Review of Cerebral Radiotherapy-Induced Vasculopathy in Pediatric and Adult Patients

Radiation therapy for childhood-onset craniopharyngioma: systematic review and meta-analysis

BACKGROUND

Craniopharyngioma (CP), a benign tumor originating from remnants of Rathke's pouch in the sellar region, accounts for approximately 30% of all cases of craniopharyngioma. Radiation therapy has been used to treat CP patients for decades; however, there is still a lack of systematic reviews on the long-term tumor control outcomes in pediatric CP patients treated with external radiation therapy.

METHODS

We conducted a comprehensive search of multiple databases for studies on the tumor progression rates of childhood-onset CP(COCP) patients who received external radiotherapy. We also recorded morbidities related to hypopituitarism and vasculopathy. A meta-analysis was performed to calculate the pooled incidence rates. Meta-regression was applied to explore potential sources of heterogeneity in the tumor progression rates.

RESULTS

A total of 22 studies were included after screening and eligibility assessment in accordance with PRISMA guidelines. The median (mean) follow-up period ranged from 2 to 14.9 years. The pooled overall tumor progression rate was 0.10 (95% CI 0.07-0.15). The recurrence rates were 0.14 (95% CI 0.09-0.19) for photon therapy and 0.04 (95% CI 0.01-0.07) for proton therapy. Meta-regression indicated that none of the following underlying risk factors significantly affected the heterogeneity of the recurrence rate: radiation modality (photon vs. proton), median (mean) follow-up duration, or the proportion of patients who did not undergo surgical resection. The pooled incidence of growth hormone deficiency (GHD), thyroid hormone deficiency (THD), adrenocorticotropic hormone deficiency (ACTHD), gonadotropin-releasing hormone deficiency (GnRHD), and diabetes insipidus (DI) were 0.81 (95% CI 0.70-0.90), 0.88 (95% CI 0.79-0.95), 0.69 (95% CI 0.52-0.85), 0.43 (95% CI 0.38-0.49), and 0.56 (95% CI 0.33-0.78), respectively. The pooled morbidity rate for vasculopathy was 0.06 (95% CI 0.04-0.09), with similar rates observed for both photon and proton therapy.

CONCLUSION

Radiotherapy is a suitable adjuvant or alternative treatment method for childhood CP patients. However, patients inevitably face significant long-term treatment-related complications.

Evaluating the safety and efficacy of proton radiotherapy for intracranial pediatric ependymomas: A single-arm meta-analysis

BACKGROUND

Ependymomas account for 6% to 10% of childhood central nervous system tumors. This study aimed to evaluate the safety and efficacy of proton radiotherapy in intracranial ependymoma patients.

METHODS

We performed a systematic review and single-arm meta-analysis. We searched Medline, Embase, Cochrane, and Web of Science for eligible trials. Random-effects model was used to calculate the risk ratios (RRs), with 95% confidence intervals (CIs). Statistical analyses were performed using RStudio version 4.2.3.

RESULTS

Ten cohorts comprising 908 patients with ependymoma were included. The patient population had an average age of 3.5 years, and 53.4 % were male. In terms of proportion, nine outcomes were analyzed: 3-year Progression-Free Survival (PFS; Proportion = 0.63; 95 % CI [0.40-0.87]; I2 = 95 %), 5-year Local Control (LC; Proportion = 0.79; 95 % CI [0.69-0.90]; I2 = 85 %), 5-year Event-Free Survival (EFS; Proportion = 0.65; 95 % CI [0.52-0.78]; I2 = 95 %), 5-year Overall Survival (OS; Proportion = 0.83; 95 % CI [0.77-0.90]; I2 = 82 %), 2-year OS (Proportion = 0.91; 95 % CI [0.88-0.94]; I2 = 0 %), 3-year OS (Proportion = 0.92; 95 % CI [0.89;0.95]; I2 = 43 %). Additionally, neurological (Proportion = 0.17; 95 % CI [0.07-0.27]; I2 = 97 %), dermatological (Proportion = 0.20; 95 % CI [0.00-0.44]; I2 = 82 %), and brainstem complications (Proportion = 0.03; 95 % CI [0.01-0.04]; I2 = 31 %) were investigated.

