13.1 Introduction

In general, it is safe to say that patients newly diagnosed with a brain tumor face a period of anxiety and uncertainty. Obviously, there are different implications among various types of tumors. Many malignant tumors carry very grim prognoses, while for other types of tumors, including vestibular schwannomas (VS), prognoses are much more favorable. This generally good prognosis, however, does not imply that the decision-making process for VS patients is less complicated. Indeed, given the various endpoints of treatment, many of which have major implications regarding quality of life and well-being, there is a very high level of complexity.

It is rare for the skull base surgeon or other subspecialist to make the initial diagnosis of VS. Patients usually arrive already having received opinions from initial diagnosing physicians, family, and friends, as well as from the expanding resources available from the internet, social media, and patient advocacy groups. The information obtained in the course of diagnosis may be useful, confusing, misleading, or some combination of all three.

Despite the fact that VSs are all benign schwannomas originating from the vestibulocochlear nerve in the internal auditory canal and cerebellopontine angle, each tumor displays unique characteristics and each patient presents with a particular clinical picture. There are a number of very distinct but generally successful management options available. Treatment must therefore be individualized, taking into consideration the particulars of both tumors and patients.

13.2 Measuring Outcomes in Vestibular Schwannoma Treatment

In some types of disease, outcomes can be measured and described simply. Examples include measured decrease in blood pressure following administration of an antihypertensive medication and 5-year mortality following treatment of cancer. For VSs, measuring results is considerably more complicated.

The traditional outcomes of VS treatment are complication rate, facial nerve function, and hearing status. Although there may be interobserver variability, these are all factors that can be objectively measured and quantified.s. Literatur Certainly, however, there are different tolerances for poor outcomes among different groups of VS patients. For instance, higher complication rates and worse facial nerve function are more acceptable in patients with giant VSs than in patients with intracanalicular tumors.

More recently, the importance of other, less readily quantified, outcome measures has come to light. Quality-of-life studies have shown that the importance of dizziness and headaches may meet or even exceed that of facial nerve and hearing function.s. Literatur Yet more indistinct are the questions of patient satisfaction and socioeconomic effects.s. Literatur ^,​ s. Literatur These are measures that may be influenced by any number of controllable or noncontrollable factors. It is critical to understand that despite the increasing nebulousness of various measures, each of these retains some validity in determining how patients end up doing.

13.3 Vestibular Schwannoma Data and Treatment Options

In the most basic terms, VS patients face the options of observation, microsurgical resection, and stereotactic radiation. Of course, in some situations, the correct course of action is wholly apparent, such as in the patient with a giant tumor who requires microsurgical resection or the elderly, infirm patient with a small but growing tumor who would best be treated with stereotactic radiation. A majority of patients, however, lie somewhere between the extremes, and in these patients several options remain reasonable.

In the middle is the situation of clinical equipoise, in which more than one treatment option can be considered equally valid. Thus, a Venn diagram can be created outlining the options available to patients in various clinical situations (Fig. 13‑1 ). It is important to understand, however, that borders between different areas are not distinct lines. Rather, a continuum of states exists, ranging from situations in which there is only one good option to situations of true equipoise. An intermediate state in which one option can be generally recommended over another but in which either option is ultimately reasonable exists.

As is evident to anyone in the field of VS treatment, there are clear differences of opinion from one practitioner to another in terms of the merits of the various treatment options. This is an unavoidable situation made possible by limitations in the measurability of the data regarding VS treatment. Most basically, there is no simple, binary treatment outcome measure. Various factors, including complication avoidance, facial nerve function, hearing, balance, ease of treatment, and other less well-defined aspects of quality of life are important, and the relative value of any one versus another is purely subjective.

