Bilateral Wilms tumors (WT) treated with the SIOP 93 protocol in France: epidemiological survey and patient outcome.

BACKGROUND: The treatment of bilateral Wilms tumors (WT) requires multimodality therapy with individualized decision to ensure cure while preserving as much renal parenchyma as possible. PROCEDURE: We analyzed the clinical records of 49 children with bilateral WT treated in France between 1993 and 2001, according to the SIOP-93 guidelines (individual treatment program: Treatment was continued as long as there was imaging evidence of tumor regression). Pathology reports, duration of preoperative chemotherapy and surgical records were also reviewed. Overall Survival (OS) and Event-Free Survival (EFS) rates were studied and relationships between possible prognostic factors and survival were assessed. RESULTS: Imaging studies revealed bilateral involvement in 98% of the cases. Whatever the response to preoperative chemotherapy, the mean duration of neoadjuvant chemotherapy was 80 days (Q1-Q3: 47-89 days). Forty-eight children underwent nephron sparing surgery (NSS) at least for one kidney and 19 for both. Five-year EFS and OS rates were, respectively, 83.4 and 89.5%. Only the most advanced stages were shown to affect OS (P = 0.03). At study endpoint, end-stage renal disease (ESRD) was reported in seven children, associated with a predisposing phenotype in three. CONCLUSIONS: Results of this study demonstrate a favorable outcome of patients with bilateral WT receiving an individual treatment program. With a tailored approach to treatment according to the tumor response, 77% of our patients were operated before the third month of preoperative chemotherapy. In spite of good survival, 14% of our patients have ESRD.

Nephroblastoma: does the decrease in tumor volume under preoperative chemotherapy predict the lymph nodes status at surgery?

BACKGROUND: Partial nephrectomy (NSS) for unilateral nephroblastoma may be beneficial, although in case of regional lymph node (LN) involvement, radiotherapy counteracts the functional benefit of NSS. The aim is to verify whether decrease of tumor volume under preoperative chemotherapy implies clearance of regional LN. PROCEDURE: SIOP 9301 (1993-2001) collected 1,450 localized nephroblastoma patients of whom 1,360 (93%) had sufficiently available data and were retrospectively reviewed. RESULTS: Histologic subtypes were classically distributed. Patients were divided in those with tumor positive LN (76, 5.5%) and those with tumor negative LN (1,284, 94.5%) at surgery. In the LN(+) group, the tumor volume changed from a median of 554 (318-772) to 192 (63-458) ml = 67% (27-88%) during preoperative ChT. In the LN(-) group-377 (200-612) to 130 (44-294) ml = 62% (28-83%) (NS). Increase of tumor volume was observed in 16% of patients with LN(+), and 11% of those with LN(-) (NS); ranges are interquartile. Initial tumor volume was significantly larger in the LN(+) patients (P = 0.00091) but not different (NS) at surgery; patients with initial tumor volume under 318 ml had the regional LN involved significantly less frequently (P = 0.00751). CONCLUSIONS: Change in tumor volume under preoperative chemotherapy is not a predictor for LN status at surgery, although larger initial volume is associated with a higher risk of LN invasion. The decrease of tumor volume is not a good criterion for the safety of NSS. The low rate of LN(+) (5.5%) indicates that this risk is low.