Conservative management of hyperplastic and multicentric nephroblastomatosis

Unwrapping Nephrogenic Rests and Nephroblastomatosis for Pediatric Surgeons: A Systematic Review Utilizing the PICO Model by the APSA Cancer Committee

BACKGROUND

Nephrogenic rests (NR) may represent precursor lesions for Wilms tumor (WT), but their clinical course is not fully understood and no guidelines for treatment exist. This study sought to evaluate the outcomes of pediatric patients with NRs related to traditional chemotherapy and surgery.

METHODS

A PRISMA-P-compliant literature search was conducted in MEDLINE, Embase, CINAHL, Web of Science, COCHRANE, and SCOPUS from inception to June 2021. Clinical questions regarding the treatment of NRs, including chemotherapy and surgery, were developed in the population, intervention, comparison, and outcome format.

RESULTS

Twenty-five studies including 1445 patients met inclusion criteria for evaluating chemotherapy compared to observation for NRs. Eighteen studies including 1392 patients met inclusion criteria for evaluating the role of surgery for NRs. Patients with isolated NRs who underwent observation progressed to WT 33% of the time; chemotherapy reduced the rate of WT to 3.9%. Observation of multiple NRs and diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) led to progression to WT 50% and 100% of the time, respectively. Chemotherapy reduced the rate of WT to 34% for multiple NRs and 46% for DHPLN. Surgery for isolated NRs reduced the risk of WT development from 23.7% in patients with incomplete excision to 3.3% with complete excision; however, 96% of patients with incompletely excised NRs had bilateral disease.

CONCLUSIONS

Observation with close surveillance for isolated NRs is safe. Treatment with chemotherapy is recommended for patients with multiple NRs and DHPLN. Surgical management of NRs should focus on renal function preservation.

LEVEL OF EVIDENCE

Treatment study, Level III.

How does Nephroblastomatosis impact the prognosis of unilateral Wilms tumor?

PURPOSE

We aimed to explore whether Nephroblastomatosis (Nbm) has an effect on the prognosis of Wilms tumor (WT), and compare the relapse-free survival (RFS) and overall survival (OS) after surgery of WT patients with or without Nbm.

METHODS

We retrospectively analyzed the clinical data of children with WT admitted to our department from April 2010 to September 2021. The enrolled patients were divided into two groups according to whether they were combined with Nbm histologically or not, the Nbm group for patients accompany with Nbm and the non-Nbm group for pure WT. All patients underwent a standardized comprehensive treatment according to National Wilms Tumor Study 5. Clinical variables, pathological results, and the prognosis were collected during follow-up.

RESULTS

A total of 345 patients were finally enrolled in this study, of which 299 patients in the non-Nbm group and 46 patients in the Nbm group. Univariate Cox analysis revealed that Nbm was not the risk factor of either OS or RFS. The difference of postoperative RFS (P = 0.66) and OS (P = 0.68) between two groups was not significant. Subgroup analysis revealed that the RFS and OS between the non-Nbm group and the Nbm group had no statistical difference under the condition of same stage (low grade and high grade), same histology (favorable histology and unfavorable histology), same surgical approach (nephrectomy and nephron-sparing surgery), with or without lymph node metastasis (P > 0.05).

CONCLUSION

Although Nbm had a strong correlation with the occurrence of WT, a combined Nbm did not increase the risk of metastasis and poor prognosis of WT. After complete surgical resection followed by standardized treatment, the long-term RFS and OS were not different from pure WT. IEC-C-006-A04-V.06 retrospectively registered.

Outcome of two patients with bilateral nephroblastomatosis/Wilms tumour treated with an add-on 13-cis retinoic acid therapy - Case report

Although the fate of nephrogenic rests varies, they are known to be precursors of Wilms tumour. Thus, nephrogenic rests require adequate treatment to prevent malignant transformation. We added 13-cis retinoic acid to the standard chemotherapy with vincristine and actinomycin-D in two patients with bilateral nephrogenic rests/nephroblastomatosis. Patient 1 also had a history of Wilms tumour. 46 (patient 1) and 81 (patient 2) months after end of treatment, both patients show stable conditions with no signs of relapse or progressive disease. Our observation supports further investigation of retinoic acid in patients with nephrogenic rests and nephroblastomatosis.

Perilobar nephroblastomatosis: natural history and management

Nephroblastomatosis (NB) has been considered as a precursor of Wilms tumor (WT). The natural history of NB seems to present significant variation as some lesions may regress spontaneously, while others may grow and expand or relapse and develop into WT later in childhood. Although, most investigators suggest adjutant chemotherapy, the effect and duration of treatment are not well established. Children with diffuse perilobar NB, Beckwith-Wiedemann syndrome, and hemihypertrophy seem to particularly benefit from treatment. We discuss our experience on two cases of NB and we review the literature for the management of this rare condition.

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.

Current management of Wilms' tumor in children

PURPOSE

Wilms' tumor is the most common renal tumor in children. Outcomes have improved dramatically over the past few decades, but important treatment questions remain. These include the role of molecular biologic markers in stratifying patients for therapy or targeting tumors for treatment. We present a summary of these advances and outline the current treatment of Wilm's tumor.

MATERIALS AND METHODS

The medical literature and results of all cooperative group studies reporting treatment of children with Wilms' tumor were reviewed.

RESULTS

Overall survival exceeds 90% for most patients with nephroblastoma. However, outcomes for patients with rhabdoid tumors and diffuse anaplasia remain poor. The role of renal sparing surgery in patients with bilateral tumors is clear, but for children with unilateral tumors it continues to be defined.