Even for outcomes that can be measured, it is important to understand limitations of the data regarding VS treatment. Even most quantifiable outcome measures, such as facial nerve function, are subject to interobserver variability. As factors become more subjective, additional questions regarding reliability and validity become progressively more problematic. Furthermore, the quality of the data is in many regards not unassailable. Long-term follow-up of patients is only done with difficulty, and most series suffer from significant proportions of patients being lost to follow-up.s. Literatur The endpoints of studies are also often less than ideal when considering a diagnosis of VS. The utility of short-term studies is limited when considering treatment of a benign process with the goal of long-term survival, often many decades, with the best possible function and quality of life. It is essentially inherently impossible to answer some of the most important questions.

13.4 The Psychology of Decision Making

Given the multiplicity of treatment options and the need to make a decision based on numerous factors, the possible outcomes of which can generally only be described imprecisely, it is important to understand the ways in which people actually make decisions. Being primarily a social science question, academic analysis of this process lies outside the field of VSs or skull base surgery.

In his book, “Thinking Fast and Slow,” Kahneman has summarized the research in this area and proposed the “two-system” theory of decision making.s. Literatur As described by this theory, people use two competing cognitive systems to make decisions. System I allows people to unconsciously and automatically make decisions based on impressions and associations. An example is 2 + 2 = 4. System II allows people to consciously and effortfully analyze information in a focused and rational manner. System II is used to compute the answer to more complex mathematical problems.

In the course of daily life, the human mind utilizes both systems organically in order to reach conclusions and make decisions as appropriately as possible. It is easy to understand how system II takes over from system I when people face complicated questions that cannot be easily answered. As may be counterintuitive, however, when problems become even more increasingly complex, system II cannot adequately analyze information, especially if much of that information is conflicting. When system II is overwhelmed, people make decisions using the impressions generated by system I, and they use system II to justify these impressions. The best and most obvious example of this is politics. Few of us would argue that, most basically, people’s political views are derived from anything other than automatic, instinctual impressions.

Thus, in the treatment of VSs, it is important to understand that patients make decisions using a combination of both rational, thoughtful analysis and automatic, instinctual, subconscious thought. In the end, and probably in those cases in which the decision is closest to clinical equipoise and most complicated, it is usually system I which is ultimately dominant.

It is therefore important to understand that system I does not understand statistics or complex data. System I deals in impressions and is prone to various biases. For instance, a strong argument delivered confidently and forcefully will carry disproportionate weight, even if the data do not support any sort of strong position. Patients are also likely to assign disproportionate weight to the first opinion that they hear, even if this is from someone with little actual understanding or experience with VS care. System I also utilizes heuristics, or the substitution of a complex problem with an easier one. So, a patient may decide that microsurgical treatment is bad because a close relative deteriorated after craniotomy for a malignant brain tumor or that radiosurgery is bad because “radiation causes cancer.” To system I, a single anecdote may carry greater weight than all published data combined.

Of course, it is tempting to argue that all effort should be made to bolster system II against system I for these types of difficult decisions. The problem with this, however, is that social science research has shown that people who rely on system I or gut instinct to make important decisions with multiple reasonable options generally end up happier than those who attempt to overanalyze with system II.s. Literatur ^,​ s. Literatur

In order to maximize outcomes and patient satisfaction, those treating patients with VS should therefore understand two important points. First, is it easy to mislead patients by manipulating their underlying biases; second, in situations at or near equipoise, patients are likely to end up more satisfied if they are allowed to follow their own instincts in deciding the best course of treatment.

Related posts:

12 Multidisciplinary Care of the Vestibular Schwannoma Patient: Building a Skull Base Team 17 Linear Accelerator Radiosurgery for Treatment of Vestibular Schwannoma (Non-CyberKnife) 32 Management of the Facial Nerve During Vestibular Schwannoma Microsurgery 50 Reporting of Hearing Outcome Data for Vestibular Schwannoma 69 Vestibular Rehabilitation and “PreHab” in Sporadic Vestibular Schwannoma 83 Medical Therapy for Neurofibromatosis Type 2 Focusing on Vestibular Schwannoma

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