Purpose: Chemotherapy is commonly used for treatment in children over three years old with high-risk medulloblastoma(MB). However, little is currently known about the therapeutic benefits and side effects of intrathecal methotrexate(MTX), warranting further research. Methods: In this retrospective study, patients who received intrathecal MTX during chemotherapy were included in the MTX group (n = 32), and patients that only underwent cerebrospinal fluid (CSF) cytology analysis were assigned to the control group (n = 14). Results: In the MTX group, 27(84.38%) patients had metastatic disease, 3(9.38%) had diffuse anaplasia, and 3(9.38%) had residual disease greater than 1.5 cm². Molecular subgroup classification was available for 28(87.5%) patients. In the control group, 8(57.14%) patients had metastatic disease, 3(27.27%) had diffuse anaplasia, and 6(42.86%) had residual disease greater than 1.5 cm². Molecular subgroup classification was available for 6(42.86%) patients. The 5-year progression-free survival was 70.99% and the 5-year overall survival was 72.99% for the MTX group, and the corresponding values were 41.67% and 50% for the control group, respectively. 6 (18.75%) patients in the MTX group with group 4 disease developed MTX-related acute leukoencephalopathy and one of them died. Conclusions: Our findings support the addition of intrathecal MTX during chemotherapy as the optimal management for children with group 3 and SHH high-risk MB. However, it is not recommended for group 4 MB patients, especially in resource-limited regions. Trial registration number: : Retrospective registered No.(2020 − 117).

Currently, no available coherent management protocol exists for pediatric cancers associated with pleural effusion, ascites, and pericardial effusion. This study aimed to retrospectively present our experience in treating pediatric cancer patients with pleural effusion, ascites, and pericardial effusion using interleukin-2 (IL-2) and dexamethasone (DEX) intracavitary injections. Between January 1st, 2008 and December 31st, 2020, medical reports of patients diagnosed with solid tumors or lymphoma were checked to identify patients diagnosed with > 2 cm pleural effusion, and/or more than grade 1 ascites, and/or more than small pericardial effusion. Patients diagnosed with effusions and treated with IL-2 and DEX were identified as being in the effusion group. Meanwhile, patients with the same primary tumors and effusions but did not receive interleukin 2 and DEX injection were reviewed and classified as the control group. Forty patients with solid tumors and 66 patients with lymphoma were further diagnosed with pleural effusion, ascites, or pericardial effusion. A total of 85 patients received IL-2 and DEX injection while the remaining 21 did not. The Kaplan Meier analysis revealed a significant difference between the two groups, with p < 0.01 for event free survival (EFS) and p < 0.01 for overall survival (OS), both of which had p < 0.01. Hazard ratio was found to be 0.344 for OS and 0.352 for EFS. This retrospective study illustrates that thoracic, intraperitoneal, or pericardial intracavitary injection of DEX plus IL-2 can be an effective and safe treatment for pediatric cancers with pleural effusion, ascites, and pericardial effusion.

Purpose: Spindle cell and sclerosing rhabdomyosarcoma (sRMS/scRMS) are rare variants accounting for 5%–10% of all RMS cases. This study aimed to evaluate the feasibility of using drug sensitivity assay to guide real time treatment decisions in children with sRMS/scRMS. Methods: We retrospectively analyzed 14 consecutive patients diagnosed with sRMS/scRMS between January 2020 and December 2024. All patients initially received two cycles of VAC (vincristine/dactinomycin/cyclophosphamide). If the tumor response is stable or progressive, subsequent treatment is tailored based on drug sensitivity assay. The primary endpoint was feasibility of drug sensitivity assay guided decision making. Secondary endpoints included objective response rate (ORR), PFS, and OS. Results: Drug sensitivity assay revealed uniform platinum sensitivity across all patients. After two cycles of VAC, 13 of 14 patients exhibited either stable or progressive disease, suggesting limited efficacy of the VAC regimen in this cohort. These 13 patients were subsequently transitioned to a platinum containing regimen guided by drug sensitivity assay, following which an objective response was observed in all cases. The 5-year PFS and OS were 36.92% (95% CI, 11.82–61.33) and 53.85% (95% CI, 31.70–82.93), respectively. Compared with the historical median survival of 9 months for relapsed/refractory RMS, the outcomes in our cohort appeared to be somewhat longer, suggesting a potential clinical benefit. The approach proved to be feasible in all 14 patients. Conclusion: Our findings suggest that drug sensitivity assay may represent a feasible and potentially useful tool for informing real time treatment decisions in children with sRMS/scRMS. The incorporation of such testing into the therapeutic algorithm for this chemotherapy resistant sarcoma variant may offer a means to individualize treatment and possibly improve prognostic outcomes. However, given the exploratory nature and limited sample size of this study, these observations should be interpreted with caution, and larger prospective studies are needed to confirm their validity.