Commentary on Wilms' tumour

Outcome of localised blastemal-type Wilms tumour patients treated according to intensified treatment in the SIOP WT 2001 protocol, a report of the SIOP Renal Tumour Study Group (SIOP-RTSG)

Blastemal-type Wilms tumour (BT-WT) has been identified as a high risk histological subgroup in WT assessed after pre-nephrectomy chemotherapy in trials of the International Society of Paediatric Oncology (SIOP) Renal Tumour Study Group. Therefore, in SIOPWT2001, post-operative chemotherapy for BT-WT was intensified aiming to improve survival. Survival analysis of all unilateral BT-WT patients (SIOPWT2001) (n=238), was compared with historical BT-WT controls (SIOP93-01) (n=113). 351/4061 (8.6%) unilateral non-metastatic BT-WT patients (SIOP93-01/SIOPWT2001) were studied. Median age at diagnosis was 43 months (Inter Quartile Range (IQR) 24-68 months), stages: I (n=140, 40%), II (n=106, 30%), III (n=105, 30%). BT-WTs were higher staged, showed greater volume decrease after pre-operative chemotherapy and were diagnosed at an older median age compared to other WT patients. Patient characteristics did not differ substantially between SIOP93-01 and SIOPWT2001. Univariate analysis showed a 5-year event-free survival (EFS) of 80% (95% confidence interval (CI): 75-86%) (SIOPWT2001) compared to 67% in SIOP93-01 (95% CI: 59-76%; p=0.006) and overall survival (OS) of 88% (95% CI: 83-93%) (SIOPWT2001) compared to 84% (95% CI: 77-91%; p=0.4) in SIOP93-01. 95% of relapses were distant metastases (SIOP93-01/SIOPWT2001). Treatment protocol, age at diagnosis, tumour stage (III versus I/II) and volume (at surgery), were prognostic variables for EFS (uni- and multivariate Cox regression analysis). Independent prognosticators for OS were age at diagnosis, tumour stage and volume (at surgery). The most significant survival benefit of intensified treatment, was observed in Stage I (EFS 96% in SIOPWT2001 (OS 100%), 71% in SIOP93-01 (OS 90%)). BT-WT derived benefits from more intensive chemotherapy as reflected by a reduction in relapse risk. However, the benefit of the more intensive chemotherapy to improve OS was only observed in stage I BT-WTs, by adding doxorubicin.

Surgical complications after immediate nephrectomy versus preoperative chemotherapy in non-metastatic Wilms' tumour: findings from the 1991-2001 United Kingdom Children's Cancer Study Group UKW3 Trial

PURPOSE

To compare surgical complication rates after immediate nephrectomy versus delayed nephrectomy following preoperative chemotherapy in children with non-metastatic Wilms' tumour enrolled in UKW3, both in randomised patients and in those for whom the treatment approach was defined by parental or physician choice.

METHODS

Records for all patients enrolled into UKW3 were reviewed. Any record of tumour rupture or surgical complication was extracted and comparisons made between the two treatment strategies in both populations of randomised and non-randomised patients.

RESULTS

Of 525 children enrolled, 205 patients were randomised to either immediate nephrectomy (n=103) or pre-operative chemotherapy followed by delayed nephrectomy (n=102). Of the 320 children not randomised, data were available on 189 cases treated with immediate nephrectomy and 103 treated with pre-operative chemotherapy. There were significantly fewer surgical complications in randomised children given pre-operative chemotherapy before surgery compared to children undergoing immediate nephrectomy (1% vs. 20.4%, P<0.001); this difference was most marked for tumour rupture (0% vs. 14.6%, P<0.001).

CONCLUSIONS

Delayed nephrectomy for Wilms' tumour, preceded by pre-operative chemotherapy was associated with fewer surgical complications compared with immediate nephrectomy.