Multidisciplinary approach to wilms' tumor: a retrospective analytical study of 53 patients

The aim of this work was to assess the epidemiologic aspects, clinico-pathological features and the results of multidisciplinary treatment of Wilms' tumor (WT) in pediatric patients treated at the National Cancer Institute (NCI), Cairo University, between January 2002 and December 2004.

This study included 53 patients, all under the age of 16 years, with previously untreated WT. Initial evaluation of all patients comprised laboratory investigations and radiological assessment which included chest X-ray and CT, abdomino-pelvic ultrasonography and CT. Doppler study of the renal vein and vena cava and bone scan were done when needed. Neoadjuvant chemotherapy was given to patients suffering from poor general condition, extensive tumor thrombus in the renal vein, irresectable and bilateral (stage V) nephroblastoma. Otherwise, up-front nephrectomy was the standard therapeutic approach in this study.

The age of the patients ranged from 2 to 108 months with a mean of 39.9 months (+/-22.56). Males and females were almost equal in number (50.9% and 49.1% respectively). Tumors were located in the left kidney in 52.8%, right kidney in 41.5% and bilaterally in only 5.7% of the cases. An abdominal mass was the most common clinical presentation (77.4%). Favorable histology was found in 86.3% while unfavorable histology was elicited in 13.7% of the cases. Congenital anomalies were recorded in 4 patients. Stage I and III were the most common (29.4% each), followed by stage II and IV (17.7% each), and finally by stage V (5.9%). Neoadjuvant chemotherapy was given to 27 cases while up-front nephrectomy was undertaken in 26 cases. Intra-operative spillage occurred in 12% of patients who had preoperative chemotherapy and 31% of those who had upfront nephrectomy. Postoperative abdominal radiotherapy was given to 32 patients. Twenty five patients underwent renal bed irradiation only, while in the other 7 whole abdominal irradiation was used. Additional chest bath (1200 cGy) was given to 7 patients. Complete remission (CR) was achieved in 74%, while death during neoadjuvant therapy took place in 4% of the cases. Disease progression during treatment was noticed in 8%. These patients were all treated with radio- and chemotherapy. Fatal outcome supervened in 75% of these, whereas in 25%, CR could be accomplished. Relapse after remission occurred in 14%. A 2nd CR could be achieved in 28.5% with a survival rate of 21.4%. Patients who relapsed >12 months after 1st CR had a 14 month-survival rate of 37.5% compared to 0% in those who relapsed <12 months after 1st CR. Disease-free survival (DFS) at 2 years was 82.4%, while overall survival (OAS) at 2 years was 78.9%. Therapy-related complications were mainly related to chemotherapy in 49% of patients and surgery in 5.9%.

Tight communication between the surgical, the medical and the radiation oncologists, together with the pathologist, is indispensable for better management of WT patients. Regional lymph node biopsy and accurate marking of residual disease are essential components of surgical treatment and heroic surgical attempts are unnecessary. Neoadjuvant chemotherapy, which is still a fertile source of debate, could possibly help to avoid excessive post-operative radiotherapy and its potential complications. Tumor stage and age of patient were found to affect the results of treatment of Wilms' tumor; but the only statistically significant determinant of prognosis was histologic differentiation. Finally, further studies including molecular markers are needed to augment therapy for the blastemal predominance subtype or for favorable histology associated with loss of heterozygosity (LOA) at chromosomes 1p and 16q aiming at improved survival.

Wilms' tumor - Nephroblastoma.