Renal functional reserve in long-term survivors of unilateral Wilms tumor

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.

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.

Loss of a kidney during fetal life: long-term consequences and lessons learned

Epidemiological studies reveal that children born with a solitary functioning kidney (SFK) have a greater predisposition to develop renal insufficiency and hypertension in early adulthood. A congenital SFK is present in patients with unilateral renal agenesis or unilateral multicystic kidney dysplasia, leading to both structural and functional adaptations in the remaining kidney, which act to mitigate the reductions in glomerular filtration rate and sodium excretion that would otherwise ensue. To understand the mechanisms underlying the early development of renal insufficiency in children born with a SFK, we established a model of fetal uninephrectomy (uni-x) in sheep, a species that similar to humans complete nephrogenesis before birth. This model results in a 30% reduction in nephron number rather than 50%, due to compensatory nephrogenesis in the remaining kidney. Similar to children with a congenital SFK, uni-x sheep demonstrate a progressive increase in arterial pressure and a loss of renal function with aging. This review summarizes the compensatory changes in renal hemodynamics and tubular sodium handling that drive impairments in renal function and highlights the existence of sex differences in the functional adaptations following the loss of a kidney during fetal life.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Blunted sodium excretion in response to a saline load in 5 year old female sheep following fetal uninephrectomy

Previously, we have shown that fetal uninephrectomy (uni-x) causes hypertension in female sheep by 2 years of age. Whilst the hypertension was not exacerbated by 5 years of age, these uni-x sheep had greater reductions in renal blood flow (RBF). To further explore these early indications of a decline in renal function, we investigated the renal response to a saline load (25 ml/kg/40 min) in 5-year old female uni-x and sham sheep. Basal mean arterial pressure was ∼15 mmHg greater (P(Group)<0.001), and sodium excretion (∼50%), glomerular filtration rate (∼30%, GFR) and RBF (∼40%) were all significantly lower (P(Group)<0.01) in uni-x compared to sham animals. In response to saline loading, sodium excretion increased significantly in both groups (P(Time)<0.001), however this response was blunted in uni-x sheep (P(GroupxTime)<0.01). This was accompanied with an attenuated increase in GFR and fractional sodium excretion (both P(GroupxTime)<0.05), and reduced activation of the renin-angiotensin system (both P<0.05), as compared to the sham group. The reduction in sodium excretion was associated with up-regulations in the renal gene expression of NHE3 and Na(+)/K(+) ATPase α and β subunits in the kidney cortex of the uni-x compared to the sham animals (P<0.05). Notably, neither group completely excreted the saline load within the recovery period, but the uni-x retained a higher percentage of the total volume (uni-x: 48±7%; sham: 22±9%, P<0.05). In conclusion, a reduced ability to efficiently regulate extracellular fluid homeostasis is evident in female sheep at 5 years of age, which was exacerbated in animals born with a congenital nephron deficit. Whilst there was no overt exacerbation of hypertension and renal insufficiency with age in the uni-x sheep, these animals may be more vulnerable to secondary renal insults.

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.

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.

Survivorship: childhood cancer survivors

Late effects of therapy for childhood cancer are frequent and serious. Fortunately, many late effects are also modifiable. Proactive and anticipatory risk-based care can reduce the frequency and severity of treatment-related morbidity. The primary care clinician should be an integral component in risk-based care of survivors. Continued communication between the "late effects" staff at the cancer center and the primary care clinician is essential for optimum care of this high-risk population.

Hypertension and prehypertension in long-term survivors of childhood and adolescent cancer

BACKGROUND

Hypertension as a late effect following childhood and adolescent cancer has received little attention. Since obesity, a known risk factor for hypertension, is increased following some childhood cancers, it seems likely that significant numbers of survivors would have hypertension.

PROCEDURES

The records of patients seen in the Long Term Follow Up Clinic of Children's National Medical Center were examined for a single institution, retrospective study of blood pressure in survivors of childhood and adolescent cancer. Of 103 consecutive survivors who attended the clinic from January 1 through June 30, 2004, 51 (49.5%) were female and 52 (50.5%) were male. Their mean age was 14.6 years. Systolic and diastolic blood pressures for children and adolescents under 18 years of age were evaluated for hypertension and prehypertensive according to standards for age, sex, and height. Blood pressures for adults 18 years of age and older were evaluated according to standard adult values. Children and adolescents were evaluated for obesity and overweight according to body mass index (BMI) standards for age and sex. Adults were evaluated according to standard adult values.

