What have we learnt from previous phase II trials to help in the management of childhood brain tumours?

The effectiveness and safety of proton beam radiation therapy in children and young adults with Central Nervous System (CNS) tumours: a systematic review

BACKGROUND

Central nervous system (CNS) tumours account for around 25% of childhood neoplasms. With multi-modal therapy, 5-year survival is at around 75% in the UK. Conventional photon radiotherapy has made significant contributions to survival, but can be associated with long-term side effects. Proton beam radiotherapy (PBT) reduces the volume of irradiated tissue outside the tumour target volume which may potentially reduce toxicity. Our aim was to assess the effectiveness and safety of PBT and make recommendations for future research for this evolving treatment.

METHODS

A systematic review assessing the effects of PBT for treating CNS tumours in children/young adults was undertaken using methods recommended by Cochrane and reported using PRISMA guidelines. Any study design was included where clinical and toxicity outcomes were reported. Searches were to May 2021, with a narrative synthesis employed.

RESULTS

Thirty-one case series studies involving 1731 patients from 10 PBT centres were included. Eleven studies involved children with medulloblastoma / primitive neuroectodermal tumours (n = 712), five ependymoma (n = 398), four atypical teratoid/rhabdoid tumour (n = 72), six craniopharyngioma (n = 272), three low-grade gliomas (n = 233), one germ cell tumours (n = 22) and one pineoblastoma (n = 22). Clinical outcomes were the most frequently reported with overall survival values ranging from 100 to 28% depending on the tumour type. Endocrine outcomes were the most frequently reported toxicity outcomes with quality of life the least reported.

CONCLUSIONS

This review highlights areas of uncertainty in this research area. A well-defined, well-funded research agenda is needed to best maximise the potential of PBT.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO-CRD42016036802.

Activity of the polyamine-vectorized anti-cancer drug F14512 against pediatric glioma and neuroblastoma cell lines

The poor prognosis of children with high-grade glioma (HGG) and high-risk neuroblastoma, despite multidisciplinary therapeutic approaches, demands new treatments for these indications. F14512 is a topoisomerase II inhibitor containing a spermine moiety that facilitates selective uptake by tumor cells via the Polyamine Transport System (PTS) and increases topoisomerase II poisoning. Here, F14512 was evaluated in pediatric HGG and neuroblastoma cell lines. PTS activity and specificity were evaluated using a fluorescent spermine-coupled probe. The cytotoxicity of F14512, alone or in combination with ionizing radiation and chemotherapeutic agents, was investigated in vitro. The antitumor activity of F14512 was assessed in vivo using a liver-metastatic model of neuroblastoma. An active PTS was evidenced in all tested cell lines, providing a specific and rapid transfer of spermine-coupled compounds into cell nuclei. Competition experiments confirmed the essential role of PTS in the cell uptake and cytotoxicity of F14512. This cytotoxicity appeared greater in neuroblastoma cells compared with HGG cells but appeared independent of PTS activity levels. In vivo evaluation confirmed a marked and prolonged antitumoral effect in neuroblastoma cells. The combinations of F14512 with cisplatin and carboplatin were often found to be synergistic, and we demonstrated the significant radiosensitizing potential of F14512 in the MYCN-amplified Kelly cell line. Thus, F14512 appears more effective than etoposide in pediatric tumor cell lines, with greater efficacy in neuroblastoma cells compared with HGG cells. The synergistic effects observed with platinum compounds and the radiosensitizing effect could lead to a clinical development of the drug in pediatric oncology.

[The role of chemotherapy in pediatric medulloblastoma]

Medulloblastoma is one of the most frequent brain tumors in childhood. The mortality of medulloblastoma decreased significantly during the last few decades, which was the result of the better surgical and radiotherapeutic methods and of the development of chemotherapy. The aim of this publication is the critical review of the present chemotherapeutic treatment. The new therapeutic trials based on the molecular genetic mechanism of these tumors are also mentioned.

[Diffuse intrinsic brain stem glioma in children: current treatment and future directions]

Despite the numerous clinical trials undertaken, the prognosis of children with diffuse brain stem glioma remains very poor. This review examines the different strategies for the treatment of malignant brain stem glioma such as radiation therapy, concurrent radiochemotherapy, and classical cytotoxic drugs, with a particular focus on the novel targeted and antiangiogenic drugs recently introduced in pediatric oncology. The strategy using integrin inhibitors is discussed.

Outcome of children treated with preradiation chemotherapy for a high-grade glioma: results of a French Society of Pediatric Oncology (SFOP) Pilot Study

BACKGROUND

To evaluate the efficacy of BCNU, cisplatin, and vincristine (BCV regimen) in a prospective nonrandomized study among newly diagnosed children with high-grade glioma.

PROCEDURE

Following surgery, patients received a combination of BCNU + cisplatin + VP16 (BCV), over 3 consecutive days. Patients with residual tumor continued this regimen unless no further improvement was observed on MRI, for a maximum of six courses. Patients who underwent complete surgical resection received six courses of adjuvant BCV.

