Renal function in long-term survivors after treatment for nephroblastoma

Kidney injury rates after unilateral nephrectomy in childhood-a systematic review and meta-analysis

BACKGROUND

Unilateral nephrectomy is a relatively common procedure in children which results in a solitary functioning kidney (SFK). Living with an SFK predisposes to kidney injury, but it remains unknown which children are most at risk. We aimed to investigate kidney injury rates in patients who underwent unilateral nephrectomy in childhood and to investigate differences among nephrectomies performed for a congenital anomaly, malignancy or other condition.

METHODS

MEDLINE and EMBASE were searched for studies reporting kidney injury rates [i.e. proteinuria, hypertension and/or a decreased glomerular filtration rate (GFR)] of patients who underwent unilateral nephrectomy during childhood. Studies including five or more patients with at least 12 months of follow-up were eligible. Analyses were performed using random effects models and stratified by indication for nephrectomy. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines were used for reporting.

RESULTS

Over 5000 unique articles were screened, of which 53 studies reporting on >4000 patients were included in the analyses. Proteinuria, hypertension and a decreased GFR were present in 15.3, 14.5 and 11.9% of patients, respectively. Heterogeneity among the studies was large in several subgroups, impairing quantitative meta-analyses. However, none of our analyses indicated differences in injury rates between a congenital anomaly or malignancy as an indication for nephrectomy.

CONCLUSIONS

Unilateral nephrectomy during childhood results in signs of kidney injury in >10% of patients, with no clear difference between the indications for nephrectomy. Therefore, structured follow-up is necessary in all children who underwent nephrectomy, regardless of the indication.

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.

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.

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.

Influence of donor and recipient ages and sex on graft function after pediatric renal transplantation

BACKGROUND

Adult donor grafts adapt to the smaller size of the child recipient by reducing their absolute glomerular filtration rate (GFR) (ml/min). The question arises whether these grafts can increase the absolute GFR when the child recipient grows or whether a child donor graft can better increase its function. The aim of this study was to evaluate the influence of donor and recipient ages and sex on renal function.

METHODS

Eighty-five children and adolescents, aged 0.4-20.5 years at transplantation, were monitored annually, by GFR and effective renal plasma flow (ERPF), determined by clearances of inulin and para-aminohippuric acid. The patients received 90 grafts from donors aged 3-67 years. Follow-up time was around 5 years.

RESULTS

Absolute GFR and ERPF (ml/min) of grafts from donors <20 years of age (all cadaveric donor grafts) increased during follow-up, resulting in a constant relative GFR and ERPF (ml/min/1.73 m2), whereas absolute GFR and ERPF of grafts from donors >20 years of age remained constant during follow-up, resulting in a significant decrease in relative values. Relative GFR and ERPF fell during follow-up in young recipients (<12 years of age), but remained constant in older recipients (>12 years). Donor and recipient sex did not influence renal function.

CONCLUSIONS

Child donor grafts seem better able to increase their function with the growth of the child recipient than adult grafts. However, the limited access to pediatric grafts and the fact that pediatric cadaveric grafts might involve technical problems in connection with grafting restrict their use.

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 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.

Glomerular volume and renal function in children with different types of the nephrotic syndrome

Glomerular hypertrophy has been suggested to be an important factor in the pathogenesis of focal glomerular sclerosis. The aim of the present study was to analyse retrospectively the renal biopsies of 58 children (0.2-16.1 years of age) with different types of the nephrotic syndrome, minimal change nephrotic syndrome (MCNS), diffuse mesangial proliferation (DMP) and focal segmental glomerulosclerosis (FSGS). Glomerular surface area was measured and glomerular volume was calculated and related to steroid responsiveness and to renal function, measured by clearances of inulin and para-aminohippuric acid. Glomerular volume correlated with body surface area (BSA) and age. Because of this, patients with FSGS and DMP were matched according to BSA and age, with corresponding MCNS patients. Glomerular volumes of FSGS and DMP patients were significantly larger than those of MCNS patients. In the MCNS patients, significant correlations were found between glomerular volumes and glomerular filtration rate and effective renal plasma flow. Steroid-dependent and steroid-resistant patients showed larger glomeruli than the steroid-responsive children. We suggest that hyperfiltration and hyperperfusion, among other factors, may contribute to glomerular hypertrophy, mesangial proliferation and glomerulosclerosis.