RESULTS

Twenty-nine patients (28.2%) were hypertensive or prehypertensive, and 74 (71.8%) were normal. Thirty-eight patients (36.9%) were obese or overweight, and 65 (63.1%) were non-obese. Most Wilms tumor patients, 7 of 10 (70.0%), had hypertension or prehypertension, but only 4 of 10 (40.0%) were obese or overweight.

CONCLUSION

Careful follow-up of their blood pressure status is warranted for long-term survivors of childhood and adolescent cancer, especially for those with an initial diagnosis of Wilms tumor.

At what level of unilateral renal impairment does contralateral functional compensation occur?

Functional compensation occurs in a kidney when the function of the contralateral kidney is decreased or absent. What is, however, not documented is the level of unilateral renal impairment at which functional compensation occurs. Split function, as obtained from a radionuclide renogram, can only show the asymmetry between both kidneys. The aim of the present work was to evaluate at what level of unilateral impairment a functional compensation can be observed in the contralateral normal kidney. From a large database, 180 children over 2 years of age with unilateral pathology were retrospectively selected. All of them underwent a radionuclide study, combining a technetium-99m mercaptoacetyltriglycine (Tc-99m MAG3) renogram associated with a chromium-51 ethylenediaminetetraacetic acid (Cr-51 EDTA) overall clearance, allowing a precise estimation of single-kidney glomerular filtration rate (SKGFR). Below 30-35 ml/min/1.73 m2, there was a significant inverse correlation between SKGFR on the normal and the abnormal side. Above this level, no such correlation was observed, the mean SKGFR on the normal side remaining around 58 ml/min/1.73 m2, whatever the value of SKGFR on the abnormal side. In pediatric patients, hyperfunction occurs when SKGFR of the diseased kidney is below 30-35 ml/min/1.73 m2.

Follow-up after unilateral nephrectomy in children: is an estimate of glomerular filtration rate necessary?

OBJECTIVE

To determine the need for an estimate of glomerular filtration rate (GFR) in the follow-up of children undergoing unilateral nephrectomy for benign renal disease.

PATIENTS AND METHODS

Forty-four children (21 girls and 23 boys) undergoing unilateral nephrectomy for benign renal disease over a 3-year period were reviewed for the underlying diagnosis and indication for nephrectomy, imaging before and after surgery, postoperative GFR and final outcome. The follow-up included ultrasonography (US) of the contralateral kidney at 3 and 12 months and an estimate of GFR before discharge at > or = 1 year. All children were aged > 2 years when the GFR was measured. The criteria for discharge were normal imaging of the contralateral kidney before and after surgery and a normal GFR afterward. Spearman's correlation coefficient was used to determine the relationship between age, GFR and contralateral renal length after surgery.

RESULTS

The median (range) age at surgery was 2.5 (0.67-16) years. The indications for nephrectomy included reflux nephropathy in 18, multicystic dysplastic kidney in 12, a congenital obstructive uropathy in eight, congenital renal dysplasia in four and miscellaneous in two. All patients had a normal contralateral kidney before surgery on US and functional imaging, and normal US at the follow-up, with evidence of compensatory hypertrophy in all. The median (range) corrected GFR for the 44 children was 109 (81-140) mL/min/1.73 m2, with no correlation between age and GFR, or between renal length and GFR.

CONCLUSION

After unilateral nephrectomy for benign renal disease, provided there is a structurally and functionally normal contralateral kidney before surgery, with no abnormality on US, a routine estimate of GFR is unnecessary before discharge from follow-up. There was no correlation between GFR and age or renal length.

Partial nephrectomy for unilateral Wilms tumor: results of study SIOP 93-01/GPOH

PURPOSE

We evaluate results and long-term outcome after partial nephrectomy (PN) for unilateral Wilms tumor (ulWT) in relation to different histological features, performed as initial surgery or after induction chemotherapy (ChT).

MATERIALS AND METHODS

Data from patients with ulWT who had undergone PN in the German Study SIOP 93-01/GPOH were analyzed for time of surgery in the treatment schedule, postoperative stage, histological features, surgical radicality and outcome. The results were correlated with overall survival and relapse-free survival, and compared with those of patients who had undergone total tumor nephrectomy (TN).

