Role of surgery for nonmetastatic abdominal rhabdomyosarcomas: a report from the Italian and German Soft Tissue Cooperative Groups Studies.

Background: In the current study, the authors aim to evaluate clinical features and treatment results observed in patients from the German and Italian studies who had nonmetastatic abdominal rhabdomyosarcomas (RMS).

Methods: One hundred sixty-one patients were observed; 78 registered in the German studies between October 1980 and August 1995, and 83 registered in the Italian studies between April 1975 and December 1995. The age range of the patients was 0-18 years (median, 4 yrs). The distribution of tumor sites was as follows: 32 intraperitoneal, 42 retroperitoneal, 75 pelvic, and 12 not otherwise specified (NOS). Most patients had a large and invasive primary mass (26 T1b, 114 T2b). The breakdown in histology was as follows: 116 embryonal, 34 alveolar, and 11 other (leiomyomatous, pleomorphic, and NOS); all cases were staged according to the Intergroup Rhabdomyosarcoma Studies (IRS) system. Nine Group I patients were treated after surgery with chemotherapy (CT) (radiotherapy [RT] was delivered to treat alveolar RMS in the 1991 German and 1988 Italian studies); 19 Group II patients received CT + RT (40-44 Gy); 133 Group III patients underwent neoadjuvant CT +/- surgery and/or RT (54 Gy) + CT. Different CT regimens (based primarily on the administration of vincristine, dactinomycin, doxorubicin, and cyclophosphamide or ifosfamide) were adopted. RT was not recommended for patients age < 3 years.

Results: The 10-year overall survival (OS) and progression-free survival (PFS) were 47.2% and 43.9%, respectively. The OS was related significantly to the following variables: histology (alveolar, 29.4% vs. nonalveolar, 52.1% [P = 0.0156]), tumor size (> 5 cm, 42.1% vs. < 5 cm, 81% [P = 0.005]), age (< 10 yrs, 51.4% vs. >or= 10 yrs, 27.8% [P = 0.02]), complete surgery at diagnosis or after CT (+/-RT) (70.4% vs. 34.4% without it [P = 0.0015]). Most patients who achieved the delayed local control had responded well to neoadjuvant CT.

Conclusions: Tumor size, histology, age, and initial or delayed achievement of local control were important prognostic factors. Most relapsed patients had unfavorable outcomes.