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.Rhabdomyosarcoma (RMS) constitutes nearly 4% of all children diagnosed with cancer in the ethnically diverse small island city of Singapore. It is the most common primary soft tissue malignancy of childhood and one which is highly sensitive to chemotherapy and radiation therapy leading to excellent overall survivals. In KK Women’s and Children’s Hospital (KKH), majority of the children were treated according to the European Société Internationale Pediatrique D’Oncologie (SIOP) regimen whilst in National University Hospital (NUH), children were treated as per the American Intergroup Rhabdomyosarcoma Study Group (IRSG) regimen as described elsewhere. The 2 regimens differ in the use of radiation therapy (RT) as a salvage treatment modality for relapsed disease in the former versus upfront radiation in all alveolar and higher risk disease in the latter. Several clinical and disease characteristics predict the outcome in children with RMS including age at diagnosis, stage, group, location of primary tumour and histology. According to the IRSG, staging is done in 3 basic steps: presurgical staging based on imaging studies, postsurgical grouping and finally risk group. Risk is divided into 3 prognostic groups, low-risk (LR), intermediate-risk(IR), or high-risk (HR) subgroups based on estimated failure-free survival differences (Table 1). We set out to investigate the patient and tumour characteristics and the outcome based on the 2 varied regimens used in the care of these children diagnosed with this uncommon disease in Singapore.
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