CONCLUSION

While proton radiotherapy appears safe and effective based on current data, these results should be approached cautiously, as broad confidence intervals in some adverse event rates suggest variability in outcomes.

Mechanisms of radiation-induced tissue damage and response

Radiation-induced tissue injury (RITI) is the most common complication in clinical tumor radiotherapy. Due to the heterogeneity in the response of different tissues to radiation (IR), radiotherapy will cause different types and degrees of RITI, which greatly limits the clinical application of radiotherapy. Efforts are continuously ongoing to elucidate the molecular mechanism of RITI and develop corresponding prevention and treatment drugs for RITI. Single-cell sequencing (Sc-seq) has emerged as a powerful tool in uncovering the molecular mechanisms of RITI and for identifying potential prevention targets by enhancing our understanding of the complex intercellular relationships, facilitating the identification of novel cell phenotypes, and allowing for the assessment of cell heterogeneity and spatiotemporal developmental trajectories. Based on a comprehensive review of the molecular mechanisms of RITI, we analyzed the molecular mechanisms and regulatory networks of different types of RITI in combination with Sc-seq and summarized the targeted intervention pathways and therapeutic drugs for RITI. Deciphering the diverse mechanisms underlying RITI can shed light on its pathogenesis and unveil new therapeutic avenues to potentially facilitate the repair or regeneration of currently irreversible RITI. Furthermore, we discuss how personalized therapeutic strategies based on Sc-seq offer clinical promise in mitigating RITI.

A Case Report on Radiation-Induced Cerebral Vasculopathy in a Long-Term Survivor of Childhood Medulloblastoma

This case report discusses a patient diagnosed with radiation-induced cerebral vasculopathy who presented after cerebral irradiation of metastatic medulloblastoma to raise awareness of radiation-induced cerebral vasculopathy. Because radiation therapy has revolutionized treatment for children with brain cancers, radiation-induced vasculopathy is becoming ever more prominent, and its recognition is crucial to implementing early treatment strategies to improve patient outcomes. Currently, medical management is poorly defined, largely unexamined, and poorly studied. Because the clinical features of this disease are nonspecific, radiation-induced cerebral vasculopathy remains a diagnosis of exclusion and an essential addition to the differential diagnosis. Discussion regarding standardized treatment, screening, and guidelines is necessary to improve treatment and survival.

Endothelial marker profiles in cerebral radiation-induced vasculopathy: A comparative immunohistochemical analysis

Radiation therapy results in radiation-induced vasculopathy, characterized by alterations in the vascular architecture stemming from radiation exposure. The exact molecular pathways and associated pathologies of this condition have yet to be comprehensively understood. This study aimed to identify specific markers' roles in cerebral vascular endothelial injury pathogenesis after radiosurgery and explore their unique expression patterns in diverse pathologies post-stereotactic radiosurgery. A retrospective cohort study was conducted to assess the expression profiles of endothelial markers via immunohistochemical analysis in 25 adult patients (13 males and 12 females) who had undergone neurosurgical resection for various central nervous system pathologies following stereotactic radiosurgery or radiotherapy from 2001 to 2015. Our findings revealed strong immunohistochemical expression of ICAM-1 and E-selectin across various disease states, while MMP-9, PAI-1, and eNOS exhibited moderate expression levels. In contrast, VCAM-1 and P-Selectin had the weakest expression across all groups. Notably, while individual markers showed significant variations in expression levels when comparing different diseases (P < .001), no substantial differences were found in the overall immunohistochemical expression patterns across the 5 distinct pathologies studied (P = .407, via 2-way ANOVA). Despite the varied long-term effects of radiotherapy on the vascular endothelium, a common thread of inflammation runs through the pathology of these conditions. The distinct patterns of marker expression identified in our study suggest that different markers play unique roles in the development of radiation-induced vasculopathy. These findings offer insights that could lead to the development of novel preventive strategies and treatments.