Singapore Rhabdomyosarcoma (RMS) Experience: Shall We Change Our Practice?

Abstract

Introduction: Although rhabdomyosarcoma (RMS) constitutes nearly 4% of all children diagnosed with cancer in the ethnically diverse small island city of Singapore, it is unknown how children with RMS fare. Materials and Methods: This study investigated 50 children with RMS from April 1993 to December 2010 from KK Women’s and Children’s Hospital (KKH) and National University Hospital (NUH). They were treated either as per Intergroup Rhabdomyosarcoma Study Group (IRSG) or Société Internationale Pediatrique D’Oncologie (SIOP) regimens. Results: Median age of diagnosis was 5.1 years (range, 0.1 to 17.3 years) with a median follow-up of 3.3 years (range, 0.4 to 15.6 years). According to IRSG classification, 18 (36%) were staged as low-risk (LR); 19 (38%) were intermediate-risk (IR), 12 (24%) were high-risk (HR) and it was unknown in 1 patient. Twenty-nine (58%) were of embryonal subtype, 17 (34%) were alveolar and subclassification was not available in 4. The primary sites of tumour were: head and neck region (n = 22); genitourinary (n = 19); extremity (n = 10); and abdomen/retroperitoneal (n = 5). At the time of analysis, 80% were alive with no evidence of disease, 9 were dead of disease, and 2 were alive with disease. By disease risk group, the 5-year event-free survival (EFS) for LR group disease was 81.3% (95% CI, 62.0 to 100.0), IR group was 61.4% (95% CI, 32.3 to 90.4) and HR group was 25.0% (95% CI, 0.0 to 49.5) respectively (P <0.001). The 5-year EFS for risk by chemotherapy received as per SIOP vs per IRSG revealed: LR 83.3% vs 75.0% (P = 0.787); IR 83.3% vs 43.8% (P = 0.351); HR 0.0% vs 42.9% (P = 0.336) respectively. Of 15 relapses (HR, n = 7), at median of 2 years, 4 of 6 patients treated as per SIOP regimen were dead of disease and 3 of 8 treated as per IRSG were alive. Conclusion: Radiation therapy (RT) can be avoided in LR classification although those in higher risk classification need RT to local and distant metastatic disease. The outcome of children with RMS in Singapore can be further improved by coming together as a cooperative group to provide the best total care. Improved communication, multidisciplinary team collaboration, standardisation of protocols and rigorous data collection are keys. Key words: Sarcoma, Survival, Treatment