks thereafter. A subset of animals from each dose group were killed at 4, 8, 16 and 24 weeks and both kidneys of each animal were examined by electron microscopy. In both dose groups a significant increase in BUN and creatinine levels, together with a decrease in haematocrit level, was observed at 16 weeks, and this was followed by an apparent improvement at 24 weeks. There was no statistical difference in these responses between the two groups. The morphological changes in both dose groups were essentially similar, but differed in severity. At 4 weeks after irradiation glomerular and proximal tubular injury were observed in both groups. A marked increase of glomerular and tubular injury in the 10-Gy dose group, without any apparent progression in the 26-Gy dose group, was detected at 8 weeks. By 16 weeks a noticeable improvement in both tubular and glomerular lesions (especially in the 10-Gy dose group) was observed. No apparent difference from the 16th week of evaluation was found at 24 weeks. These findings indicate that there is some recovery in kidney after irradiation, but the extent of the recovery process is somewhat limited.

Conservative surgical management of bilateral Wilms tumor: results of the United Kingdom Children's Cancer Study Group

PURPOSE

Bilateral Wilms tumor presents the clinician with a treatment dilemma. Since 1980 most centers of the United Kingdom Children's Cancer Study Group have used a conservative surgical approach with initial biopsy followed by chemotherapy and delayed surgical resection. We assess the outcome of this treatment approach in terms of survival, and preservation of renal mass and function.

MATERIALS AND METHODS

We retrospectively analyzed the records of 71 children with bilateral Wilms tumor diagnosed between 1980 to 1995 at 17 United Kingdom Children's Cancer Study Group centers. In 57 patients conservative surgical treatment with initial biopsy was followed by chemotherapy and delayed tumor resection, while 13 underwent initial surgical resection followed by chemotherapy. One patient was excluded from study because the lesion in 1 kidney proved to be a benign cyst. Mean followup was 6 years (range 1 to 15). The percentage of renal tissue involved with tumor and preserved was estimated, and renal function at the last followup was recorded.

RESULTS

Overall survival was 69% with similar survival in the conservatively treated and initial surgical resection groups. At the last followup renal function was normal in 80% of the patients in each group. Mean preserved renal mass was 45 and 35% in the conservatively treated and initial resection groups, respectively, with a trend toward better preservation in those treated conservatively. Bilateral Wilms tumor with an unfavorable histology was associated with a poor prognosis.

CONCLUSIONS

Conservative surgical treatment of favorable histology bilateral Wilms tumor may improve the preservation of renal mass and function without impairing patient survival.

Long-term renal function in patients with irradiated bilateral Wilms tumor. National Wilms' Tumor Study Group

The treatment of bilateral Wilms tumor (BWT) involves a multidisciplinary approach including surgery, chemotherapy, and radiation therapy. The long-term renal function in patients receiving all three treatment modalities has not been evaluated. Long-term renal function was evaluated in 81 children with synchronous BWT who received radiation therapy as part of their treatment. Renal function was assessed by measuring blood urea nitrogen (BUN) and serum creatinine (Cr). The normal range for the BUN was defined as 10-24 mg/dl, and the Cr was considered normal at levels of <1.5 mg/dl. Moderate elevations were defined as a BUN of 25-50 mg/dl and/or a Cr of 1.6-2.5 mg/dl and marked elevations as a BUN of >50 mg/dl and/or a Cr of >2.5 mg/dl. BUN and Cr levels were measured prior to treatment and at the following intervals: 6 months after treatment, 1 year after treatment, 2 years after treatment, and at last follow-up. Any elevation during the posttreatment follow-up period was considered abnormal. A total of 28 children (34.6%) had elevated BUN and/or Cr levels, and 18 had moderate and 10 had marked renal insufficiency. No dose-response relationship was established when comparing the radiation doses of those with elevated values to those with normal values. The renal complication rate was moderate, and other factors including surgery, extent and nature of chemotherapy, and recurrent tumor must also be taken into account. The elevations present in several children could be attributed to tumor recurrence and in one case to gentamicin toxicity. The management of children with BWT should consider all of these risks, and attempts to preserve renal parenchyma are warranted.

The effect of Wilms tumor chemotherapy on contralateral renal growth after nephrectomy

PURPOSE

Our aim was to evaluate the effect of current Wilms tumor chemotherapy on renal growth and function after unilateral nephrectomy.

