Thank you for bringing up the very important and relevant topic of Endocrine Incidentalomas.
Cascade Effect Is A Problem in Endocrinology.
Mold & Stein apparently coined the term cascade effect, in reference to medical technology, in a 1986 article in the New England Journal of Medicine. Cascade effect refers to a process that proceeds in stepwise fashion from an initiating event to a seemingly inevitable conclusion. The chain of events in which an initiating factor (an unnecessary test or procedure, an unexpected result, or patient or physician anxiety) occurs with increasing momentum followed by a series of events that result in ill-advised tests or treatments that may cause avoidable adverse effects, increased risks and/or morbidity. The further events progress, the more difficult they are to stop. Unfortunately, their use in routine care sometimes proves futile or even harmful. The adverse effects and consequences of new technology are often unanticipated.
Examples include discovery of endocrine incidentalomas on head and body scans; irrelevant abnormalities on spinal imaging; tampering with random fluctuations in clinical measures; and unwanted aggressive care at the end of life. Published medical literature states, "n patients with an incidental asymptomatic pituitary microadenoma, a single PRL test may be the most cost-effective management strategy" that determines further medical care.
Health professionals and laypersons alike tend to equate new medical technology with better-quality health care, assuming that newer is better. Much of the scientific literature on diffusion of innovations focuses on the anticipated beneficial effects of new technology and methods to ensure its rapid adoption. Technologic advancement in radiologic imaging has contributed to the development of an era during which preclinical or subclinical disease is detected in patients with incidentally discovered pituitary masses. However, many new medical technologies are introduced and disseminated with only modest evaluation of efficacy, optimal indications, or impact on practice.
Subjecting patients to unnecessary testing and treatment is associated with risk. In addition to its initial cost, testing may result in further expense and harm as false-positive results are pursued, producing the "cascade effect" described by Mold and Stein. The extensive evaluations performed for some patients with incidentally discovered masses may reflect the unwillingness of many physicians to accept uncertainty, even in the case of an extremely unlikely diagnosis.
This unwillingness may be driven, in part, by fear of potential malpractice liability, the failure to appreciate the influence of prevalence data on the interpretation of diagnostic testing, or other factors. The major justification for further evaluation of these patients is not so much to avoid morbidity and mortality for the rare patient who truly is at increased risk but to reassure patients in whom further testing is negative and the physician.
Physicians must take care not to create inappropriate anxiety in patients by overemphasizing the importance of an incidental finding unless it is associated with a realistic clinical risk. The initiating factor is often physician anxiety, which may result, for example, in a diagnostic test, an unexpected result, and a chain of subsequent events that are ultimately to the patient?s disadvantage. Physicians who are anxious about a patient?s problem may be tempted to do nearly anything in order to reduce their own anxiety.
The first step typically appears to be a benign action, such as ordering a diagnostic test; however, the discovery of an unexpected abnormality leads to progressively riskier and costlier interventions that seem simultaneously unnecessary and unavoidable. Similarly, as physicians try to explain each new ambiguous result, they become ensnared by their own actions.
Mold &Stein pointed out that in clinical care, cascade effects could be triggered inappropriately by incomplete data gathering; over interpretation of an abnormal lab result; underestimation of the risks of a test or treatment; underestimation of the possibility of false-positive results; and intolerance of ambiguity by the physician. Because of the near inevitability of certain cascades once they are initiated, the best chance of preventing unnecessary adverse consequences may be to prevent the triggering event.
Common Triggers For The Cascade Effect.
A wide variety of likely triggers have been identified, relating to both psychological and cognitive factors, as well as cultural attitudes and perverse incentives Common triggers include failing to understand the likelihood of false-positive results; errors in data interpretation; overestimating benefits or underestimating risks; and low tolerance of ambiguity. Excess capacity and perverse financial incentives may contribute to cascade effects as well.
Shotgun Testing.
A nearly ubiquitous feature of modern medical practice is the panel of laboratory tests ordered as a cluster.
