Cost of Vestibular Schwannoma Treatment: A Systematic Review and Meta-Analysis

Keywords

vestibular schwannoma - acoustic neuromas - treatment cost - literature review - surgery vs stereotactic radiosurgery

Introduction

Vestibular schwannomas (VS), also known as “acoustic neuromas,” are benign nerve sheath tumors representing 8 to 10% of primary intracranial tumors.[1] Management of VS is largely separated into four categories: (1) microsurgical resection, (2) stereotactic radiosurgery (SRS), (3) observation, and (4) a combination of the above.[2] [3] [4] The variability of these tumors' natural history makes optimal treatment unpredictable and case specific.[5] [6] [7] A lack of randomized clinical trials often forces the multidisciplinary team managing VS to rely largely on retrospective evidence and institutional experience based on the patient's symptoms, age, and preference as well as tumor size and growth pattern.[8]

In modern medical practices, cost of treatment is an increasingly recognized factor in the allocation of high quality and equitable care. As recently as 2020, United States (US) healthcare spending has reached $4.3 trillion and accounts for 18.4% of the nation's gross domestic product.[9] Given the complexity of treatment options surrounding VS, understanding costs associated with each treatment option is imperative for both the patient and the economic viability of healthcare institutions. There are few studies that discuss the costs associated with VS treatment.[10] [11] [12] Most of the most recent studies discuss the cost-effectiveness of SRS versus microsurgery; however, long-term costs have yet to be evaluated. Given the scant data available regarding costs associated with VS treatment, our group sought to perform a systematic review and meta-analysis of studies evaluating the costs associated with VS.

Methods

Search Criteria and Study Selection

A systematic review of the literature for cost of VS treatment was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.[13] The terms “vestibular schwannoma” and “acoustic neuroma” were used for search terms and qualified by the inclusion of terms that encompass variations in cost reporting. The search terms were queried using PubMed and Embase databases. An example of complete search syntax is provided in Supplement 2. Two independent reviewers (SK and GW) performed the data analysis and extraction, with disagreements settled by an additional author (CL). Studies that presented treatment cost information from 1990 to present day were considered. Letters to the editor, commentaries, and articles of editorials were excluded from review. The PRISMA search was conducted in stages of screening the title, abstract, and article. Treatment types that were considered included microsurgery, radiation, and conservative management. Papers that did not specifically report cost for individual treatment types were excluded in the full text screening. Our institution's Institutional Review Board was consulted and considered this study exempt from review.

Inflation and Cost Adjustment

Studies from all countries were considered. Historical currency exchange rates provided by OANDA were used to convert to a common denominational currency for this study, US dollars. If native exchange rates were provided in the article, the rate was used. Cost was corrected for inflation using the Producer Price Index for General Medical and Surgical Hospitals correcting to April 2022.

Data Extraction

Data were extracted into an Excel database. Qualitative measures were used to describe the treatment cohorts. Statistical analyses for quantitative analysis of treatment groups were performed using R, version 4.0.1 (R Foundation for Statistical Computing). Data are presented as the percentage, mean, and standard deviation of inflation-corrected cost.

Results

A total of 407 articles were initially included in the analysis. After review, eight articles were noted to provide data on cost of treatment. The PRISMA flowchart is shown in [Fig. 1] for article selection. The included studies ranged in time from 1997 to 2020. Four (57.1%) of the studies were from the United States, one (14.3%) from the United Kingdom, one (14.3%) from Canada, and one (14.3%) from the Netherlands. In total, 687 patients were included across the seven studies.

Fig. 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram for the included articles.

The summary of mean costs of treatment for vestibular schwannoma is shown in [Table 1]. The average cost of resection was $54,321.99 ($10,243–95,590, n = 8; [Table 2]), radiosurgery $27,837.92 ($6,281–51,676, n = 6; [Table 3]), and observation $6,304.88 ($2,149–11,886, n = 3; [Table 4]). [Fig. 2] represents the ranges of inflation-adjusted reported costs per study. Three studies assessed cost across all three treatment modalities, of which conservative management was the reportedly favored treatment in two of the studies[1] [14] and radiosurgery was the reportedly favored treatment in one study.[15] The average cost of resection in the United States was $64,812.65 (n = 5) and globally was $36,837.56 (n = 3). The average cost of radiation in the United States was $26,813.74 (n = 3) and globally was $28,862.11 (n = 3).

Table 1 Summary of mean costs of treatment for vestibular schwannoma (USD)

	Surgery	Radiosurgery	Observation
n	8	6	3
Mean	$54321.99	$27837.92	$6,304.88
Range	$10,243–95,590	$6,281–51,676	$2,149–11,886

Fig. 2 Representation of mean cost breakdown by treatment modality, study, and country.

