Evidence-Based Medicine, Conscience-Based Medicine, and the Management of Low-Risk Prostate Cancer

摘要

What began as a small crack in the solid concept of early detection and early treatment for prostate cancer has now widened and spread. Despite imperfections which limit their interpretation, the recently published randomized screening trials show there is only a small—or even no—improvement in survival from early detection over the first 10 years. One trial also showed that the number of patients (around 50) that must be treated to save one life is alarmingly high. These data come at a time when medical spending, long recognized to be beyond the nation’s means, is to be tightened and restructured along evidencebased guidelines with care being directed preferentially toward areas of proven benefit. The Institute of Medicine has drawn up national priorities for comparative effectiveness research, and the management of localized prostate cancer sits squarely in the first quartile. Indeed, it is the top-ranking oncologic priority. A perfect storm of clinical evidence and economic reality has arisen in which urologists and radiation oncologists need to examine the evidence, examine their souls, and start to carefully look at every new patient asking, before anything else—is treatment really needed at all? If it is not, and that will frequently be the answer, then they must be prepared to lead the patient along the less financially rewarding and decidedly unglamorous path of active surveillance. The training of resident doctors has to date been so focused on cure, and the culture of early detection/early treatment so deeply in-grained, that it is little wonder that this shift in thinking is yet to reflect itself in everyday practice. What is respectfully acknowledged at major meetings and in editorials is not, in the daily reality of the clinic, being applied to patients. Indeed, in the United States, the proportion of men being managed conservatively has actually been declining. The explanations, as hinted, are complex and rooted in a conflict between knowledge and belief with disturbing undertones of economic self-interest. It is time to practice consciencebased medicine. The PCPT (Prostate Cancer Prevention Trial) trial reported in 2004 demonstrated that systematic needle biopsy could find prostate cancer in 27% of all men with a normal prostate-specific antigen (PSA). Klotz has estimated that at current rates, one in five men will be diagnosed with prostate cancer during their lifetime. We know from the days when no attempt at curative treatment was the norm that no more than 3% of men ever died from this disease, and more recent experience tells us that a significant proportion of men are incurable even when their disease is detected early. Large mismatches between incidence and fatality occur elsewhere in medicine and have been reconciled in different ways. How this has been reconciled in prostate cancer forms the kernel of this debate. Until recently, United States physicians and advocacy groups have strongly favored immediate, curative treatment for all or most men with early prostate cancer. They have argued that this is little different from the treatment of high blood pressure or high serum cholesterol, strategies almost universally applauded. To address prostate cancer differently, it has been said, would be to apply double standards. The absolute risk reduction of stroke or a coronary event is low for any individual but treatment for the entire diagnosed population is justified because the treatments are effective, well tolerated, and relatively inexpensive. How does therapy for prostate cancer compare? Firstly, is it effective? The Scandinavian trials of both surgery and radiation therapy prove that some men with clinically significant, life-threatening, localized disease live longer as a result of their treatment. At 10 years, 19 men in one trial and 10 in the other needed treatment for a single life saved in a relatively advanced, nonscreen detected group of patients. It is far from clear, however, that low-risk, PS