Underestimating the Likelihood of False-Positive Results.
For many biochemical tests of blood or urine, the normal range is simply defined as two standard deviations from the mean of a healthy population. By definition, therefore, about 5% of results on each test from normal
Defensive Medicine.
Physicians sometimes request unnecessary tests or treatments in order to avoid medicolegal liability for a missed diagnosis or treatment opportunity. However, poorly thought-out testing may sometimes lead to more patient harm than good, paradoxically increasing medicolegal risks. Formal decision analysis produces the somewhat surprising result that defensive medicine necessarily reduces the overall quality of patient care. This finding contradicts arguments that defensive testing may further the interests of both doctor and patient. The reason is related to the problem of false-positive and false-negative tests. Decision analysis allows calculation of an optimal testing threshold: a pretest likelihood of disease that makes testing the preferred strategy over simply treating without a test or not treating at all. This threshold depends in part on the true- and false-positive rates of the test, and the consequences of those errors.
Inappropriate Screening.
If a physician widens the range of possibilities over which he or she prefers testing in order to reduce liability, then some patients who would be better left untreated will instead be tested and treated if the test is positive.
Errors in Data Interpretation.
Similarly, some patients who should be treated will instead be tested, and treatment withheld if the test is negative. The argument is theoretical, and actual practice may rarely conform to the optimal strategy in any event, for a number of reasons. Nonetheless, the analysis suggests that defensive medicine is not merely a problem of increased cost, but also one of reduced quality-of-care .
Consequences Of Cascade Phenomena.
Perhaps the most worrisome potential consequences of cascade phenomena are iatrogenic illness, morbidity, and mortality. Starfield has summarized some of the evidence for adverse effects that occur because of iatrogenic injuries not associated with recognizable error. These include some 12,000 deaths a year from unnecessary surgery, 80,000 deaths per year from infections in hospitals, and 106,000 deaths per year from non?error-related adverse effects of medications. It is impossible to determine what fraction of these are related to cascade effects, but we may speculate that it is a substantial fraction.
Data such as those from randomized trials of more aggressive or conservative management for acute coronary syndromes suggest that the aggressive strategy does not improve mortality, and its complications may increase mortality in some settings. Expert panels have judged that a substantial fraction of back surgery in the United States is unnecessary and exposes patients to unnecessary complications and even mortality.
The abundance of technology and specialists in the United States, compared with most other developed countries, has not assured better public health: The United States ranks tenth or below for indicators such as low birth weight percentage, neonatal mortality, years of potential life lost, and life expectancy at age 1, age 15, and age 40.
A less obvious consequence of cascade phenomena may be labeling effects for patients who have no disease. This problem has been demonstrated, for example, among children with benign heart murmurs, who experience greater restriction of physical activity than children without cardiac murmurs, despite having normal hearts. Anecdotal experience suggests that many patients who have spinal MRI tests attribute great importance to findings of bulging discs or other degenerative changes, despite evidence that these are as common in asymptomatic patients as among those with back pain.
There is some evidence to suggest that simply attaching a diagnosis to patients who were previously unaware of having high blood pressure may result in greater work absenteeism, regardless of whether therapy is begun. Thus, labeling effects may be associated with unnecessary disability.
Unnecessary costs are an obvious consequence of cascade effects. The follow-up testing required for unexpected abnormalities, ongoing monitoring, and management of complications for unnecessary procedures are all examples of cost without benefit in the health care system. One of the mechanisms by which treatment complications may occur is tampering with stable conditions. Tampering occurs when adjustments are made to correct deviations in a system that reflect random variation rather than systematic change. Intervening in response to random variations actually causes a system to become less stable and increases the likelihood of unnecessary treatment and adverse events. Modern physicians are flooded with measurements as we monitor a host of physiologic phenomena.
Preventing cascade effects may require better education of physicians and patients; research on the natural history of mild diagnostic abnormalities; achieving optimal capacity in health care systems; and awareness that more is not the same as better.