Table 2 Characteristics of studies reporting cost in microsurgery

Study	Mean cost	Inflation adjusted USD cost	Year reported of cost	No. of patients	Tumor size mm (diameter)	Age	M / F	Favored treatment?
Banerjee et al 2008[10]	$23,788	$32,713.65	2008	53	>30 mm	Mean = 48.2	NA	Radiosurgery
Caruso et al 2015[25]	$67,538	$82,553	2015	11	NA	NA	NA	Radiosurgery
Gait et al 2014[14]	5277 pounds	$10,243.13	2013	283	< 20 mm	All ages	NA	Conservative management
van Roijen et al 1997[26]	20,072 Dutch guilders	$72,677.43	1997	145	<30 mm	Microsurgery: 52 Radio: 55	NA	Radiosurgery
Saliba et al 2020[27]	$68,417	$75,938	2020	30		18–65	NA	Middle Fossa approach
Verma et al 2009[1]	CAD$22402	$27,592.12	2009	72	<15 mm in CPA	Average: 60.8, range: 36–78	32 / 40	Conservative management or LINAC
Welling et al 1990[28]	Without complications: $9400 With complications: $39950	$34268.25	1989	70	mean: 16.5 mm (range: 3–55)	Mean: 49.7 (range: 23–90)	33 / 39 women	NA
Zygourakis et al 2014[15]	$80,074	$98,590	2014	33	NA	NA	NA	Radiosurgery

Abbreviations: CPA, cerebellopontine angle; LINAC, linear accelerator; NA, not available.

Table 3 Characteristics of studies reporting cost in radiosurgery

Study	Mean cost	Inflation adjusted USD cost	Year reported of cost	No. of patients	Tumor size mm (diameter)	Age	M/F	Favored treatment?
Banerjee et al 2008[10]	$16,143	$22,200.12	2008	53	>30 mm	Mean = 53.9	NA	Radiosurgery
Caruso et al 2015[25]	$37,840	$46,252.55	2015	11	Not given	NA	NA	Radiosurgery
Gait et al 2014[14]	3236 pounds	$6,281.36	2013	283	< 20 mm	NA	NA	Conservative management
van Roijen et al 1997[26]	14,272 Dutch guilders	$51,676.58	1997	145	<30 mm	Mean = 55	NA	Radiosurgery
Verma et al 2009[1]	CAD$27659	$28,628.38	2019: conversion: 0.92 US$ per CAD$	72	<15 mm in CPA	Mean = 60.8, range: 36–78	32 / 40	Conservative management or LINAC
Zygourakis et al 2014[15]	$9,737	$11,988.55	2014	42	NA	NA	NA	Radiosurgery

Abbreviations: CPA,—; LINAC, linear accelerator; NA, not available.

Table 4 Characteristics of studies reporting cost in conservative management

Study	Mean cost	Inflation adjusted USD cost	Year reported of cost	No. of patients	Tumor size, mm (diameter)	Observation length	Age	M / F	Favored treatment?
Gait et al 2014[14]	2513 pounds	$4,877.96	2013	283	< 20 mm	6 months min	NA	NA	Conservative management
Verma et al 2009[1]	CAD$9651	$11,886.95	2009	72	<15 mm in CPA	121 months median	Mean = 60.8, range = 36–78	32 / 40	Conservative management or LINAC
Zygourakis et al 2014[15]	$1,746	$2,149.74	2014	12	Not given	NA	NA	NA	Radiosurgery for > 45, surgery for < 45

Abbreviations: CPA,—; LINAC, linear accelerator; NA, not available.

The risk of bias of the cost studies (outlined in [Table 5] with criteria in [Table 6]) ranged from 1 to 4, with 7 (87.5%) were level 3 or above. Of the eight studies, five (62.5%) separated out cost elements into either direct or indirect costs during the hospital stay and/or follow-up.

Table 5 Risk of bias and cost characterization

Study	Risk of bias	Separates cost elements?	Indirect costs?	Direct costs?
Banerjee et al 2008[10]	4	N	N	N
Caruso et al 2015[25]	3	N	N	N
Gait et al 2014[14]	1	Y	N	Y
van Roijen et al 1997[26]	1	Y	Y	Y
Saliba et al 2020[27]	2	Y	Y	Y
Verma et al 2009[1]	2	Y	Y	Y
Welling et al 1990[28]	3	N	N	N
Zygourakis et al 2014[15]	2	Y	Y	Y

Table 6 Risk of bias levels

Level	Definition
1	Multi-institution costs, with detailed cost breakdown (direct, indirect, surgical); adjusted for inflation
2	Single-institution costs, with detailed cost breakdown (direct, indirect, surgical); adjusted for inflation
3	Multi-institution costs, without cost breakdown (direct, indirect, surgical); not adjusted for inflation
4	Single-institution costs, without cost breakdown (direct, indirect, surgical); not adjusted for inflation
5	Charges, or not well defined between charges/costs

Discussion

We performed a systematic review and meta-analysis in accordance with PRISMA guidelines analyzing studies that evaluated costs in VS. Only eight articles were found from 4 different countries describing costs associated with VS management. On average, we found that surgical resection was double the cost of radiosurgery and around eight to nine times the cost of observation. Of the cost studies we analyzed, seven (87.5%) were level 3 or above. Based on our risk of bias, [Table 1] study was a single-institution study reporting costs without a breakdown in the type of management. Studies that aim to understand the true cost of VS care must be comprehensive and include multi-institutional data with a cost breakdown between direct, indirect, and surgical costs. The current literature is lacking such detailed evidence.