RESULTS

Seventy-three patients were enrolled. Out of 66 eligible patients with central pathology review, the diagnosis of high-grade glioma was confirmed in 53 cases. The response rate was 20%. With a median follow-up of 128 months, 5- and 10-year event free survival rates are 16 +/- 9 and 13.3 +/- 9.4%. In univariate analysis, two prognostic factors were statistically significant: extent of resection and tumor location, while macroscopic total resection was the only significant prognostic factor in the multivariate analysis. The response to BCV did not translate into improved event free survival. Interstitial pneumonitis occurred in seven patients, leading to six deaths.

CONCLUSION

This BCV regimen could not be recommended in the treatment of high-grade gliomas in children, according to its lack of efficacy and its unacceptable pulmonary toxicity.

High-grade glioma in children under 5 years of age: a chemotherapy only approach with the BBSFOP protocol

The aim of this study was to evaluate a chemotherapy strategy that avoids radiotherapy in first-line treatment of young children with high-grade glioma. A total of 21 children under 5 years of age received the BBSFOP protocol, comprising seven cycles of three drug pairs (carboplatin/procarbazine, cisplatin/etoposide and vincristine/cyclophosphamide) administered over a 16 month period. Radiotherapy was performed in case of recurrence/progression. Median age at diagnosis was 23 months. Histology was classified as World Health Organisation (WHO) grade III in 13 and grade IV in 8. Of the 13 children with a residual tumour, chemotherapy induced 2 partial responses (PR), 1 minor response (MR) and 1 stable disease (SD) with no recurrent disease. Five-year progression-free survival was 35% and 5-year overall survival was 59%, with a median follow-up of 5.2 years. At the last update, 12 children were alive (10 without radiotherapy). In conclusion, this study shows that an adjuvant chemotherapy first approach is safe and allows radiotherapy to be avoided in selected children.

Topotecan as a radiosensitizer in the treatment of children with malignant diffuse brainstem gliomas: results of a French Society of Paediatric Oncology Phase II Study

BACKGROUND

The current Phase II study was conducted to evaluate the survival and toxicity observed in children with newly diagnosed brainstem gliomas who were treated with the daily radiotherapy with topotecan used as a radiosensitizer.

METHODS

Eligible patients were those ages 3-18 years with previously untreated tumors arising in the pons diagnosed within the previous 6 months. Histologic confirmation was not mandatory provided that the clinical and magnetic resonance imaging findings were typical for a diffusely infiltrating brainstem lesion. Treatment was comprised of a 6-week course of topotecan administered intravenously at a dose of 0.4 mg/m(2)/day over 30 minutes within 1 hour before irradiation. Radiotherapy was comprised of a once-daily treatment of 1.8 grays (Gy) per fraction to a total dose of 54 Gy.

RESULTS

Thirty-two patients were included in the current study between August 2000 and October 2002. All patients completed the combined treatment in accordance with the treatment design. Only partial responses were observed, occurring in 40% of the patients. The 9-month and 12-month survival rates were 34.4% +/- 8% and 25.5% +/- 8%, respectively. The median duration of survival for these 32 patients was 8.3 months. An intratumoral cystic/necrotic change was observed in five patients, with clinical impairment noted in two patients. One intratumoral hemorrhage occurred during radiotherapy, and was associated with transitory neurologic impairment.

CONCLUSIONS

The findings of the current study regarding newly diagnosed brainstem glioma patients treated with topotecan given as a radiosensitizing agent did not reproduce the encouraging results obtained in preclinical studies. Therefore, the concomitant combination of topotecan and radiotherapy at this schedule and these doses cannot be recommended for the treatment of patients with brainstem gliomas.

Childhood ependymoma: a systematic review of treatment options and strategies

Childhood intracranial ependymoma have a dismal prognosis, especially in young children and when a gross total resection cannot be performed. Even in the absence of a radiologically proven residuum, around two-thirds of these young children will have a recurrence. Adjuvant therapy is therefore necessary for most, if not all, patients. Despite some indication that benign ependymoma (WHO grade II) could show a better outcome, histology cannot be used at present to stratify treatment protocols.Craniospinal irradiation combined with posterior fossa boost has deleterious adverse effects on cognition. Consequently, pediatric oncology teams have, firstly, tried to use chemotherapy to delay or avoid irradiation, and secondly, progressively reduced irradiation fields to the tumor bed without altering the prognosis. Cisplatin, at a dose of 120 mg/m(2) (cumulated response rate of 34% [95% CI 19-54%]) is the only single agent that has reproducibly shown some efficacy in ependymoma. Despite some combinations showing efficacy in the adjuvant setting, childhood intracranial ependymomas can, in general, be considered as chemoresistant. The overexpression of the multidrug resistance-1 gene and the 06-methylguanine-DNA methyltransferase have been implicated as possible mechanisms for this phenomenon. As the use of chemotherapy with current agents is questionable, phase II studies with new agents and combinations are necessary. Since the main problem of this disease is local relapse, it may not be necessary to irradiate the whole posterior fossa. However, local control of the disease by irradiation has to be improved. In this respect, hyperfractionation or radiosensitizers may be valuable therapeutic options. The treatment of children with ependymoma is a challenge for all caregivers. There is no doubt that any possible improvement in the management of this rare tumor will only be the result of well designed cooperative trials.