Soft tissue sarcoma or malignant mesenchymal tumors in the first year of life: experience of the International Society of Pediatric Oncology (SIOP) Malignant Mesenchymal Tumor Committee

Abstract

Purpose: To describe the outcome of infants with a histologically confirmed diagnosis of malignant mesenchymal tumor (MMT) included in the International Society of Paediatric Oncology studies MMT 84 and MMT 89.

Patients and methods: One hundred two infants (< or = 12 months old) were included. Twenty-four children were less than 3 months old, and 16 were less than 1 month old. Sixty-four patients had rhabdomyosarcoma (RMS), 26 had undifferentiated sarcoma, and 12 had other histology. Clinical TNM stage was stage I (41%), II (39%), III (6%), and IV (14%). First-line treatment was ifosfamide, vincristine, dactinomycin, whereas the second-line combination consisted of either cisplatin and doxorubicin (in MMT 84) or vincristine, carboplatin, etoposide/teniposide (in MMT 89). Chemotherapy doses were adapted to age. Local therapy was conservative surgery as often as possible.

Results: After a median follow-up of 7.8 years (range, 0.1 to 13 years), 5-year overall survival (OS) and event-free survival rates were 66% and 55% for the total study population and 72% and 60% for nonmetastatic patients, respectively. Only two of 13 stage IV patients survived. Sixty-seven percent of newborn infants survived. Infants with alveolar subtype had a poorer survival than those with non-RMS MMT or nonalveolar RMS (5-year OS, 37% v 75% or 82%, respectively; P = .002). When compared with older children with MMT, young age does not seem to be an important prognostic factor.

Conclusion: OS was satisfactory even when local treatment was not aggressive, although the prognosis was poor for infants with alveolar RMS or metastatic tumors. Chemotherapy toxicity was manageable with appropriate dose modification.