Spinal Dissemination of Intracranial Glioblastoma in Bevacizumab Era: a Potential Bevacizumab-induced Mechanism

Leptomeningeal Spread in Glioblastoma: Diagnostic and Therapeutic Challenges

BACKGROUND

Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor. Leptomeningeal spread (LMS) is a severe complication of GBM, raising diagnostic and therapeutic challenges in clinical routine.

METHODS

We performed a review of the literature focused on LMS in GBM. MEDLINE and EMBASE databases were queried from 1989 to 2019 for articles describing diagnosis and therapeutic options in GBM LMS, as well as risk factors and pathogenic mechanisms.

RESULTS

We retrieved 155 articles, including retrospective series, case reports, and early phase clinical trials, as well as preclinical studies. These articles confirmed that LMS in GBM remains (a) a diagnostic challenge with cytological proof of LMS obtained in only 35% of cases and (b) a therapeutic challenge with a median overall survival below 2 months with best supportive care alone. For patients faced with suggestive clinical symptoms, whole neuroaxis magnetic resonance imaging and cerebrospinal fluid analysis are both recommended. Liquid biopsies are under investigation and may help prompt a reliable diagnosis. Based on the literature, a multimodal and personalized therapeutic approach of LMS, including surgery, radiotherapy, systemic cytotoxic chemotherapy, and intrathecal chemotherapies, may provide benefits to selected patients. Interestingly, molecular targeted therapies appear promising in case of actionable molecular target and should be considered.

CONCLUSION

As the prognosis of glioblastoma is improving over time, LMS becomes a more common complication. Our review highlights the need for translational studies and clinical trials dedicated to this challenging condition in order to improve diagnostic and therapeutic strategies.

IMPLICATIONS FOR PRACTICE

This review summarizes the diagnostic tools and applied treatments for leptomeningeal spread, a complication of glioblastoma, as well as their outcomes. The importance of exhaustive molecular testing for molecular targeted therapies is discussed. New diagnostic and therapeutic strategies are outlined, and the need for translational studies and clinical trials dedicated to this challenging condition is highlighted.

Diagnosis, treatment, and survival in spinal dissemination of primary intracranial glioblastoma: systematic literature review

OBJECTIVE

Spinal metastases from primary intracranial glioblastoma (GBM) are infrequently reported, and the disease has yet to be well characterized. A more accurate description of its clinical presentation and patient survival may improve understanding of this pathology, guide patient care, and advocate for increased inclusion in GBM research. The authors sought to describe the clinical presentation, treatment patterns, and survival in patients with drop metastases secondary to primary intracranial GBM.

METHODS

A systematic review was performed using the PRISMA guidelines. PubMed/MEDLINE, Scopus, Web of Science, and Cochrane databases were queried for abstracts that included patients with primary intracranial GBM and metastases to the spinal axis. Descriptive statistics were used to evaluate characteristics of the primary brain lesion, timing of spinal metastases, clinical symptoms, anatomical location of the metastases, and survival and treatment parameters. Kaplan-Meier analysis and log-rank analysis of the survival curves were performed for selected subgroups.

RESULTS

Of 1225 abstracts that resulted from the search, 51 articles were selected, yielding 86 subjects. The patients' mean age was 46.78 years and 59.74% were male. The most common symptom was lumbago or cervicalgia (90.24%), and this was followed by paraparesis (86.00%). The actuarial median survival after the detection of spinal metastases was 2.8 months and the mean survival was 2.72 months (95% CI 2.59-4.85), with a 1-year cumulative survival probability of 2.7% (95% CI 0.51%-8.33%). A diagnosis of leptomeningeal disease, present in 53.54% of the patients, was correlated, and significantly worse survival was on log-rank analysis in patients with leptomeningeal disease (p = 0.0046; median survival 2.5 months [95% CI 2-3] vs 4.0 months [95% CI 2-6]).

CONCLUSIONS

This study established baseline characteristics of GBMs metastatic to the spinal axis. The prognosis is poor, though these results will provide patients and clinicians with more accurate survival estimates. The quality of studies reporting on this disease pathology is still limited. There is significant need for improved reporting methods for spinal metastases, either through enrollment of these patients in clinical trials or through increased granularity of coding for metastatic central nervous system diseases in cancer databases.

Efficacy of bevacizumab therapy in recurrent malignant gliomas in relation to the prior recurrence pattern or tumor location

Although promising preliminary results have been widely observed with bevacizumab for recurrent malignant gliomas, many unanswered questions remain to be resolved to achieve an optimal outcome. No predictive biomarkers of a survival benefit from bevacizumab have been established, and no consensus exists about the response or survival benefit regarding the prior recurrence pattern or tumor location. Here we retrospectively analyzed the clinical benefit from bevacizumab for recurrent malignant gliomas in relation to the prior recurrence pattern or tumor location. Thirty-one consecutive patients with recurrent malignant gliomas who were treated with bevacizumab were investigated. The treatment response and survival benefit from bevacizumab were analyzed in association with age, sex, Karnofsky performance status, prior pathological diagnosis, prior recurrence pattern, primary location of tumor, recurrence status, and expression of angiogenic and hypoxic markers. The group with leptomeningeal dissemination had a significantly shorter median overall survival with bevacizumab (OS_Bev) (6.0months, 95% confidence interval (CI) 1.4-10.7) compared to those in the local/distant group (11.8months, 95% CI 6.1-17.4). The median OS_Bev of the infratentorial tumor group and supratentorial tumor group were 9.2months (95% CI 5.0-13.4) and 10.4months (95% CI 6.6-14.3), respectively. With multivariate analysis, the prior recurrence pattern was the only independent prognostic factor of OS_Bev. Patients with leptomeningeal dissemination of recurrent malignant glioma experienced minimal benefit from bevacizumab. Therefore, in the context of cost effectiveness, bevacizumab is not recommended for patients with leptomeningeal dissemination.