Comparative evaluation of iohexol and inulin clearance for glomerular filtration rate determinations

We evaluated iohexol as a filtration marker in 150 children. The clearance of iohexol was compared with that of inulin or with a formula clearance. The single-sample clearance of iohexol showed a good correlation with the clearance of inulin (r = 0.834). The clearance of iohexol correlated well (r = 0.672) with the formula clearance. The optimal blood sampling time for iohexol clearance determinations appears to be between 120 and 180 min after injection, at least in patients with relatively normal filtration rates. We conclude that iohexol clearance is an accurate method of determining the glomerular filtration rate in clinical practice.

Renal size and function after cure of Wilms' tumour

Now that most patients with Wilms' tumour are cured, it is practicable to study the long-term morbidity of their treatment and use this information to reduce treatment sequelae in the future. In this study we evaluate the size and function of the remaining kidney in 53 survivors of Wilms' tumour with a mean off treatment follow-up of 13 years. There was evidence of renal dysfunction in 17 (32%), including ten (19%) with a low GFR (< 80 ml/min/1.73 m2SA), six (11%) with hypertension and five (9%) with increased urinary albumin excretion. Measurements of renal size showed 'good' renal compensatory hypertrophy in only 55% of patients. 'Good' refers to renal size of more than 2 s.d. above the mean renal length for children with two kidneys. There were no correlations between GFR, renal size, blood pressure, microalbuminuria or type of treatment. However, children less than 24 months at diagnosis and children receiving chemotherapy with radiation doses to remaining kidney of more than 1200 cGy had a worse renal prognosis. Patients whose Wilms' tumour is diagnosed in infancy should have careful long-term follow-up of renal function and size. Older patients may safely be followed up less often, unless their remaining kidney was received > 1200 cGy.

Long-term followup of renal morphology and function in children with recurrent pyelonephritis

Renal morphology and function were evaluated in 161 children with recurrent pyelonephritis with or without vesicoureteral reflux and with or without scarred or small kidneys. The patients were followed for 1 to 21 years. Renal function was determined by glomerular filtration rate and effective renal plasma flow by clearances of inulin and paraaminohippuric acid. Of 105 children with normal kidneys originally small or scarred kidneys developed in 37, of whom 22 had grade III or greater vesicoureteral reflux, while small kidneys developed in 13 of 29 children with renal scarring originally. Of the 37 children with normal kidneys originally renal parenchymal scarring developed in 14 after the age of 4 to 5 years. Glomerular filtration rate was already < -2 standard deviations of that of controls in 51% of the patients at the first and in 53% at the last investigation of renal function. Of these patients with a glomerular filtration rate of < -2 standard deviations 69% had small or parenchymally reduced kidneys most of whom had the first pyelonephritis episode before age 3 years. Patients with small kidneys had a lower glomerular filtration rate than those with normal sized kidneys, whether scarred or not. The low glomerular filtration rate and its subsequent further reduction were related to kidney size and not to the presence or degree of vesicoureteral reflux. However, in individual patients the rate of functional deterioration could not be predicted from the radiological findings. Patients with bilateral small kidneys seemed to show the greatest decrease in glomerular filtration rate during followup as did those with grade III or greater reflux undergoing surgery bilaterally and those patients also had a lower glomerular filtration rate at the last investigation compared to patients not undergoing surgery. In conclusion, renal functional damage seems to occur early in the course of the disease and seems to be related to kidney size but there is a further slow progression with reduction in renal function which occurs, although this is difficult to predict from the radiological changes in individual patients. Therefore, patients with recurrent pyelonephritis should be followed regularly by glomerular filtration rate determination using an accurate method.

Renal function following kidney transplantation in children treated with cyclosporine

The study was performed to evaluate the long-term renal function of children treated with cyclosporine after kidney transplantation. Renal function was determined with clearances of inulin and aminohippurate sodium for evaluating glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Thirty-six children aged 0.4-16.2 (median 6.9) years at transplantation were examined within 5 months of transplantation and then yearly over 0.3-7.1 years. Twenty-five children and young adults, 1.5-20 (median 7.7) years of age, with solitary kidneys because of renal agenesis or nephrectomy, served as controls. The GFR and ERPF within 1 year of transplantation were significantly lower than those of controls (65 +/- 19 and 345 +/- 88 vs 96 +/- 12 and 474 +/- 91 ml/min per 1.73 m2, respectively). GFR remained constant 4 years after transplantation, but ERPF decreased significantly. Significant inverse correlations were found between GFR within 5 months of transplantation and the mean cyclosporine concentration and the number of rejection episodes. The frequency of hypertension decreased from 82% within 5 months of transplantation to 0% after 4 years. The absolute GFR increased during follow-up. In conclusion, kidney transplantation results in a reduced renal function compared with that of solitary native kidneys. The reduction in renal function correlated with the number of rejection episodes and the cyclosporine load. The increase in absolute GFR during follow-up suggests a remaining capacity for growth and/or compensatory hypertrophy.

