Safety and efficacy of surgical treatment for brainstem hemangioblastoma: a meta-analysis

Neurological applications of belzutifan in von Hippel-Lindau disease

Von Hippel-Lindau (VHL) disease is a tumor predisposition syndrome caused by mutations in the VHL gene that presents with visceral neoplasms and growths, including clear cell renal cell carcinoma, and central nervous system manifestations, such as hemangioblastomas of the brain and spine. The pathophysiology involves dysregulation of oxygen sensing caused by the inability to degrade HIFα, leading to the overactivation of hypoxic pathways. Hemangioblastomas are the most common tumors in patients with VHL and cause significant morbidity. Until recently, there were no systemic therapies available for patients that could effectively reduce the size of these lesions. Belzutifan, the first approved HIF-2α inhibitor, has demonstrated benefit in VHL-associated tumors, with a 30% response rate in hemangioblastomas and ~30%-50% reduction in their sizes over the course of treatment. Anemia is the most prominent adverse effect, affecting 76%-90% of participants and sometimes requiring dose reduction or transfusion. Other significant adverse events include hypoxia and fatigue. Overall, belzutifan is well tolerated; however, long-term data on dosing regimens, safety, and fertility are not yet available. Belzutifan holds promise for the treatment of neurological manifestations of VHL and its utility may influence the clinical management paradigms for this patient population.

Hemangioblastomas and Other Vascular Origating Tumors of Brain or Spinal Cord

Hemangioblastomas (HBs) are highly vascularized, slow-growing, rare benign tumors (WHO grade I). They account for about 2% of intracranial neoplasms; however, they are the most common primary cerebellar tumors in adults. Another frequent seat is the spinal cord (2-10% of primary spinal cord tumors). HBs are constituted by stromal and capillary vascular cells; macroscopically, HBs appear as nodular tumors, with or without cystic components. Although most of the HBs are sporadic (57-75%), they represent a particular component of von Hippel-Lindau disease (VHL), an autosomal dominant syndrome with high penetrance, due to a germline pathogenic mutation in the VHL gene, which is a tumor suppressor with chromosomal location on the short arm of chromosome three. VHL disease determines a variety of malignant and benign tumors, most frequently HBs, renal cell carcinomas, pheochromocytomas/paragangliomas, pancreatic neuroendocrine tumors, and endolymphatic sac tumors. Up to 20% of cases are due to de novo pathogenic variants without a family history. Many epidemiologic details of these tumors, especially the sporadic forms, are not well known. The median age of patients with sporadic HBS is about 40 years. More than two-third of VHL patients develop one or more central nervous system HBs during their lifetime; in case of VHL, patients at first diagnosis are usually younger than the patients with sporadic tumors. The most common presenting signs and symptoms are related to increased intracranial pressure, cerebellar signs, or spinal cord alterations in case of spinal involvement. Magnetic resonance imaging is the gold standard for the diagnosis, assessment, and follow-up of HBs, both sporadic and syndrome-related; angiography is rarely performed because the diagnosis is easily obtained with magnetic resonance. However, the diagnosis of an asymptomatic lesion does not automatically result in therapeutic actions, as the risks of treatment and the onset of possible neurological deficit need to be balanced, considering that HBs may remain asymptomatic and have a static or slow-growing behavior. In such cases, regular follow-up can represent a valid therapeutic option until the patients remain asymptomatic. There are no actual pharmacological therapies that are demonstrated to be effective for HBs. Surgery represents the primary therapeutic approach for these tumors. Observation or radiotherapy also plays a role in the long-term management of patients harboring HBs, especially in VHL; in few selected cases, endovascular treatment has been suggested before surgical removal. This chapter presents a systematic overview of epidemiology, clinical appearance, histopathological and neuroradiological characteristics of central nervous system HBs. Moreover, the genetic and molecular biology of sporadic and VHL HBS deserves special attention. Furthermore, we will describe all the available therapeutic options, along with the follow-up management. Finally, we will briefly report other vascular originating tumors as hemangioendotheliomas, hemangiomas, or angiosarcomas.

Bibliometric Analysis of the 100 Most Influential Hemangioblastoma Research Articles Illustrates Progress in Clinical Management and Room for Growth in Targeted Therapies

OBJECTIVE

This bibliometric analysis aims to identify the most impactful articles on hemangioblastoma (HB) and evaluate the trajectory of academic literature in the field.

METHODS

The authors performed a title search using the Web of Science database, with ("hemangioblastoma" OR "haemangioblastoma") as a search query. The top 100 cited articles from the years 1900-2020 were sorted by the descending order of the total citation count. The following variables were assessed for each article: title, first author name and institution, publication year, country of origin, citation count, citations per year, and journal impact factor.

