The impact of local control in the treatment of children with advanced infantile and adult-type FIBROSARCOMA: experience of the cooperative WEICHTEILSARKOMSTUDIENGRUPPE (CWS)

Abstract Background and objectives This study aims at examining the potential survival benefits of primary versus secondary surgery of children diagnosed with advanced infantile (iFS) and adult-type fibrosarcoma (aFS). Methods Treatment and outcome of 89 children with FS treated within prospective Cooperative Studiengruppe (CWS) trials (1981–2016) were analyzed retrospectively. Results Localized disease (LD) was diagnosed in 87 patients: 64/66 patients with iFS (≤ 2 years) and 23 with aFS (> 2 ≤ 18 years). Two patients (iFS) had metastatic disease. Resection was the mainstay of therapy of patients with LD resulting in microscopically complete (R0, IRS group I) (n = 29/87, 33%), microscopically incomplete (R1, IRS group II) (n = 17/87, 20%) and macroscopically incomplete (R2, IRS group III) (n = 41/87, 47%). Advanced LD (IRS group III) was present in 32/64 (50%) patients with iFS and in 9/23 (39%) with aFS. Chemotherapy was added predominantly in patients with advanced disease and an assessable objective response to CHT was seen in 71% iFS and 75% aFS. The 5-year event-free survival (EFS) of patients with iFS and aFS was 81% (± 10, 95% CI) and 70% (± 19, 95% CI) (p = 0.24); the 5-year overall survival (OS) was 98% (± 3, 95% CI) and 82% (± 16, 95% CI) (p = 0.02). Primary resection was no prognostic factor. Secondary R0/ R1 resection in patients with advanced disease improved 5-year EFS and OS in aFS (p = 0.002 and p = 0.000) but not in infants. Conclusions Secondary resection improves outcome in advanced aFS but not in infants. Mutilating surgery in infants should be avoided. Type of study and level of evidence Treatment study: patients were enrolled in five prospective studies and one registry, prognosis study: retrospective study. Level of evidence II/ III. Mini-abstract Fibrosarcoma is a very rare malignant tumor. Little is known about differences of local treatment of advanced infantile and adult-type. Data of 89 patients registered in five prospective trials and one registry of the Cooperative Weichteilsarkom Studiengruppe (CWS) (1981–2016) were analyzed.