1. Patient characteristics
Eighteen patients were enrolled with a median age at initiation of MC of 7.3 years (range, 2.7–16.1 years), and the sex ratio was 1:1. Seven patients were diagnosed with brain tumors, including 2 cases of atypical teratoid/rhabdoid tumor, 2 cases of ependymoma, and 1 case each of medulloblastoma, mixed germ cell tumor, and infantile hemispheric glioma. The remaining 11 tumors were 4 cases of neuroblastoma (NBL), 3 cases of rhabdomyosarcoma (RMS), and 1 case each of Ewing sarcoma, malignant peripheral nerve sheath tumor (MPNST), desmoplastic small round cell tumor, and extrarenal rhabdoid tumor.
The median time from diagnosis to MC initiation was 28 months (range, 14–84 months). The reasons for starting MC and disease status at that time were as follows: 2 patients with RMS and MPNST achieved CR and received MC as maintenance therapy; and 5 patients had PR to prior therapies or maintained SD without relapse (4 patients from this group received MC as consolidation therapy and the remaining patient with NBL received MC as a bridging therapy to 131-iodine-metaiodobenzylguanidine therapy). The remaining 11 patients received MC as palliative therapy for tumors that showed PD to conventional chemotherapies.
The choice of treatment regimen was at the discretion of the attending physician and was mainly set according to the newly published trials data available at the time.4–10 Antiangiogenic agents, including bevacizumab, celecoxib, and fenofibrate, were combined when deemed appropriate. Two patients with RMS received a combination therapy of oral cyclophosphamide and intravenous vinorelbine, which was developed as maintenance therapy for primary RMS.17
Detailed characteristics of each patient are shown in Table 1. Of the 18 patients, 16 had received cyclophosphamide and 18 had received etoposide with a cytotoxic dose before MC—indicating no impact to the treatment outcomes of MC.