MATERIALS AND METHODS

Yorkshire piglets were enrolled in 2 study groups: group 1--6 underwent unilateral nephrectomy and placebo infusion, and group 2--10 underwent nephrectomy, and infusion of 7.5 mcg/kg. actinomycin D and 0.75 mcg/m2 vincristine according to the National Wilms Tumor Study 4 protocol. Weekly measurements of renal size by ultrasound and gross specimens at sacrifice at age 11 weeks were examined and weekly laboratory studies were recorded. Growth rates of renal length and volume were evaluated by linear regression analysis. Terminal renal length and volume were compared between groups.

RESULTS

Mean slope plus or minus standard deviation of the rate of growth in length in the control and chemotherapy groups was 0.067 +/- 0.004 and 0.074 +/- 0.011, respectively (p < or = 0.148, not statistically significant). Mean slope of growth in volume was 1.401 +/- 0.240 versus 1.642 +/- 0.456 (p < or = 0.252), average terminal renal length was 10.71 +/- 1.02 versus 11.58 +/- 1.03 cm (p < or = 0.13, not significant) and mean final volume was 128.67 +/- 32.41 versus 137 +/- 32.52 cc (p < or = 0.65). No differences in final serum creatinine levels were noted.

CONCLUSIONS

Chemotherapy for Wilms tumor did not adversely affect contralateral renal growth or function in a nephrectomized piglet model.

[Renal function after nephrectomy for Wilms' tumor]

BACKGROUND

Most children with Wilms tumour recover after nephrectomy, chemotherapy and sometimes radiotherapy. It is therefore important to assess their long-term renal function.

POPULATION AND METHODS

Thirty-three patients with Wilms tumour experienced unilateral nephrectomy between 1986 and 1993: three were excluded; 23 were staged as grade I, one at grade II, two at grade III and four at grade IV. They were treated with SIOP 6 and SIOP 9 protocols. The results were compared to five controls who underwent unilateral nephrectomy including three for renal trauma. The glomerular filtration rate (GFR) was measured by inulin clearance and the renal plasma flow (RPF) by para-amino-hippuric acid clearance.

RESULTS

The mean age at nephrectomy was 3.4 +/- 2.5 years (median: 3, range: 0.2-10.6) and the duration of follow-up was 4.6 +/- 3.1 years (median: 4.5, range: 1-8.5), the GFR was 93 +/- 13 mL/min/1.73 m2 (median: 93, range: 73-130), the RPF was 441 +/- 85 mL/min/1.73 m2 (median: 453, range: 236-650) and the filtrated fraction (FF) was 0.21 +/- 0.03 (median: 0.20, range: 0.18-0.31). The difference in renal function between patients and controls was not significant (GRF: 86 +/- 12 mL/min/1.73 m2, RPF: 486 +/- 185 mL/min/1.73 m2, FF: 0.22 +/- 0.03). The electrolyte reabsorption rate was normal and none of the patients suffered from arterial hypertension. Fourteen children had urinary albumin: creatinine ratio > 2 g/mol. When comparing patients according to the duration of follow-up after nephrectomy (< 4 years vs > 4 years), the renal function was not statistically different. The age at nephrectomy (< 2 years vs > 2 years) did not increase the risk of renal impairment.

CONCLUSION

Children with Wilms tumour who were treated with nephrectomy and non-nephrotoxic drugs (actinomycin, vincristine, epiadriamycin) have a good long-term renal outcome. It is speculated that systematic renal investigation should be limited to those children with increased microalbuminuria and/or elevated blood pressure.

Renal salvage procedures in patients with synchronous bilateral Wilms' tumors: a report from the National Wilms' Tumor Study Group

Synchronous bilateral Wilms' tumor accounts for 4% to 6% of all Wilms' tumors. Renal salvage procedures (partial nephrectomy and enucleation) have been recommended to conserve renal parenchyma. The objective of this study was to review the results of renal salvage operations performed in children who had bilateral neoplasms. The authors reviewed the records of 98 children enrolled in the Fourth National Wilms' Tumor Study who had synchronous bilateral tumors and underwent renal salvage procedures. One hundred thirty-four kidneys were managed with renal salvage procedures. Complete excision of gross disease was accomplished in 118 (88%) of the 134 kidneys. Local tumor recurrence in the remnant kidney or tumor bed occurred in 11 cases (8.2%). Overall, 72% of the kidneys were preserved, and the 4-year survival rate was 81.7%. The surgical morbidity after a salvage procedure was comparable to that of a complete nephrectomy in patients with unilateral Wilms' tumor. Although the incidence of positive surgical margins is worrisome, it did not invariably lead to local recurrence in the remnant kidney or the tumor bed.

