Wilms tumor

Consider – postoperative chemotherapy

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Consider –

postoperative chemotherapy

Treatment recommended for SOME patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

COG very-low risk patients (<2 years of age, <550 g tumor weight, stage I, any loss of heterozygosity [LOH] status): observation alone and a trial-protocol directed approach to relapse (COG study #AREN0532) or vincristine and dactinomycin (EE-4A regimen) if not being treated on a study.[84][85]

COG low-risk patients (any age or tumor weight, stage I or II, but no LOH at 1p and 16q): EE-4A regimen.[84]

COG standard-risk patients (stage I tumors ≥550 g with LOH at 1p and 16q): vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[84][86]

See local specialist protocol for dosing guidelines.

Primary options

EE-4A regimen

vincristine

and

dactinomycin

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

favorable histology: stage II

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

favorable histology: stage III

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

COG low-risk patients (any age or tumor weight, stage I or II, but no loss of heterozygosity [LOH] at 1p and 16q): vincristine and dactinomycin (EE-4A regimen).[84]

COG standard-risk patients (any weight stage II tumors with LOH at 1p and 16q): vincristine, dactinomycin, and doxorubicin (DD-4A regimen).

See local specialist protocol for dosing guidelines.

Primary options

EE-4A regimen

vincristine

and

dactinomycin

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

COG standard-risk patients (stage III with no loss of heterozygosity [LOH] at 1p and 16q): vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[87]

COG high-risk patients (stage III with LOH at 1p and 16q): DD-4A regimen for 6 weeks, and then switched to regimen M (vincristine, dactinomycin, doxorubicin, cyclophosphamide, and etoposide).[84][86]

See local specialist protocol for dosing guidelines.

Primary options

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

Regimen M

vincristine

and

dactinomycin

and

doxorubicin

and

cyclophosphamide

and

etoposide

favorable histology: stage IV

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

All stage III tumors receive either flank irradiation or whole abdomen irradiation.[84][86]

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

COG standard-risk (stage IV with no loss of heterozygosity [LOH] at 1p and 16q): vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[83][84] Patients with pulmonary metastases with a complete response at week 6 continue receiving DD-4A regimen chemotherapy.[83] Patients with an incomplete/slow response of pulmonary metastatic lesions at week 6 are switched to chemotherapy with vincristine, dactinomycin, doxorubicin, cyclophosphamide, and etoposide (regimen M).[83]

COG high-risk (stage IV with LOH at 1p and 16q): vincristine, dactinomycin, doxorubicin, cyclophosphamide, and etoposide (regimen M).[84][86]

See local specialist protocol for dosing guidelines.

Primary options

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

Regimen M

vincristine

and

dactinomycin

and

doxorubicin

and

cyclophosphamide

and

etoposide

favorable histology: stage V

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

COG standard-risk (no LOH): abdominal/flank irradiation; patients with an incomplete/slow response of pulmonary metastatic lesions at week 6 receive whole lung irradiation.[83][84]

COG high-risk (LOH present): abdominal/flank irradiation and whole lung irradiation.[84][86]

Back

1st line –

preoperative chemotherapy

In patients with bilateral Wilms tumor or bilaterally predisposed unilateral Wilms tumor, preoperative chemotherapy is followed by nephron-sparing surgery and modified postoperative chemotherapy based on histologic response.[84][88][89]

The goal of preoperative chemotherapy is to shrink the tumor to allow maximum preservation of renal parenchyma.[89]

See local specialist protocol for regimen and dosing guidelines.

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

Radical nephrectomies can potentially be avoided and nephron-sparing surgery (e.g., unilateral total nephrectomy with contralateral partial nephrectomy, bilateral partial nephrectomy, unilateral total nephrectomy, and unilateral partial nephrectomy) used to preserve renal parenchyma and function.[88]

Partial nephrectomy may not be sufficient for high-risk patients due to a high incidence of recurrence.[90][91][92]

Consider – renal transplant

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Postoperative chemotherapy is based on histologic response.[84][88][89]

Each side should be individually staged and treated according to the guidelines above.

See local specialist protocol for regimen and dosing guidelines.

Back

Consider –

renal transplant

Treatment recommended for SOME patients in selected patient group

Rarely, disease is extensive bilaterally resulting in renal failure and need for a renal transplant.[93]

anaplastic histology: stage I

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Stage I patients with either focal or diffuse anaplasia receive vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[94]

See local specialist protocol for dosing guidelines.

Primary options

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

anaplastic histology: stage II

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

Stage I patients with either focal or diffuse anaplasia receive flank irradiation.[94]

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Treatment regimen depends on whether anaplasia is focal or diffuse.

Focal anaplasia: vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[95]

Diffuse anaplasia: vincristine, doxorubicin, cyclophosphamide, carboplatin, and etoposide (revised UH-1 regimen).[84][96]

See local specialist protocol for dosing guidelines.

Primary options

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

revised UH-1 regimen

vincristine

and

doxorubicin

and

cyclophosphamide

and

carboplatin

and

etoposide

anaplastic histology: stage III

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

Patients with focal or diffuse anaplasia should receive flank irradiation.[84][95]

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Treatment regimen depends on whether anaplasia is focal or diffuse.