RESULTS

The query yielded 1918 articles related to the topic of HB that were published between the years 1900 and 2020 in 42 unique journals. The most prolific decade of publication was the 2000s (35%), followed by the 1990s (33%) and the 1980s (11%). The average citation count was 88.3 (range, 47-426), and the mean number of citations per year was 3.74 (range, 0.660-17.8).

CONCLUSIONS

This is the first bibliometric analysis to evaluate the most influential HB publications. Though a majority of HBs are sporadic, these results suggest a research focus on von Hippel-Lindau-associated tumors. Despite established evidence for the potential to control HB growth with vascular endothelial growth factor inhibition, there are no known clinical trials underway for this investigation. There is a need for consistent treatment guidelines for asymptomatic HBs, as resection can prevent the development of neurological deficits. An improved understanding of the etiology of these neoplasms could promote the development of novel diagnostic and treatment methods.

Treatment Strategy for Giant Solid Hemangioblastomas in the Posterior Fossa: A Retrospective Review of 13 Consecutive Cases

OBJECTIVE

To analyze radiologic characteristics, treatment strategy, and treatment outcomes of posterior fossa giant solid hemangioblastomas (GSHBs; ≥4 cm in maximum diameter).

METHODS

We performed a retrospective study of 13 consecutive patients (9 male and 4 female patients; mean age, 57.5 ± 13.3 years; range, 24-76 years) with GSHB who underwent surgical resection at a single institution between 2002 and 2018. The median follow-up was 33 months (range, 12-120 months). For each patient, neuroimaging findings, operative record, and treatment outcome were reviewed.

RESULTS

Seven tumors (53.8%) were located within cerebellar hemispheres, 4 (30.8%) in proximity to the brainstem, 1 (7.7%) within the cerebellar vermis, and 1 (7.7%) in the cerebellopontine angle. The mean maximum diameter was 4.8 ± 0.8 cm (range, 4.0-6.7 cm). Gross total resection was achieved in 11 patients (84.6%), and near-total resection in 2 patients (15.4%). Surgical complications occurred in 5 patients (38.5%); persistent neurologic deficits occurred in 2 patients (15.4%). Estimated progression-free survival after surgery was 92.3%, 80.8%, and 80.8% at 1, 5, and 10 years, respectively, whereas the estimated 1-year, 5-year, and 10-year overall survival was 100%, 90%, and 90%, respectively.

CONCLUSIONS

GSHBs are surgically challenging. The current study shows that favorable outcome can be achieved for GSHBs in the cerebellar hemispheres and vermis. For those involving the brainstem, planned near-total resection or subtotal resection in a piecemeal fashion can be attempted if en bloc resection is judged to be infeasible, and further intervention can be considered as needed.

Incidence, Prognostic Factors and Survival for Hemangioblastoma of the Central Nervous System: Analysis Based on the Surveillance, Epidemiology, and End Results Database

Background

Hemangioblastomas are uncommon, benign neoplasms of the central nervous system (CNS). This study aims to evaluate the incidence, demographics, clinical characteristics, and prognosis of CNS hemangioblastomas using the data from the Surveillance, Epidemiology, and End Results (SEER) Program.

Methods

Univariate and multivariate analyses using the Cox proportional hazards model were employed to identify prognostic factors of overall survival. The Kaplan-Meier method was utilized to evaluate overall survival distribution by treatment modality. A nomogram was further built to predict survival at 3 and 5 years.

Results

The overall incidence rate of CNS hemangioblastomas was 0.141 per 100,000 person-years. Through univariate analysis and multivariate analyses, age between 60 and 79 years (HR = 3.697, p < 0.001), age greater than 80 years (HR = 12.318, p < 0.001), African American race (HR = 1.857, p = 0.003), multiple tumors (HR = 1.715, p < 0.001), and prior surgery (HR = 0.638, p = 0.013) were significantly associated with overall survival. Patients receiving surgery alone had better overall survival compared with patients receiving no treatment (p = 0.008) and patients receiving both surgery and radiotherapy (p = 0.002). The calibration plots demonstrated an excellent agreement between nomogram-predicted and actual survival.

Conclusion

In conclusion, age, race, tumor location, number of tumors, and prior surgery are prognostic factors for survival. Surgery was the most common modality and was suggested as an effective and optimal treatment. The proposed nomogram can predict the prognosis of patients with CNS hemangioblastomas and help clinicians in making decisions.