Renal function after unilateral nephrectomy for Wilms' tumour: the influence of radiation therapy

The effect of therapy on renal function after unilateral nephrectomy for Wilms' tumour was studied. In the second year following unilateral nephrectomy, glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were estimated simultaneously by measuring 125I-iothalamate clearance and 131I-hippurate clearance. Of 41 evaluable patients, 29 received chemotherapy as sole treatment modality following nephrectomy (group 1); 12 patients additionally received radiation therapy to a field that included the remaining kidney (group 2). Results were expressed as standard deviation scores (z-scores). In group 1, mean z-score for GFR was -0.27 (94.6% of normal) and in group 2 mean z-score was -1.51 (72.7% of normal for two kidneys) (P = 0.022, Mann-Whitney U-test). Mean z-score for ERPF was -0.09 (97.0%) in group 1 and -1.53 (73.8%) in group 2 (P = 0.039). It was concluded that the combination of chemotherapy and radiation therapy, in contrast to chemotherapy alone, negatively affects the ability of the remaining kidney to adjust its function after the loss of its counterpart.

Renal failure in Wilms' tumor patients: a report from the National Wilms' Tumor Study Group

This report defines the incidence and determines the etiology of renal failure (RF) in patients undergoing treatment for Wilms' tumor (WT). The database of the National Wilms' Tumor Study (NWTS) was searched to identify all children reported to have developed chronic renal failure. There were 55 patients found to have RF. Of these, 39 patients had bilateral tumors, 15 with unilateral disease and one with a WT in a solitary kidney. The median interval from diagnosis to the onset of renal failure was 21 months. The incidence of RF in bilateral WT was 16.4% for NWTS-1 & -2, 9.9% for NWTS-3, and 3.8% for NWTS-4. The incidence of RF in unilateral WT remained stable. The most common etiologies of RF were: bilateral nephrectomy for persistent or recurrent tumor (24 pts), Drash syndrome (12 pts), progressive tumor in the remaining kidney (5 pts), radiation nephritis (6 pts), and other causes (5 pts). The etiology of renal failure was not reported in three children. Children with unilateral WT and a normal contralateral kidney have a very low incidence of RF, and this review does not support a recommendation for parenchymal sparing procedures in these patients. Children with bilateral WT are at risk for the development of RF, and parenchymal sparing procedures are warranted.

Growth of the solitary kidney after nephrectomy in children with unilateral Wilms' tumor

OBJECTIVE

We reviewed the length of the solitary kidney from all ultrasound examinations in 34 children who had undergone unilateral nephrectomy for Wilms' tumor, in order to determine the frequency of renal hypertrophy in this population. Standard sonographic criteria for nephromegaly were used.

MATERIALS AND METHODS

We generated a z-score for each measurement of the renal length, using an interpolated computer model based on published standards for sonographic renal length in relation to age. A retrospective age- and gender-matched control population of children with sonographically normal paired kidneys was generated from a departmental computerized pediatric uroradiology data base, and their ipsilateral renal lengths were compared with those of the study patients. Sonographic renal hypertrophy (SRH) was defined by two or more consecutive measurements of the renal length exceeding two standard deviations longer than the mean for the patient's age, with no later normal measurement.

RESULTS

Seventeen (50 %) of the 34 patients developed SRH. The latest measurements of the solitary kidney in the patients were significantly longer (mean z = 2.210) than in their controls (mean z = 0.040), even among the patients who did not develop SRH (patients' mean z = 1.000, controls' mean z = -0. 210, p < 0.001). Because boys had slightly longer kidneys than girls (both patients and controls), SRH was also noted more often in boys. The frequency of SRH was unrelated to age at nephrectomy, side of the solitary kidney, tumor stage, chemotherapy regimen, or treatment with radiation therapy.

CONCLUSIONS

Although renal growth in a solitary kidney is accelerated in most children after unilateral nephrectomy for Wilms' tumor, the sonographic length of the solitary kidney will be larger than normal in only half of the patients.

Damage to the urinary tract secondary to irradiation

During the past two decades highly effective multimodality therapy with surgery, chemotherapy and irradiation has been developed through consecutive national and international study protocols for childhood genitourinary cancers, the model being Wilms' tumor. These studies represent a landmark achievement in the history of pediatric oncology and mark the success of multi-institutional efforts. Now that excellent survival rates have been established, current interest is now directed primarily at examination of survivors for long-term treatment complications and minimizing the side effects while preserving treatment efficacy. Treatment sequelae may not become evident until many years after the initial diagnosis of cancer and may have adverse influences on long-term survival and/or the quality of life of former patients. With radiotherapy being a mainstay on the stage adjusted therapy of primarily Wilms' tumor and rhabdomyosarcoma, morbidity may occur as either acute or chronic with the genitourinary tract as an important adversely affected vital organ system. The effects of radiotherapy in the treatment of genitourinary childhood cancers on the urinary tract are reviewed here.