A comparative study of size and function of the remnant kidney in patients nephrectomized in childhood for Wilms' tumor and hydronephrosis

To obtain more information about the natural history of compensatory renal hypertrophy beginning in childhood we traced those who were nephrectomized in childhood for Wilm's tumor (W) and hydronephrosis (Hn) between 1950 and 1978 at one department of surgery in Stockholm. All W patients had received treatment that suppresses cellular division. None of the patients were in renal failure or treated with antihypertensive drugs. All the patients in the follow-up study (22 W, 15 Hn) had a normal contralateral kidney at nephrectomy. Five healthy adults served as controls. The kidney was enlarged in both Hn (142%) and W (125%), but significantly larger in Hn than in W. Renal compensatory growth in W was retarded during the first two years after nephrectomy. The glomerular filtration rate (GFR) was 92% of control in Hn and 82% of control in W. The GFR did not seem to decline with a longer follow-up time in any of the groups. PAH clearance was the same in Hn and W. Albumin excretion was significantly higher in Hn than in W, but not significantly higher in W than in controls. The highest albumin excretion rates were found among the Hn patients with long follow-up time. The results suggest that the large increases in size and function that follow childhood nephrectomy can be blunted by antimitotic agents.

Hyperreninemic hypertension secondary to radiation nephritis in a child

Radiation injury to the kidney, first reported almost eighty years ago, may vary from subclinical changes in renal blood flow or enzyme activity to clinically significant hypertension and/or renal failure. A child with radiation-induced hyperreninemic hypertension was cured by nephrectomy. The microscopic, subclinical, and clinical changes of irradiation injury are reviewed. The etiology of radiation-induced hypertension, methods of radioprotection, and early detection of radiation renal damage are discussed.

Renoprival growth following treatment of unilateral Wilms' tumour

The renal growth pattern following uninephrectomy for Wilms' tumour was analysed in 18 boys and 18 girls by means of a comparison between renal parenchymal and body surface area. No straightforward correlation was noted between age at nephrectomy, chemo- and radiation therapy applied, and subsequent renoprival dimensions. Five years on average after operation, a mean renal size corresponding to approximately 125 per cent of the normal for one of two healthy kidneys was recorded. However, wide variations in size were observed, but only 10 patients had a compensatory growth of the remaining kidney equivalent to that seen in patients nephrectomized for unilateral, non-malignant renal disease.

Renal artery stenosis and hypertension after abdominal irradiation for Hodgkin disease. Successful treatment with nephrectomy

Hypertension secondary to stenosis of the left renal artery developed in a thirteen-year-old male six years after completion of inverted Y irradiation (3,600 rad) for abdominal Hodgkin disease. Surgical treatment with nephrectomy resulted in control of the hypertension without the use of antihypertensive agents. We review the literature for this unusual complication of abdominal irradiation, and recommend that a 99mTc-DMSA renal scan, selective renal vein sampling for renin determinations, and renal arteriography be performed on any patient in whom hypertension develops following abdominal irradiation in childhood.

Wilms' tumor--model of a curable pediatric malignant solid tumor

Wilms' tumor is the model of the treatment of a pediatric solid tumor. Initially it appeared that multi-modality therapy, consisting of transabodominal nephrectomy, post-operative radiation therapy to the tumor bed and adjuvant, single agent chemotherapy provided the highest likelihood of disease-free survival. The identification of important prognostic factors, such as histology, tumor weight, lymph node involvement and age at diagnosis has led to a re-examination of the treatment of Wilms' tumor. Future therapeutic developments will include the administration of less therapy to some well defined groups of patients, and the exploration of new programs for patients who have been demonstrated to have a poor prognosis using currently accepted treatment techniques.

Renal growth and function in patients nephrectomized in childhood

Eight patients nephrectomized in childhood were studied with regard to growth and function of the remaining kidney. The age of the patients ranged between 8 1/2 and 31 years and the follow-up period was from 1 to 20 years. In most of the patients, repeated renal size determinations were made on postoperative urograms. Normal values for kidney size in childhood are also presented. The structural hypertrophy continued for at least three years after nephrectomy and was most pronounced in patients nephrectomized before three years of age. When more than three years had passed after nephrectomy the remaining kidney was 35-65% larger than normal. Healthy young adults and children with a previous history of urinary tract infection served as controls for function studies. The balance between glomerular and tubular function was well preserved in nephrectomized patients. The renal surface area showed the same relation to GFR and to reabsorption of bicarbonate in nephrectomized patients as in controls. It is therefore concluded that the increase in kidney function following unilateral nephrectomy is, at least in early life, primarily due to structural enlargement.