Outcome, Treatment, and Treatment Failures in Patients Suffering Localized Embryonal Paratesticular Rhabdomyosarcoma: Results From the ”cooperative Weichteilsarkom Studiengruppe” Trials Cws-86, -91, -96, and -2002p

Objective: To evaluate outcome in respect to local treatment strategies in 4 prospective CWS trials in patients with paratesticular rhabdomyosarcoma (PTRMS). Summary Background Data: PTRMS patients have a high number of surgical treatment failures. Retroperitoneal lymph node (LN) involvement is common in patients more than 10 years, and the optimal treatment is unknown. Methods: A total of 173 patients with diagnosis of PTRMS were enrolled. Of these, 26 were excluded and 147 patients were finally analyzed. All patients were treated according to the Cooperative Soft Tissue Sarcoma (CWS) trial protocols. Results: The 5-year overall survival was 95.5%, and the 5-year event-free survival (EFS) was 89.8%. Positive predictive factors for EFS were age younger than 10 years and tumor size less than 5 cm. Surgical treatment failures were observed in 34 of 135 patients undergoing primary resection. Primary inguinal/iliacal LN sampling was carried out in 15 of 147 patients with no impact on the EFS (87.5%; P = 0.666). Secondary retroperitoneal LN dissection was done in 32 of 147 patients, of which only 8 patients had viable tumor and a worse outcome (EFS: 50%; P = 0.01). Loco-regional, combined, and metastatic relapses were observed in 13 of 147 patients. Conclusions: The outcome of PTRMS patients is excellent and is hardly improvable. Positive predictors for outcome are age younger than 10 years and tumor size less than 5 cm. Primary LN sampling seems to have no impact on the EFS and should not be recommended. Inadequate surgery can be avoided by treatment in specialized centers. Secondary retroperitoneal LN dissection revealed a high number of unnecessary procedures, but patients with positive LN had a poor prognosis and require additional local therapy.