Clinical features and results of therapy for children with paraspinal soft tissue sarcoma: a report of the Intergroup Rhabdomyosarcoma Study.

Abstract

Soft tissue sarcomas of the paraspinal region comprised 3.3% (56 of 1,688) of the patients entered and eligible on Intergroup Rhabdomyosarcoma Studies I (IRS-I) and II (IRS-II) (1972 to 1984). These lesions tended to be greater than 5 cm in diameter at diagnosis, invaded the spinal extradural space, and were of the extraosseous Ewing's sarcoma or undifferentiated sarcoma subtype in 55% (30 of 56) of the cases. Patients with tumors in clinical groups II, III, and IV were treated with radiotherapy (XRT) and vincristine-dactinomycin (VA) or VA plus cyclophosphamide (VAC) +/- doxorubicin. Clinical group I patients treated on IRS-II did not receive XRT, while those on IRS-I were randomized to receive VAC +/- XRT. Forty-four of the paraspinal patients (79%) achieved a complete response (CR) compared with 77% (1,260 of 1,632) for patients with disease in other sites. Twenty-seven patients (55%) subsequently relapsed (five local, three regional, four local and distant, and 14 distant). The proportion of patients surviving 5 years by clinical group (stage) from I to IV were 50%, 50%, 62%, and 27%, respectively. Paraspinal patients had somewhat poorer survival than patients with disease in other sites, both in IRS-I and IRS-II; the percentage of paraspinal patients surviving 5 years was 50% and 52% for IRS-I and IRS-II, respectively, whereas these percentages were 55% and 63% for patients with disease in other sites. Histology did not influence the CR rate, but unexpectedly, patients who had embryonal rhabdomyosarcoma (RMS) had the poorest overall survival rate. We concluded that patients with paraspinal lesions may require extended-field radiation therapy to reduce the high local failure rate and more intensive chemotherapy to achieve better local and systemic tumor control.