I have recently become interested in the topic of overdiagnosis with special reference to the practice of surgical pathology (see: Confusion Caused by Conflating "False Positive" and "Overdiagnosis" in Breast Cancer, Continuing Discussion of the Various Types of Diagnostics-Driven Cancer Overdiagnosis). I will take the term overdiagnosis to mean "overcalling" a diagnosis. Stated another way, the pathologist unconsciously drifts toward a more serious diagnosis on the basis of her or her training or perhaps unconsciously to avoid the error of undertreatment. Overdiagnosis sometimes leads to overtreatment but I suspect that undertreatment is more likely the cause of medical malpractice suits than overtreatment. I recently encountered an article discussing the extent to which patient safety is taught to medical students (see: Patient Safety: Conversation to Curriculum). The passage quoted below caught my eye:
Through such sessions, students can learn how medical errors are defined and how to tell an error from a negative outcome, said Dr. Melissa A. Fischer, an assistant professor of medicine at the University of Massachusetts Medical School. As she emphasizes to her students, “bad things can happen even when everything is done right.”
Hmmm. This article indicates that medical errors are different than negative outcomes and can be distinguished from them. I don't know the medical literature in the area of patient safety so I will need to "wing it" in this discussion. I will take negative outcome to mean that the patient's condition gets worse during treatment because of the natural history of the disease or because of unavoidable sequelae of the treatment itself. You may have all heard the old adage: the operation was a success but the patient died. I will take a medical error to mean that a discernibly wrong step or action was taken during treatment and the patient suffered from it.
I believe that most physicians, and most patients, are predisposed to treating a disease (i.e., take some overt action) rather than following the course of the disease, thereby postponing treatment until the condition worsens. The latter process is sometimes called watchful waiting. This is a common approach when early prostate cancer is diagnosed in older men. Nearly all therapeutic interventions (e.g, surgery, drug treatment) can lead to some negative outcomes. For example, most drugs have both known and unknown side effects. Some people never wake up from general anesthesia.
What are the negative outcomes of the clinical monitoring of a known disease, which is to say watchful waiting? One of them is that the patient is psychologically uncomfortable living in an untreated state. Another is that the disease progresses so rapidly that it quickly reaches an untreatable stage and the patient would have been better off having been treated earlier. This latter case is probably rare, given the fact that watchful waiting is reserved for the more indolent diseases and also because of the predisposition of most physicians is to actively treat most of their patients. However, I need to add that watchful waiting may soon become a more attractive clinical scenario as the sophistication of serum biomarkers and medical imaging improves. In other words, as the efficiency and efficacy of diagnostics improves, the penalty for observing an untreated disease diminishes.