Focal anaplasia: vincristine, dactinomycin, and doxorubicin (DD-4A regimen).[95]

Diffuse anaplasia: vincristine, doxorubicin, cyclophosphamide, carboplatin, and etoposide (revised UH-1 regimen).[84][96]

See local specialist protocol for dosing guidelines.

Primary options

DD-4A regimen

vincristine

and

dactinomycin

and

doxorubicin

revised UH-1 regimen

vincristine

and

doxorubicin

and

cyclophosphamide

and

carboplatin

and

etoposide

anaplastic histology: stage IV

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

Patients with focal or diffuse anaplasia should receive abdomen/flank irradiation, with a boost to residual tumor.[84][95]

Back

1st line –

surgery

Upfront nephrectomy using a transperitoneal approach is recommended for patients with unilateral renal masses who do not have a known Wilms tumor predisposition.[3][40]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Biopsy remains controversial, but an open biopsy with a minimum of 10-12 cores is required in the Children's Oncology Group (COG) protocol if a tumor is unresectable.[3][40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Patients with either focal or diffuse anaplasia receive revised UH-1 regimen, or UH-2 regimen (revised UH-1 with additional vincristine and irinotecan) in patients with poor/partial response to chemotherapy.[84][96]

See local specialist protocol for dosing guidelines.

Primary options

revised UH-1 regimen

vincristine

and

doxorubicin

and

cyclophosphamide

and

carboplatin

and

etoposide

UH-2 regimen

vincristine

and

doxorubicin

and

cyclophosphamide

and

carboplatin

and

etoposide

and

irinotecan

anaplastic histology: stage V

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

Patients with either focal or diffuse anaplasia receive abdomen/flank irradiation, with a boost to residual tumor.[84][95] Patients with lung metastasis receive whole lung irradiation.

Back

1st line –

preoperative chemotherapy

The goal of preoperative chemotherapy is to shrink the tumor to allow maximum preservation of renal parenchyma.[89]

See local specialist protocol for regimen and dosing guidelines.

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

Partial nephrectomy may not be sufficient for high-risk patients due to a high incidence of recurrence.[90][91][92]

Consider – renal transplant

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Postoperative chemotherapy is based on histologic response.[84][88][89]

Each side should be staged individually and treated according to the guidelines above.

See local specialist protocol for regimen and dosing guidelines.

Back

Consider –

renal transplant

Treatment recommended for SOME patients in selected patient group

Rarely, disease is extensive bilaterally resulting in renal failure and need for a renal transplant.[93]

SIOP criteria

stage I

Back

1st line –

preoperative chemotherapy

The UMBRELLA International Society of Paediatric Oncology (SIOP)-Renal Tumor Study Group (RTSG) 2016 protocol (known as the UMBRELLA protocol) recommends upfront chemotherapy for patients newly diagnosed with Wilms tumor ages ≥6 months prior to any attempt at resection regardless of initial stage.[55][75]

In patients <6 months old, the UMBRELLA protocol accounts for the risk of misdiagnosis of Wilms tumor by recommending direct surgery instead of preoperative chemotherapy.[41]

SIOP any risk: dactinomycin and vincristine (AV regimen) for 4 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

Consider – postoperative chemotherapy

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

After preoperative chemotherapy, radical tumor nephrectomy is the standard of care for all patients with Wilms tumor.[75] However, the SIOP UMBRELLA protocol has specified certain conditions in which nephron-sparing surgery is acceptable for nonsyndromic unilateral Wilms tumors: small tumor volume (<300 mL) and the expectation of a substantial remnant kidney function in patients with tumors <300 mL who never had lymph node involvement.[75]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Back

Consider –

postoperative chemotherapy

Treatment recommended for SOME patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

SIOP histologic classification divides patients with all stages (I through IV) into 3 groups: low-risk (completely necrotic Wilms tumor), high-risk (blastemal type and diffuse anaplasia), and intermediate-risk tumors (all other types).[41][55]

SIOP low-risk: no postoperative chemotherapy.

SIOP intermediate-risk: dactinomycin and vincristine (AV regimen) for 4 weeks.

SIOP high-risk: dactinomycin, vincristine, and doxorubicin (AVD regimen) for 27 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

AVD regimen

dactinomycin

and

vincristine

and

doxorubicin

stage II

Back

1st line –

preoperative chemotherapy

In patients <6 months old, the UMBRELLA protocol accounts for the risk of misdiagnosis of Wilms tumor by recommending direct surgery instead of preoperative chemotherapy.[41]

SIOP any-risk: dactinomycin and vincristine (AV regimen) for 4 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Consider – radiation therapy

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

SIOP low risk: dactinomycin and vincristine (AV regimen) for 27 weeks.

SIOP intermediate-risk (stromal or epithelial-type disease): AV regimen for 27 weeks.

SIOP intermediate-risk (nonstromal- or nonepithelial-type disease): dactinomycin, vincristine, and doxorubicin (AVD regimen) for 27 weeks.

