| Abstract|| |
This is a retrospective study designed to find out the clinical profile of children with Wilms' tumor admitted to King Hussein Medical Center over a 6.5-year period. There were 26 patients (eight males and 18 females) with a median age of three years (range 1-8 years), at the time of diagnosis. Twenty children went into complete remission for a period ranging from 4-80 months (mean 46 months). Six children relapsed locally or with distant metastasis. All the six children with relapse died because of progressive disease. The overall relapse free survival was 77% for all stages (100%, 90%, 66.6%, 0% and 100% for stage I, II, III, IV and V respectively). This is similar to the international figures for stage I & II but is still behind for stage III & IV.
Keywords: Wilms′ tumor, Pathology, Survival, Children, Jordan.
|How to cite this article:|
Haddadin I, Hazza I. Wilms' Tumor Experience at King Hussein Medical Center. Saudi J Kidney Dis Transpl 2000;11:35-9
| Introduction|| |
Wilms' tumor (Nephroblastoma) originates in the developing renal tissue, the metanephrogenic blastema, and also found in combination with congenital anomalies. 
It is diagnosed annually in over 400 children in the United States.  The tumor is discovered more often by the parents than physicians. The firm irregular abdominal mass is the most common presentation.  Other presenting symptoms are abdominal pain, hematuria, fever, and gastrointestinal symptoms. Histological classifications are either favorable histology (FH) or unfavorable histology (UH). Pathological staging has become the best prognostic indicator for Wilms' tumor.  Significant advances have been made in the treatment of children with Wilms' tumor. Whereas overall survival was less than 10% 50 years ago, current survival estimates approach 90%. This progress has been made possible with the current chemotherapy, surgery and radiotherapy. 
This is a retrospective study designed to find out the clinical profile of children with Wilms' tumor in a center in Jordan.
| Material and Methods|| |
We reviewed the records of children with Wilms' tumor who were managed at King Hussein Medical Center in Amman-Jordan over the period between 1992-1998. Pretreatment investigations included complete blood count, urinalysis, kidney and liver function tests. The radiological investigations included chest X-ray, abdominal ultrasound, chest and abdominal CT scan. Fine needle aspiration biopsy (FNAB) or Tru cut biopsy under ultrasound guidance was performed for those with inoperable tumors.
The staging system was according to the National Wilms' tumor study (NWTS), which is based on the extent of disease at the time of surgery, whether immediate or delayed. Patients with primarily inoperable tumors were those with vena caval extension, huge tumor crossing the mid line and judged to be unresectable, and those with distant metastasis (stage V).
The pathologic types of the surgically resected tumor were favorable histology (FH) in 23 patients (88.5%) and unfavorable histology (UH) in 3 (11.5%). We considered the multicystic, tubular, and fibroadenomatous types as FH, while the anaplastic elements and sarcomatous changes as UH.
Surgery, chemotherapy, and radiotherapy were the three major modalities of treatment in our study patients. Chemotherapy comprised vincristine, actinomycin D, and adriamycin.
The length of treatment varied from stage one to five. For stage I, two drugs (Vincristine and Actinomycin-D) were administered for a period of three months. For stage II the same regimen was used for a period of six months and for stages III, IV and V the three drugs were given for one year.
Immediate surgical resection of the tumor was performed in stages I and II. For inoperable cases (stages III, 1V and V), a Tru-cut or FNAB was performed, and was tine, once weekly, and three cycles of actinomycin-D and adriamycin to eradicate the intravascular extension or to cause marked shrinkage of the tumor in order to facilitate surgical removal. Radiotherapy was used in four children with advanced stage or in case of local recurrence.
For those children who relapsed locally or had distant metastasis to the liver or the lungs, we used another chemotherapeutic protocol, which was composed of carboplatin and etoposid VP16.
| Results|| |
There were 26 children with the diagnosis of Wilms' tumor. The male to female ratio was 1:2.25 (8 male and 18 female), and the median age at time of diagnosis was three years (range 1-8 years).
The commonest clinical presentation was abdominal mass and the second common was abdominal pain, followed by hematuria, fever, and hypertension as [Table - 1]. In one child the investigations revealed that the tumor had extension to the right atrium via the inferior vena cava [Figure - 1],[Figure - 2].
Four patients (15.4%) were in stage I, ten patients (38.4%) in stage II, nine patients (34.6%) in stage III, two patients (7.6%) in stage IV, and one patient (3.8%) was in stage V.
Twenty children went into complete remission for a period ranging from four to eighty months (mean 46 months).
Six children relapsed; two of them relapsed while receiving chemotherapy, and the remaining four relapsed after 6-24 months of completing chemotherapy. All the six children who relapsed died because of progressive disease.
The relapse-free survival was 100%, 90%, 66.6%, 0% and 100% for stage I, II, III, IV and V, respectively. The overall relapse free survival for all stages was 77%.
| Discussion|| |
Jordan has a population of 4.3 million; of whom 40% are children under the age of 14 years (1994 official census). The estimated annual incidence of childhood cancer in Jordan is 119 per million children under the age of 14 years. Wilms' tumor accounts for about 4% of childhood cancers, which is approximately similar to the incidence of this tumor in other countries. , The main clinical presentation in our study was abdominal mass that was discovered by the parents. Rarely, patients presented with hematuria, fever and/or hypertension.
Preoperative chemotherapy is, nowadays, well established to decrease the surgical morbidity or mortality. Surgical rupture of the tumor was significantly decreased by preoperative chemotherapy as was demonstrated in the international society of pediatric oncology (SIOP) trial. 
Surgery and chemotherapy were the main modalities of treatment in our study. Radiotherapy was used only in few cases because in Jordan the facilities for radiotherapy are not optimal and young children account for the majority of patients with Wilms' tumor at our center. Therefore, radiotherapy was not used in the majority of patients in order to avoid side effects of radiation on growth and development.
One child aged one year with bilateral Wilms' tumor was treated successfully with chemotherapy alone and showed complete response, and follow-up abdominal CT scan showed complete remission. Such a case is usually treated with partial nephrectomy, chemotherapy, and radiotherapy, but only in few cases complete remission could be achieved with chemotherapy alone. 
In the one child who had extension of tumor-tissue to the right atrium via the inferior vena cava, the management included pre-operative chemotherapy, nephrectomy, followed by chemotherapy and radiotherapy to the tumor bed. Unfortunately, the child relapsed later on and died because of the progressive disease. 
The relapses of the tumor occurred in patients with stages II, III and IV of the disease. One child relapsed because the tumor ruptured during surgery with peritoneal seeding. Two patients relapsed because they had UH and two cases presented initially as stage IV. The relapse-free survival in this review is similar to reports from other series for stages I and II; while for the more advanced stages our results lag behind the international figures. In the United Kingdom, the results for Wilms' tumor treated within the United Kingdom Children Cancer Study Group (UKCCSG) showed remission in 95% for stages I and II, 82% for stage III, and 59% for stages IV with FH. 
We believe that early administration of effective agents such as carboplatin with etoposid may improve the prognosis of patients with high-risk Wilms' tumor (UH or advanced stage). The overall relapse-free survival of the 26 patients was 77%, which is acceptable in a country like Jordan.
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Pediatric Department, King Hussein Medical Center, P.O. Box 926119, Amman 11110
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2]