Background and aims: The outcomes of nephroblastoma (Wilms tumor, WT) in our institute and other developing countries are notably below results in most developed countries. The objective of this study was to review treatment outcomes of pediatric nephroblastoma in southern Thailand during the past decade and attempt to isolate factors associated with a poor prognosis.
Patients and methods: The records of 34 WT patients, aged less than 16 years, who were operated on in Songklanagarind Hospital, Thailand, during the period from January 1996 to December 2007 were reviewed. The management protocol followed the scheme of the US National Wilms Tumor Study Group (NSWTG).
Results: Thirteen cases (38.2%) were diagnosed as stage I, 4 (11.8%) as stage II, 13 (38.2%) as stage III and 2 (5.9%) as stage IV. Two cases with bilateral disease (stage V) had stage I tumors in both kidneys. Four-year overall survival (OS) and event free survival (EFS) rates were 65.2% and 52.7%, respectively. Univariate analysis by Log-rank test revealed statistically significant associations between OS and nodal status (p-value <0.01), manifestation of gross hematuria (p-value 0.02), and tumor size of 10 centimeters or more (p-value 0.02). Multivariate analysis found only the nodal status to be independently associated with OS at a Hazard Ratio of 16.6 (p-value <0.01). Eight of 13 stage I cases and 6/13 stage III cases had relapsed, with two-year post-relapse survival of 42.8%. Significantly poorer outcome was found in cases with early relapse within 200 days after enrolment (p-value 0.02).
Conclusion: The poor outcome of pediatric nephroblastoma in southern Thailand seems to be related at least in part to failures in primary treatment in stage I patients. Large tumor size and gross hematuria were associated with risk of a poorer outcome.