SIOP high-risk: etoposide, carboplatin, cyclophosphamide, and doxorubicin (HR-1 regimen) for 34 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

AVD regimen

dactinomycin

and

vincristine

and

doxorubicin

HR-1 regimen

etoposide

and

carboplatin

and

cyclophosphamide

and

doxorubicin

Back

Consider –

radiation therapy

Treatment recommended for SOME patients in selected patient group

Flank irradiation is indicated in patients with high-risk diffuse anaplasia.[41]

stage III

Back

1st line –

preoperative chemotherapy

In patients <6 months old, the UMBRELLA protocol accounts for the risk of misdiagnosis of Wilms tumor by recommending direct surgery instead of preoperative chemotherapy.[41]

SIOP any risk: preoperative chemotherapy with dactinomycin and vincristine (AV regimen) for 4 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

SIOP low-risk: dactinomycin and vincristine (AV regimen) for 27 weeks.

SIOP intermediate-risk (tumor volume after preoperative chemotherapy <500 mL of any subtype or tumor volume ≥500 mL of stromal or epithelial-type disease): AV regimen for 27 weeks.

SIOP intermediate-risk (tumor volume ≥500 mL of nonstromal- or nonepithelial-type disease): dactinomycin, vincristine, and doxorubicin (AVD regimen) for 27 weeks.

SIOP high-risk: etoposide, carboplatin, cyclophosphamide, and doxorubicin (HR-1 regimen) for 34 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

AVD regimen

dactinomycin

and

vincristine

and

doxorubicin

HR-1 regimen

etoposide

and

carboplatin

and

cyclophosphamide

and

doxorubicin

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

SIOP low-risk: no irradiation.

SIOP intermediate-risk: flank irradiation is indicated.

SIOP high-risk: flank irradiation is indicated.

stage IV

Back

1st line –

preoperative chemotherapy

In patients <6 months old, the UMBRELLA protocol accounts for the risk of misdiagnosis of Wilms tumor by recommending direct surgery instead of preoperative chemotherapy.[41]

Chemotherapy regimen depends on staging and histology of tumor.

SIOP any risk: dactinomycin, vincristine, and doxorubicin (AVD regimen) for 6 weeks.

See local specialist protocol for dosing guidelines.

Primary options

AVD regimen

dactinomycin

and

vincristine

and

doxorubicin

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

After preoperative chemotherapy, radical tumor nephrectomy is the standard of care for all patients with Wilms tumor.[75]

Surgeon should avoid tumor spillage or incomplete removal. Selective sampling of lymph nodes should also be performed.[72]

Palpation of renal vein and inferior vena cava identifies any tumor thrombi (usually free-floating) and may allow for careful removal of thrombus.[40]

Any suspicious metastatic lesion (hepatic or intra-abdominal) should be either biopsied or resected.[40]

Back

Plus –

postoperative chemotherapy

Treatment recommended for ALL patients in selected patient group

Chemotherapy regimen depends on staging and histology of tumor.

SIOP low- or intermediate-risk (complete or very good partial remission of metastatic lesions to preoperative chemotherapy; representative metastatic nodule resection feasible and had completely necrotic metastasis): dactinomycin, vincristine, and doxorubicin (AVD regimen) for 27 weeks.

SIOP low- or intermediate-risk (partial remission of metastatic lesions to preoperative chemotherapy and resection of metastatic nodules; representative nodule resection confirmed viable metastasis or metastatic nodule resection is not feasible): etoposide, carboplatin, cyclophosphamide, and doxorubicin (HR-1 regimen) for 34 weeks.

SIOP high-risk: discuss best current treatment approach with the principal investigator for stage IV disease.

See local specialist protocol for dosing guidelines.

Primary options

AVD regimen

dactinomycin

and

vincristine

and

doxorubicin

HR-1 regimen

etoposide

and

carboplatin

and

cyclophosphamide

and

doxorubicin

Back

Plus –

radiation therapy

Treatment recommended for ALL patients in selected patient group

Pulmonary radiation therapy is only administered for lung metastases lacking complete response by postoperative week 10 and in all cases with high-risk tumors, despite response to treatment.[3][75]

Consider irradiation to metastases in low-risk disease if resection of nodule resection is not feasible.

Irradiation to metastases in intermediate- and high-risk disease is indicated.

stage V

Back

1st line –

preoperative chemotherapy

In bilateral Wilms tumor, preoperative chemotherapy with dactinomycin and vincristine (AV regimen) for a maximum of 12 weeks with evaluation of response at 6 weeks followed by surgery.

See local specialist protocol for regimen and dosing guidelines.

Primary options

AV regimen

dactinomycin

and

vincristine

Back

Plus –

surgery

Treatment recommended for ALL patients in selected patient group

Nephron-sparing surgery is advocated for bilateral disease; this may include tumorectomy, wedge resection, polar resection, heminephrectomy, nephrectomy on one side and partial resection, thus avoiding bilateral radical nephrectomies.[91]

The UMBRELLA protocol recommends discussion with the International Society of Paediatric Oncology-Renal Tumor Study Group (SIOP-RTSG) surgical panel to assess the feasibility of nephron-sparing surgery and minimize the risk of upstaging by incomplete resection of the tumor.[75]