Would you recommend prophylactic retro-peritoneal RT in an adolescent with paratesticular rhabdomyosarcoma, s/p radical inguinal orchiectomy without a lymph node dissection?

If a staging RPLND is NOT performed, is there a role for prophylactically irradiating the lymph nodes, even in the setting of a negative PET/CT at diagnosis in a >10 year old male with Rhabdomyosarcoma? If so, what RT field would you recommend?

1 Answer

Mednet Member

Radiation Oncology · St. Jude Children's Research Hospital

Answered on

Ideally, in children over 10 years of age with a diagnosis of paratesticular RMS, a retroperitoneal LN sampling (taking 7-12 LNs) at diagnosis should be performed unless obvious gross disease in the nodal region is present. The risk of occult LN involvement is higher in those children 10 years or older with some studies suggesting a risk over 40%. In the absence of this important pathologic staging information, a discussion should be had with the family describing the risks of understaging and the risks related to paraaortic irradiation. Factors such as primary tumor size (>5cm) and histology (alveolar/fusion positive) and imaging findings can guide the discussion towards recommending PA LN irradiation, but these factors are not absolute. If radiation is selected, 36 Gy is an appropriate dose and a fairly traditional paraaortic lymphatic field covering from above the level of the renal veins to the bottom of L4 would be appropriate.