RESUMEN
OBJECTIVE: To investigate the antitumor activity of a four-drug metronomic chemotherapy (MC) regimen in relapsed/progressing pediatric extracranial solid tumors (EST). The primary objective was clinical benefit (complete response /partial response/stable disease [SD]) after two cycles of therapy (four months). METHODS: Patients aged ≥4 to 25 years with progressing EST and adequate organ function were eligible. Treatment consisted of an eight-week cycle of oral celecoxib b.i.d., weekly vinblastine, and oral cyclophosphamide for three weeks alternating with oral methotrexate for three weeks, with a two-week rest. The Kepner-Chang two-stage model was used with 10 patients in the first stage. If primary objective was reached in two or more patients, eight additional patients were included according to four groups: neuroblastoma (NBL), soft-tissue sarcoma (STS), bone sarcoma (BS), and miscellaneous (Misc.). RESULTS: Forty-four patients were evaluable. The NBL cohort could be expanded to 18 patients: 4 of 18 patients stabilized with MC treatment for 6 (n = 1) and 12 (n = 3) months. In STS, two of seven patients (metastatic hemangioendothelioma and angiosarcoma) had SD for > 2 cycles. One of nine Misc. (metastatic myoepithelial carcinoma) had SD for one year. All patients with BS had progressive disease. One-year progression-free survival of the whole cohort was 6.8% and one-year overall survival was 55.3%. Grade 3 toxicity occurred in 18 patients and grade 4 in 15 patients. The most frequent toxicity was hematologic, predominantly neutropenia. CONCLUSIONS: This MC has no activity in BS and limited though interesting activity in NBL with some patients being stable for > 1 year. It is not possible to conclude activity in STS and Misc.