Fibrosarcoma in pediatric patients: Results of the Italian Cooperative Group Studies (1979-1995)

BACKGROUND AND OBJECTIVES: Fibrosarcoma is a rare soft tissue sarcoma (STS) that has two peaks of incidence in pediatric patients: one in infants and young children (infantile fibrosarcoma), another in older children ("adult type" fibrosarcoma). The purpose of this study was to describe the clinical features and the treatment results in patients affected by fibrosarcoma enrolled in two consecutive studies run by the STS-Italian Cooperative Group (ICG) between 1979 and 1995. PATIENTS AND METHODS: Twenty-five evaluable patients were grouped according the intergroup rhabdomyosarcoma staging (IRS) system: 12 Gr I, 5 Gr II, 8 Gr III. The cut-off point between the two forms was considered the age of 2 years: 14 patients were affected by infantile and 11 by adult type of fibrosarcoma. The therapeutic guidelines were not strict and not different for the two forms: patients with initial macroscopic excision (Gr I-II) were given IVA or VAC; Gr III had VAC or VAIA and subsequent excision, if feasible. Radiation therapy (RT) was delivered in patients > 3 years with microscopic (42 Gy) and macroscopic (54 Gy) residuals. RESULTS: Thirteen patients are alive without evidence of disease: 10 in first complete remission (CR), 7 Gr I, 1 Gr II, 2 Gr III, 3 in second CR after local relapse (LR) (2 Gr I, 1 Gr II). Two Gr I patients are alive with metastatic relapse. Nine patients died: six of progressive disease (PD) (three Gr II, three Gr III), two because of a second tumor (one Gr I, one Gr III) and one because of other causes (Gr III). One Gr III patient was lost at follow up, 2 years from diagnosis. The 10 years overall survival (OS) is 67.4% and the progression-free survival (PFS) is 52.2%. The OS for patients < 2 years is 78.6% (11 of 14), versus 51% for patients > 2 years (5 of 11). CONCLUSIONS: The complete excision at diagnosis was the treatment of choice and was related to the best outcome. Microscopical residuals were difficult to treat with chemo-radiotherapy in both forms of fibrosarcoma. Neoadjuvant chemotherapy (CT) obtained a partial remission (PR) only in three of eight cases, while no conclusions concerning the efficacy of CT for infantile forms are possible. Patients < 2 years had a better outcome than the older ones: most of them had a tumor on extremities which was excised at diagnosis.