Superior survival in children with rhabdomyosarcoma treated as per IRSG compared to as per SIOP regimen.

Abstract

Listen

Translate article

e20003 Background: Rhabdomyosarcoma (RMS) constitutes nearly 4% of all children diagnosed with cancer in ethnically diverse small island city of Singapore (pop. 5 million). Methods: We compared 56 children with RMS from April 1993 to December 2010 from KK Women’s and Children’s Hospital and National University Hospital, Singapore. They were treated as per Intergroup Rhabdomyosarcoma Study Group (IRSG) regimen (n=25), Société Internationale Pediatrique D’Oncologie (SIOP) regimen (n=20), and various other regimens (n=11). Results: Median age of diagnosis was 6.3 (0.1 - 17.3 years) with a median follow-up of 2.5 (0 - 15.6 years). According to IRSG classification, there were 19 (35.1%) with low risk (LR), 21 (38.8%) with intermediate risk (IR) and 14 (25.9%) with high risk (HR) disease. Fifteen (26.8%) were alveolar subtype, 23 (41.1%) were embryonal and sub-classification was not available in 18. The primary sites of tumor were: head and neck (n=22); genitourinary (n=19); extremity (n=10); and abdomen (n=5). At the time of analysis, 80.0% (n=45) were alive with no evidence of disease, 9 were dead of disease, and two were alive with disease. The 5-year EFS and OS for the cohort was 81.8% and 80.3% respectively. By disease risk group, 5-year EFS for LR was 93.3% [95% CI, 88.9 – 98.5], IR at 94.4% [95% CI, 90 – 99.6] and HR at 42.9% [95% CI, 41.5 – 47.7] respectively (p<0.001). The 5-year EFS for risk group by chemotherapy received per SIOP vs. per IRSG revealed: LR- 100% vs. 90.0% (p=0.43); IR- 100% vs. 90.9% (p=0.40); HR- 0% vs. 57.1% (0.64) respectively. Of 16 (7= HR) relapses at median of 2 years, 4 of 4 treated as per SIOP regimen were dead of disease and 2 of 3 treated as per IRSG were alive at last follow-up. Conclusions: High risk disease treated as per IRSG regimen resulted in superior EFS and OS than per SIOP. Although relapsed disease can be salvaged after initial therapy using SIOP regimen, emotional and financial impact of disease relapse on the family is vast. It would be of interest to report whether our findings can be duplicated in a collaborative international study.