Proffered paper session: CNS tumours

Dr Pieterjan Vanclooster, resident in medical oncology at Antwerp University Hospital and PhD researcher at the Centre for Oncological Research, presented his selection of daily highlights from the proffered papers session on CNS tumours.

The first study discussed was the BREAKB5 trial, a non-randomised phase II investigation evaluating treatment strategies for patients with active or inactive brain metastases originating from NSCLC lacking oncogenic driver mutations. This trial included patients receiving first-line therapy for metastatic disease, treated with carboplatin and nab-paclitaxel for two cycles in combination with nivolumab and ipilimumab, followed by maintenance immunotherapy. Bevacizumab was added as an anti-angiogenic agent to mitigate perilesional oedema and neurological symptoms. The trial reported favourable results, demonstrating improved PFS and intracranial response rates. However, given the absence of a control arm and the availability of comparable regimens—such as platinum doublet chemotherapy combined with immunotherapy—the findings are not considered practice-changing. The non-randomised design precludes direct comparison, and further confirmatory studies are required to determine clinical relevance.

The second study presented was a randomised open-label Chinese trial investigating the management of skull base chordoma and chondrosarcoma, both of which are radioresistant malignancies. Patients were randomised to receive either proton or carbon ion radiotherapy. Conventional photon-based therapy remains largely ineffective for these tumour types due to their intrinsic resistance, making particle therapy a rational approach. The results demonstrated a statistically significant improvement in local control, local PFS and OS with carbon ion therapy compared to proton therapy. These data suggest a potential practice-changing implication, supporting the integration of carbon ion radiotherapy as a preferred option for these rare but challenging tumours, complementing or possibly replacing current proton-based approaches in specialised centres.

The final study discussed was another Chinese trial evaluating chlorogenic acid, a plant-derived compound administered intramuscularly, versus lomustine, the current standard second-line therapy for recurrent GBM. Although the investigators reported superior outcomes with chlorogenic acid, significant methodological uncertainties were identified. Key details regarding randomisation procedures, trial powering, and baseline characteristics were insufficiently described. Furthermore, the survival outcomes reported were uncharacteristically long for a recurrent GBM population, raising concerns about patient selection and data validity. Due to these substantial methodological limitations, the trial’s credibility and conclusions are questionable. It cannot be considered a positive study, and its findings should not influence current clinical practice until independently validated.