RESULTS

A total of 770 patients underwent TN and 37 underwent PN, of which 766 (99.5%) and 36 (97.3%), respectively, were radical procedures. A total of 139 TNs and 15 PNs were performed at primary surgery, 630 TNs and 22 PNs after ChT, and 1 TN after irradiation. Two of 15 patients following primary PN and 1 of 22 following delayed PN had local recurrence. Two patients died of metastatic disease. Tumor stage, overall survival of 93% and relapse-free survival of 88% were equal after PN and TN in analysis of the whole group. This was also true for patients with surgery after ChT. One of 2 patients with histologically unfavorable disease had relapse after PN compared to only 3 of 35 patients with histologically low or intermediate risk disease.

CONCLUSIONS

PN should be performed only for small, histologically low or intermediate risk tumors after good response to ChT to secure a complete resection.

Kidney development and the fetal programming of adult disease

Recent evidence, from both epidemiological and animal experimental studies, suggest that the very first environment, the intrauterine, is extremely important in determining the future health of the individual. Genetic and 'lifestyle' factors impinge on, and can exacerbate, a 'programming' effect of an adverse fetal environment. In this review, we present compelling evidence to suggest that one of the major organs affected by an unfavourable prenatal environment is the kidney. Many of the factors that can affect fetal renal development (i.e. exposure to excess glucocorticoids, insufficient vitamin A, protein/calorie malnutrition (in rats) and alterations in the intrarenal renin angiotensinogen system), also produce hypertension in the adult animal. When nephron number is compromised during kidney development, maladaptive functional changes occur and can lead, eventually, to hypertension and/or renal disease. Surprisingly, it is during the very earliest stages of kidney development that the vulnerability to these effects occurs.

The long-term complications of chemotherapy in childhood genitourinary tumors

Combination chemotherapy, often in conjunction with surgery and external radiotherapy, is utilized in most children with tumors of the genitourinary tract. These chemotherapeutic agents are capable of causing a variety of delayed toxicities. Common late complications include cardiotoxicity associated with prior exposure to an anthracycline, pulmonary dysfunction, infertility in males due to prior therapy with alkylating agents, and secondary leukemia in individuals treated with epipodophyllotoxins.

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.

[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.

Renal function following unilateral nephrectomy for neuroblastoma and Wilms' tumour

To estimate the side effects of chemotherapy and the influence of age at the time of nephrectomy on renal function, we investigated renal function in 34 uninephrectomised children with neuroblastoma (NB) or Wilms' tumour (WT). The results were compared with 6 controls who underwent nephrectomy for non-malignant disease. Study of renal function was primarily based on the clearance of inulin and para-aminohippuric acid (Cin and CPAH, ml/min per 1.73 m2). No significant differences in Cin/CPAH (mean +/- SD) were found between the NB group (90 +/- 24/421 +/- 95), WT group (85 +/- 17/386 +/- 104) and the controls (93 +/- 13/430 +/- 61). Children with NB and WT were divided into two subgroups according to the theoretical nephrotoxic risk. There was no significant difference in renal function between NB or between WT subgroups. Cumulative cisplatin doses in children with NB did not affect renal function significantly. The age at time of unilateral nephrectomy (< or = 2 years vs. > 2 years) was not associated with a higher risk of renal damage in WT children, whereas in NB children the filtration fraction (Cin:CPAH) was higher in younger children (mean +/- SD: 0.243 +/- 0.023 vs. 0.191 +/- 0.041). In conclusion, uninephrectomised children with NB are supposed to have a higher risk of drug-induced renal impairment compared with those with WT. Our data do not confirm this hypothesis, since renal function was comparable to controls in both groups, except in younger patients with NB who show a high filtration fraction. Since the survival of children with NB has improved, a longer follow-up of their renal function in needed.

