Pediatric diffuse midline glioma: Understanding the mechanisms and assessing the next generation of personalized therapeutics

Deep Learning Auto-segmentation of Diffuse Midline Glioma on Multimodal Magnetic Resonance Images

Diffuse midline glioma (DMG) H3 K27M-altered is a rare pediatric brainstem cancer with poor prognosis. To advance the development of predictive models to gain a deeper understanding of DMG, there is a crucial need for seamlessly integrating automatic and highly accurate tumor segmentation techniques. There is only one method that tries to solve this task in this cancer; for that reason, this study develops a modified CNN-based 3D-Unet tool to automatically segment DMG in an accurate way in magnetic resonance (MR) images. The dataset consisted of 52 DMG patients and 70 images, each with T1W and T2W or FLAIR images. Three different datasets were created: T1W images, T2W or FLAIR images, and a combined set of T1W and T2W/FLAIR images. Denoising, bias field correction, spatial resampling, and normalization were applied as preprocessing steps to the MR images. Patching techniques were also used to enlarge the dataset size. For tumor segmentation, a 3D U-Net architecture with residual blocks was used. The best results were obtained for the dataset composed of all T1W and T2W/FLAIR images, reaching an average Dice Similarity Coefficient (DSC) of 0.883 on the test dataset. These results are comparable to other brain tumor segmentation models and to state-of-the-art results in DMG segmentation using fewer sequences. Our results demonstrate the effectiveness of the proposed 3D U-Net architecture for DMG tumor segmentation. This advancement holds potential for enhancing the precision of diagnostic and predictive models in the context of this challenging pediatric cancer.

Chimeric antigen receptor-macrophages: Emerging next-generation cell therapy for brain cancer

Adoptive cell-based therapy utilizing chimeric antigen receptor (CAR)-T technology holds promise in the field of neuro-oncology. Significant progress has been made in enhancing both the efficacy and safety of CAR-T-cell therapies. However, challenges such as the multifaceted immunosuppressive impact of the tumor microenvironment and insufficient CAR-T-cell infiltration into brain tumor sites remain a major hurdles. Emerging novel approaches utilizing CAR-macrophages (CAR-MACs) show potent results for brain tumor immunotherapy. CAR-MACs localize to tumor sites more readily, increase immune cell infiltrates, and demonstrate high antitumor efficacy by effectively eliminating tumor cells through mechanisms such as phagocytosis or efferocytosis. This review discusses the current advancements in CAR-MAC cell therapies for brain cancer, followed by an overview of research on manufacturing CAR-MACs for clinical application. We further highlight the potential future applications of CAR-MACs in combinatory therapies in the treatment of brain tumors.

Long-term survival after cordectomy in a case of spinal cord diffuse midline glioma, H3K27-altered: illustrative case

BACKGROUND

Spinal cord diffuse midline glioma, H3K27-altered, is an extremely rare entity with a poor prognosis. However, its optimal treatment remains poorly defined. Although cordectomy was introduced in the early 20th century, its efficacy has been questioned and shrouded behind the scenes.

OBSERVATIONS

A 76-year-old male with recent-onset paraparesis of the lower extremities and paresthesia presented to our outpatient clinic. Magnetic resonance imaging revealed an intra-axial spinal cord tumor extending from T12 to L2. The patient underwent laminectomy and partial tumor resection, and the surgical specimen was histologically diagnosed as a diffuse midline glioma, H3K27-altered. Although standard chemoradiotherapy was implemented, the patient experienced local tumor recurrence 2 years later and underwent cordectomy at T9. The patient was alive at the 4-year follow-up after cordectomy without tumor recurrence. According to the literature, patients with lesions in the lower thoracic cord below T8 achieved a longer survival than those with lesions in the upper thoracic cord above T5.

LESSONS

Cordectomy benefits selected cases of high-grade spinal cord gliomas. Maximal prevention of cerebrospinal fluid dissemination by tumor cells is indisputably important, and tumors located below the lower thoracic spine may be the key to success in establishing a long-term prognosis after cordectomy.

Clinical outcomes of stereotactic biopsy on children with pontine diffuse midline glioma

INTRODUCTION

Diffuse midline glioma (DMG) of the pons occurs in pediatric patients and carries a dismal prognosis. Biopsy is not necessary for diagnosis but provides information, particularly H3K27M status, with prognostic implications. Additionally, biopsy information may open therapeutic options such as clinical trials that require mutation status. Therefore, we sought to assess the safety of surgical biopsy in DMG patients as well as its potential impact on clinical course.

METHODS

Retrospective analysis of patients who were radiographically and clinically diagnosed with pontine DMG in the last 5 years was performed. We assessed demographic, clinical, radiographic, surgical, and follow-up data.

RESULTS

25 patients were included; 18 (72%) underwent biopsy while 7 (28%) declined. 12 biopsies (67%) were performed with robotic arm and 5 (27%) with frameless stereotaxy. Three biopsied patients (17%) experienced new post-operative neurologic deficits (1 facial palsy, 1 VI nerve palsy and 1 ataxia) that all resolved at 2-week follow-up. All biopsies yielded diagnostic tissue. Fourteen patients (78%) had H3K27M mutation. Median OS for H3K27M patients was 10 months compared to 11 months in the wild-type patients (p = 0.30, log-rank test). Median OS for patients enrolled in clinical trials was 12 months compared to 8 months for non-trial patients (p = 0.076).

CONCLUSION

In our series, stereotactic pontine DMG biopsies did not carry any permanent deficit or complication and yielded diagnostic tissue in all patients. Similar post-operative course was observed in both robot-assisted and frameless stereotactic approaches. There was no significant difference in survival based on mutation status or clinical trial enrollment.