Potential Therapeutic Role for Aspirin in the Management of Sporadic Vestibular Schwannoma
In patients with sporadic vestibular schwannoma, aspirin may be of benefit in minimizing tumor growth, according to the results of a retrospective study presented by Kandathil et al in Otology and Neurotology. This finding may eliminate the need for invasive therapy and may complement existing modalities.
Study Details
The investigators previously identified nuclear factor kappa B (NF-κB) to be a modulator in the tumorigenesis of sporadic vestibular schwannoma. Knowing that, they decided to examine aspirin, a known inhibitor of NF-κB, for its potential therapeutic benefits in sporadic vestibular schwannoma.
The study encompassed 689 patients with sporadic vestibular schwannoma. Patients were divided into two groups: those taking aspirin and those not taking aspirin. All subjects in the study had at least one comorbidity that warranted the use of long-term aspirin therapy.
The size of the tumors was measured from three viewpoints: anteroposterior, superoinferior, and transverse. The tumors were considered to be growing if any of the previously mentioned viewpoints via MRI scans indicated enlargement in size. The rate of tumor growth was indicated in millimeters per year. Two study outcomes were projected: any change in tumor size and annual change in the size of the sporadic vestibular schwannoma.
Five distinct analyses were performed. One focused on the difference between aspirin use and no aspirin use regarding the growth of sporadic vestibular schwannoma. A second analysis attempted to determine whether age and sex were factors among users and nonusers of aspirin. A third analysis calculated odds ratios (OR) and 95% confidence interval (CI). The average tumor growth rate between aspirin users and nonusers was determined in a fourth analysis using a t test. Finally, a fifth analysis compared the size of tumors at diagnosis in aspirin users compared with nonusers.
Better Outcomes in Aspirin Users
From a retrospective viewpoint, patients with sporadic vestibular schwannoma who were aspirin users had less tumor growth than patients who were nonaspirin users. Of the patients whose tumors were followed by serial MRI scans, 23% were aspirin users and 77% were nonusers. In patients who experienced a growth in tumor size (54% of all patients), 18% were aspirin users. In patients who experienced no growth in tumor size (46% of all patients), 30% were aspirin users. This difference in tumor growth between aspirin users and nonusers was statistically significant (P = .0076, OR = 0.50, 95% CI = 0.29–0.85). There was also a significant difference in sporadic vestibular schwannoma growth vs no growth between aspirin users and nonusers on age-adjusted analysis (P = .0061, OR = 0.47, 95% CI = 0.27–0.83).
As for the results of the analysis regarding the growth of the tumor from initial diagnosis, the mean initial size was 10.3 ± 0.74 mm for aspirin users and 10.5 ± 0.45 mm for nonusers. This did not represent a significant difference between the two groups (P = .89).
As for the analysis of tumor growth over time in relationship to continued aspirin use, there was less tumor growth among aspirin users (0.865 ± 0.18 mm/yr) than nonusers (1.23 ± 0.12 mm/yr). This did not represent a significant difference between the two groups (P = .11).
Clinical Implications
For the first time, investigators demonstrated there was a correlation between aspirin use and the growth rate of sporadic vestibular schwannoma. For still unknown reasons, it appears that sporadic vestibular schwannoma is responsive to targets of aspirin signaling, such as cyclooxygenase-2 and NF-κB. Future research may determine whether other types of tumors are as responsive to aspirin as these schwannomas. The potential use of aspirin as an anticancer agent has many benefits, including its ease of use, a rather favorable side-effect profile, and a limited association with the development of other diseases, they noted.
In a statement, lead author Konstantina Stankovic, MD, PhD, of the Massachusetts Eye and Ear Infirmary, Boston, remarked, “Currently, there are no FDA-approved drug therapies to treat these tumors, which are the most common tumors of the cerebellopontine angle and the fourth most common intracranial tumors.… Our results suggest a potential therapeutic role of aspirin in inhibiting vestibular schwannoma growth.”
Dr. Stankovic is the corresponding author of the article in Otology & Neurotology.
This study was supported by the National Institute on Deafness and Other Communication Disorders and the Bertarelli Foundation. The authors disclosed no potential conflicts of interest.
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