CONCLUSIONS

Current protocols conducted by pediatric oncology groups are beginning to incorporate biologic features to stratify patients for therapy. Treatment strategies continue to focus on limiting late effects of treatment while maintaining an excellent survival. New therapies are needed to treat the high-risk patients who continue to have high relapse and mortality rates.

Renal tumours of childhood: an update

The role of the pathologist has been fundamental in the progress of the treatment of paediatric renal tumours. There are different philosophies in the treatment of these tumours, and there have been many recent advances in the areas of chemotherapy, identification of new entities, prognostic histological criteria following treatment and molecular prognostic and diagnostic features. This review discusses the different approaches of the different treatment protocols from Europe and North America, and reviews staging criteria, prognostic criteria and also the different tumour entities.

Wilms tumour: prognostic factors, staging, therapy and late effects

Wilms tumour is the most common malignant renal tumour in children. Dramatic improvements in survival have occurred as the result of advances in anaesthetic and surgical management, irradiation and chemotherapy. Current therapies are based on trials and studies primarily conducted by large multi-institutional cooperatives including the Société Internationale d'Oncologie Pédiatrique (SIOP) and the Children's Oncology Group (COG). The primary goals are to treat patients according to well-defined risk groups in order to achieve the highest cure rates, to decrease the frequency and intensity of acute and late toxicity and to minimize the cost of therapy. The SIOP trials and studies largely focus on the issue of preoperative therapy, whereas the COG trials and studies start with primary surgery. This paper reviews prognostic factors and staging systems for Wilms tumour and its current treatment with surgery and chemotherapy. Surgery remains a crucial part of treatment for nephroblastoma, providing local primary tumour control and adequate staging and possibly controlling the metastatic spread and central vascular extension of the disease. Partial nephrectomy, when technically feasible, seems reasonable not only in those with bilateral disease but also in those with unilateral disease where the patient has urological disorders or syndromes predisposing to malignancy. Partial nephrectomy, however, is frequently not sufficient for an anaplastic variant of tumour. The late effects for Wilms tumour and its treatment are also reviewed. The treatment of Wilms tumour has been a success story, and currently in excess of 80% of children diagnosed with Wilms tumour can look forward to long-term survival, with less than 20% experiencing serious morbidity at 20 years from diagnosis. The late complications are a consequence of the type and intensity of treatment required, which in turn reflects the nature and extent of the original tumour. Continual international trial development and participation will improve matching of treatment needs with prognosis, reducing long-term complications in the majority. The advent of molecular markers of disease severity and improved functional imaging might help.

Nephron-sparing surgery in children with primary renal tumor: indications and results

Nephron-sparing surgery (NSS) is the treatment of choice for children with bilateral Wilms' tumor (WT), or with WT on a single kidney, or with WT and a disease of the contralateral kidney, or with benign kidney tumor. NSS is a reasonable alternative to nephrectomy in children at risk of metachronous WT, including children with genetic syndromes, children younger than 1 year of age, and children with hyperplastic nephroblastomatosis. The use of NSS in selected children with "low-risk" or stage I "intermediate-risk" WT and a normal contralateral kidney is still controversial. Available data suggest that, in children with WT, NSS does not impair the outcome and has a renal function advantage over nephrectomy.

Nephroblastic Neoplasms

Nephroblastoma, or Wilms tumor, is a malignant embryonal neoplasm that is derived from nephrogenic blastemal cells, with variable recapitulation of renal embryogenesis. The pathogenesis of nephroblastoma is complex and has been linked to alterations of several genomic loci, including WT1, WT2, FWT1, and FWT2. Generally, nephroblastoma is composed of variable proportions of blastema, epithelium, and stroma, each of which may exhibit a wide spectrum of morphologic variations. Distinguishing nephroblastoma with favorable histology from tumors that exhibit anaplasia is an integral component of histologic assessment because of its prognostic and therapeutic implications. Nephrogenic rests and a special variant of nephroblastoma, cystic partially differentiated nephroblastoma, also are discussed.

LONG-TERM OUTCOME OF NEPHRON SPARING SURGERY AND SIMPLE NEPHRECTOMY FOR UNILATERAL LOCALIZED WILMS TUMOR

PURPOSE

We retrospectively assessed survival and local recurrence rates in children with unilateral localized Wilms tumor (WT) treated with nephron sparing surgery (NSS) or simple nephrectomy with removal only of the perirenal fat adherent to the tumor surface.

MATERIALS AND METHODS

The records of 70 children with renal tumor, operated on by the same surgeon between January 1968 and December 2003, were reviewed. Of 64 children with WT 52 with localized nonanaplastic WT were enrolled. Treatment was administered according to International Society of Pediatric Oncology protocols 1 to 2001 in all patients but 7, who were operated on between 1968 and 1971. Patients were stratified as having stage I (27), stage II (23) or stage III (2) disease. Surgical treatment included 40 simple nephrectomies, 10 NSSs (only stage I cases ascertained by frozen section) and 2 radical nephrectomies. Mean patient age at operation was 39.5 months (range 1 to 126). Followup ranged from 27 to 431 months (mean 188.4).

RESULTS

Event-free survival rate in all localized stages was 88.5% (stage I 92.6%, stage II 87%, stage III 50%). Two infants with stage I disease died after surgery for reasons not related to malignancy. Only 1 patient with stage II lymph node negative WT had local relapse.

CONCLUSIONS

Our results are similar to those achieved by radical nephrectomy in previous studies. Leaving Gerota's fascia in situ does not seem to confer a higher risk of local recurrence in patients with low stage nonanaplastic WT. After NSS Gerota's fascia may be used to cover the defect and to maintain tissue plains, thus, facilitating reintervention if necessary.