Management of Rhabdomyosarcoma (RMS)

Diagnostic Evaluation

The European Society for Medical Oncology (ESMO) guidelines recommend that any unexplained deep soft tissue mass, superficial lesion >5 cm, or any soft tissue mass in pediatric patients warrants referral to a sarcoma reference center 9
Plain radiographs should be obtained first to rule out bone tumors, detect bone erosion, and identify calcifications 9
MRI with contrast enhancement is the preferred imaging modality for extremity and trunk wall tumors, providing the most accurate information for diagnosis and surgical planning 9
Multiple core needle biopsies using needles >16G are the standard diagnostic approach 9
Core biopsies should be performed under imaging guidance to avoid necrotic areas 9
The biopsy tract must be planned so it can be safely removed during definitive surgery 9
Tumor samples should be fixed in formalin; avoid Bouin fixation as it prevents molecular analysis 9
Embryonal rhabdomyosarcoma must be identified by immunohistochemistry and cytogenetics 1, 4, 5, 6, 7, 8
Molecular pathology (FISH, RT-PCR) should complement morphology and immunohistochemistry when the clinical-pathological presentation is unusual or the specific histological diagnosis is doubtful 9

Chest CT scan is mandatory for staging to exclude pulmonary metastases 2, 9
Abdominal/pelvic CT should be considered for specific histologic subtypes with high metastatic potential 9
Physical examination and appropriate radiological techniques complete the staging evaluation 1, 4, 5, 6, 7, 8

RMS requires a multidisciplinary approach by an experienced team 1, 4, 5, 6, 7, 8
Surgery is the main treatment for localized disease 1, 2, 4, 5, 6, 7, 8
The tumor should be removed by wide excision or compartmental resection, including the cutaneous scar and biopsy tract 1, 4, 5, 6, 7, 8
Re-operation is recommended in cases of previous marginal or intralesional resection 4, 5, 6, 7, 8
After wide excision of high-grade sarcomas, adjuvant radiation therapy is recommended 1, 2, 4, 5, 6, 7, 8
The standard postoperative radiation dose is 50-60 Gy in fractions of 1.8-2 Gy, with possible boosts up to 66 Gy depending on presentation and quality of surgery 2, 3, 10
Preoperative radiotherapy typically uses a dose of 50 Gy 2, 3
For hypofractionated regimens, 50 Gy in 20 fractions (2.5 Gy per fraction) is recommended 10
For compromised margins, consider an additional boost of 16-18 Gy for microscopically positive margins and 20-26 Gy for macroscopic residual disease 10
Surgery should be performed 4-8 weeks after completion of preoperative radiotherapy 10

Chemotherapy is the standard treatment for metastatic disease 1, 4, 5, 6, 7, 8
Doxorubicin with or without ifosfamide is commonly used for metastatic soft tissue sarcomas 1, 4, 5, 6, 7, 8
Response evaluation should be performed after 2 or 3 cycles with the radiological exams that were positive before treatment 1, 4, 5
In cases of completely resectable lung metastases, surgery should be considered 4, 5, 6, 7, 8

Patients should be followed every 3 months with history and physical examination 1, 4, 5
MRI of the resection site is proposed twice yearly for the first 2-3 years, then once yearly 1, 4, 5
For high-grade tumors, chest X-ray is recommended every 3-4 months in the first 2-3 years, twice yearly up to the 5th year, and once yearly thereafter 1, 4, 5