Long-term effects of reduced renal mass in humans

The long-term risks of kidney donation have not been well defined. We carried out meta-analysis of investigations that examined the long-term effects of reduced renal mass in humans. We used multiple linear regression to combine studies and adjust for differences in the duration of follow-up, the reason for reduced renal mass, the type of controls, age and gender. We analyzed 48 studies with 3124 patients and 1703 controls. Unilateral nephrectomy caused a decrement in glomerular filtration rate (-17.1 ml/min; 95% confidence interval -20.2 to -14.0 ml/min) that tended to improve with each 10 years of follow-up (1.4 ml/min/decade; 0.3 to 2.4 ml/min/decade). Patients with single kidneys had small, progressive increases in proteinuria (76 mg/day/decade; 52 to 101 mg/day/decade), but proteinuria was negligible after nephrectomy for trauma or kidney donation. Nephrectomy did not affect the prevalence of hypertension, but there was a small increase in systolic blood pressure (2.4 mm Hg; -0.3 to 5.1 mm Hg, P > 0.05) which rose further with duration of follow-up (1.1 mm Hg/decade; 0.0 to 2.2 mm Hg/decade). Diastolic blood pressure was higher after nephrectomy (3.1 mm Hg; 1.8 to 4.4 mm Hg), but this increment did not change with duration of follow-up. Thus, in normal individuals, unilateral nephrectomy does not cause progressive renal dysfunction, but may be associated with a small increase in blood pressure.

Bilateral Wilms tumor. Review of outcome, associated abnormalities, and late effects in 36 pediatric patients treated at a single institution

BACKGROUND

Patients with bilateral Wilms tumor have an increased incidence of associated abnormalities and nephrogenic rests and require individualized multimodality therapy for cure. The authors reported the associated abnormalities, outcome, complications, and late effects of treatment in a group of children with bilateral Wilms tumor treated at St. Jude Children's Research Hospital, Memphis, Tennessee, over a 28-year period.

METHODS

The records of 36 consecutive pediatric patients diagnosed with bilateral Wilms tumor between 1962-1990 were analyzed. Biopsy material was also reviewed, with particular emphasis on characterization of nephrogenic rests and histology.

RESULTS

Twenty-nine patients had synchronous tumors and 7 had metachronous lesions. Associated physical abnormalities were present in 12 patients and involved the genitourinary, cardiovascular, integumentary, and musculoskeletal systems. The overall survival for patients with metachronous tumors (71%) was similar to that for those with synchronous tumors (70%). There was no effect of age or the presence of nephroblastomatosis. Two patients with synchronous tumors initially treated with nephrectomy eventually required bilateral nephrectomies for contralateral recurrence after chemotherapy and radiation therapy. Nephrogenic rests were present in 22 of 30 evaluable patients. Two of three patients with metachronous tumors had intralobar nephrogenic rests. Bilateral renal salvage procedures were demonstrated to be technically feasible and effective in controlling disease without compromising renal function or survival. Late effects included scoliosis in three patients treated before 1970, cardiomyopathy in one patient who received 300 mg/m2 doxorubicin and 12 Gy pulmonary irradiation, and benign tumors in two patients, one of whom also had a bowel obstruction. Serum creatinine, urea nitrogen, and blood pressure were normal in 23 of 26 survivors.

CONCLUSIONS

The authors' experience supports a favorable outcome with minimal late effects for patients with bilateral Wilms tumor who receive individualized therapy at pediatric oncology centers.

Effects of treatment for childhood cancer on vital organ systems

Advances in treatment have dramatically increased the survival rate of children and adolescents with cancer. These treatments, however, may be associated with damage to vital organ systems, which may not be evident until many years after the initial diagnosis of cancer and may adversely affect long-term survival and/or the quality of life of former patients. The effects of treatment on three specific organ systems, heart, lungs, and kidneys, are reviewed here.

Urinary protein/creatinine index in follow up of patients with Wilms' tumour after nephrectomy

The protein/creatinine index (p/c) was determined in early morning urine (EMU) samples from available patients with Wilms' tumour who had had a nephrectomy and whose diagnosis had been made between January 1970 and December 1989. Clinical details were obtained by case note review. Results were obtained from 36 boys and 40 girls. The mean interval between nephrectomy and measurement of the EMUp/c was 9.0 years (2-23). Eleven patients had a EMUp/c greater than 20 mg/mmol (normal range less than 20). Of the 11 patients with proteinuria, there were in addition to nephrectomy other adverse features including bilateral tumours, treatment with nephrotoxic drugs, and dysplastic kidneys. Renal dysfunction seems most likely to occur where there are adverse factors in addition to unilateral nephrectomy. There was a significant correlation between the glomerular filtration rate and the EMUp/c, and it is thought that this is a simple tool which can be used for the regular monitoring of renal function in these patients.