Paratesticular rhabdomyosarcoma in children and adolescents-Outcome and patterns of relapse when utilizing a nonsurgical strategy for lymph node staging: Report from SIOP Malignant Mesenchymal Tumour 89 and 95 studies.

Paratesticular rhabdomyosarcoma in children and adolescents-Outcome and patterns of relapse when utilizing a nonsurgical strategy for lymph node staging: Report from SIOP Malignant Mesenchymal Tumour 89 and 95 studies.
Surgical staging with ipsilateral retroperitoneal lymph node sampling is currently required for all children aged 10 years and older with paratesticular rhabdomyosarcoma on COG-STS studies. However, node dissection was not routine in Europe for adolescents with resected paratesticular rhabdomyosarcoma. Many European investigators relied on radiographic, rather than surgical-pathologic assessment, for retroperitoneal lymph node involvement because of the high morbidity of the surgical assessment. This study aims to review all patients with nonmetastatic paratesticular RMS enrolled in International Society of Paediatric Oncology (SIOP) Malignant Mesenchymal Tumour (MMT) 89 and 95 trials and to report the outcomes and patterns of relapse when utilizing a nonsurgical strategy for lymph node (LN) staging.
Patients with paratesticular rhabdomyosarcoma were evaluated with imaging but did not undergo routine ipsilateral lymph node sampling. Biopsy or fine-needle aspiration cytology was performed on regional nodes if there was clinical or radiologic uncertainty about LN involvement.
159 patients with localized paratesticular RMS were included in this study between 1989 and 2003. 25% of these patients were more than 10 years of age. Thirty-one percent of stage N0 patients of age ≥10 years developed node relapse, compared with
8% of N0 patients aged 5 years (42%) and three nodal relapses occurred in 15 patients with tumors >5 cm (20%, P = 0.27) (size was unknown for one patient).
When nodal relapse occurred in this group, it was predominantly in patients with tumors >5 cm. This was not statistically significant likely due to the size of the population. This study did not explore if there is a superiority of one of the 3 different radiological imaging (US, CT, MRI). Finally, the utilization of PET scan as part of the disease staging is also a possible way to improve staging without the morbidity of surgical assessment. It is something that can eventually be explored.
Older patients with paratesticular rhabdomyosarcoma (≥10 years) have a significant risk of LN relapse. These results support a surgical approach to LN staging in this subgroup of patients. The SIOP MMT group subsequently recommended ipsilateral lymph node sampling for all patients aged 10 years and older.