Paratesticular rhabdomyosarcoma: report from the Italian and German Cooperative Group.

Purpose: We report the experience of the German-Italian Cooperative Group with 216 pediatric patients with paratesticular rhabdomyosarcoma treated over 20 years.

Patients And Methods: At diagnosis, 198 patients had localized disease and 18 had distant metastases. Among the nonmetastatic patients, complete tumor resection was performed in 83% of cases. Evaluation of the retroperitoneal lymph nodes changed over the years from routine surgical staging to radiologic assessment. All patients received chemotherapy, which was reduced in intensity and duration for patients with low-risk features in subsequent protocols. Radiotherapy was administered to 10% of patients.

Results: Among 72 patients with a negative retroperitoneal computed tomography (CT) scan, surgical assessment detected nodal involvement in only one case. Among 23 patients with enlarged nodes on CT scans, surgery confirmed nodal spread in 65% of patients. No differences in the rate of nodal involvement were observed over the years. With a median follow-up of 110 months, 5-year survival was 85.5% for the series as a whole, 94.6% for patients with localized disease, and 22.2% for metastatic cases. Retroperitoneal nodal recurrence was the major cause of treatment failure. Univariate analysis revealed the prognostic value of tumor invasiveness, size, and resectability, as well as of nodal involvement and age, in patients with localized tumor.

Conclusion: The outcome for patients with localized paratesticular rhabdomyosarcoma is excellent, despite the reduction in chemotherapy over the years: an alkylating agent-free and anthracycline-free regimen is adequate treatment for low-risk patients. Surgical assessment of the retroperitoneum must be reserved for patients with enlarged nodes on CT scans. Children over 10 years old carry a higher risk of nodal involvement and relapse.