The cost of resection was 1.7 times higher in the United States than it was in other countries. However, the cost of radiation therapy was similar between the United States and other countries. The differences in cost of healthcare spending for the resection in the United States are likely multifactorial. For example, the United States spends more than two times per capita on healthcare than other developed countries.[16] Additionally, there is government-based healthcare in other countries comparted to the private insurance-based system that add high overhead costs.[17] Multidisciplinary care that includes neurosurgery and otolaryngology could potentially play a role. These differences become more muted when we consider radiation therapy, which is typically performed by a multidisciplinary team in the outpatient setting.

While many other countries like the UK use a multidisciplinary care model to perform resection,[18] the cost of personnel in the United States is substantially greater when compared with that of other countries. The compensation of physicians in the United States is five times greater than an average US employee, which is greater than the relative compensation internationally ranging anywhere from one to four times the average employee in that respective country.[19] In fact, the high costs of VS surgical care everywhere could be partially attributed to the fact that there are often two surgical teams involved. In hospitals that do use a multidisciplinary team, it is possible that different teams have different ways of managing patients that may increase or change the services rendered for the patient (i.e., both teams following the patient postoperatively, different materials used).

A key driver of cost and opportunity for cost reduction is hospital length of stay.[20] As surgical management is associated with an increased length of stay comparted to nonsurgical management, total costs are intrinsically higher. The cost reduction opportunity, therefore, becomes strategies that reduce the length of stay, specifically any intervention that results in more efficient inpatient stays post-op. Additionally, optimization of postoperative outpatient costs can also have a big impact on overall cost. Comparing post-surgical VS care (such as length of stay) in the United States and globally could prove to be another variable in explaining the cost differences between the two.

For cost management in VS, the observation period is an important consideration. In this study, two of the articles provided insight into their observation period, which varied from a minimum of 6 months to a median of 121 months.[1] [14] In theory, patients managed with surgery initially will have higher upfront costs but may benefit in the future from lower follow-up costs due to less frequent visits and treatment relative to patients who are observed and later operated on. However, there is the possibility that patients observed conservatively will never undergo resection and therefore never incur the cost of surgery. Verma et al provided that conservative treatment carried a 35% failure rate with a comparison of tumor growth rates between the successful and failed observation groups at 0.2 mm/year and 3.2 mm/year, respectively.[1] With more careful follow-up and MRI screening, a study by Deen et al was able to show an 85% success rate in elderly patients managed conservatively over 3.4 years.[21] Evaluating growth in general, Hoistad et al reported 54 of 102 (53%) of conservatively managed patients showed no tumor growth at all.[22] While the optimal (i.e., most cost-effective) screening pattern for VS is not a set standard of care, Verma et al used MRI scanning performed every 6 months for the first year, and then annually for a period of time at the discretion of the neurosurgeon, and finally every 2 to 3 years as required.[1] Neurosurgeon discretion on scanning frequency could also vary with patient factors such as age of the patient. Zygourakis et al found that upfront treatment was always cost-effective, with initial surgery favorable for patients less than 45 years old and initial radiosurgery cost-effective in patients older than 45 years old.[15] Cost-effective treatment and the decision to observe is a nuanced choice with many different patient considerations. Further randomized studies should aim to clarify the optimal standard of care for patients.

In our analysis, we were able to analyze the costs from multiple centers and convert reported costs into inflation adjusted 2022 dollars. Among all the articles reviewed, there was a wide range of costs. Given the increased focus on healthcare costs and legislation requiring price transparency, understanding costs associated with VS treatment is vital for equitable and effective healthcare delivery.[23] Recent legislative efforts have focused on making prices more transparent. In July 2022, the Centers for Medicare and Medicaid Services (CMS) enacted the “Transparency in Coverage” rule that enables consumers to know the cost of covered services before receiving care. While cost should never be the primary determinant of VS management, public knowledge of procedural costs can potentially apply downward pressure on them.

Many of the reviewed articles report internal hospital costs and have a high degree of interhospital variability. While actual reimbursement and cost data would be most beneficial, such information is difficult to reproduce as it is typically considered proprietary information. Such information, at the present time, is not publicly available. Within the United States, a detailed quantitative analysis of consumer cost will be possible after the provisions of the CMS rule become fully complied with in 2023 and 2024. Once full compliance of the CMS rule is achieved, researchers will be able to use consumer cost data to calculate both nationwide and regional cost averages of both VS surgical resection and conservative management.

Clearly a need exists for patients to compare the costs of VS management as the elective nature of its management can allow patients to choose from different hospitals, while hospitals themselves can compare their own costs to national and global standards.[24]

Conclusion

Our findings describe the limited data on published costs for treatment of VS. The paucity of data and significant variability of costs between studies indicates that this end-point is relatively unexplored, and the significance of treatment cost is likely poorly understood. Given the relative equipoise between treatment modalities in some scenarios, better understanding of this end-point will help physicians make more responsible recommendations in the resource-constrained environment of modern healthcare and this analysis should serve as a starting point for more robust analysis into cost-effectiveness of treatment for VS.

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