Evidence About Effective Treatment
A number of studies have attempted to compare prostate cancer treatments, but they all have serious limitations -- most importantly that the men receiving the various treatments are usually different. For example, men who receive surgery are usually younger and healthier, while those who are followed without treatment (watchful waiting) are usually older. Men who are treated with radiation are typically somewhere in between. In general, for men with well-to-moderately differentiated disease, treatment appears to offer little benefit over no treatment. But for a subset of younger men with more aggressive-appearing early disease, surgery may yet show a survival advantage.
To compare treatments, researchers must have a large group of men randomly assigned to alternative treatments, so the treatment groups are similar. This way the differences in outcomes can be attributed more to the treatments than to the men receiving them. Such a study is in progress (The Prostate Cancer Intervention vs Observation Trial).
The Prostate Cancer Intervention vs Observation Trial: a randomized trial comparing radical prostatectomy vs expectant management for the treatment of clinically localized prostate cancer.
In lieu of conclusive evidence to compare treatments, one method researchers have used to compare treatment options is decision analyses. This combines the available evidence of benefit (survival, less-advanced disease) and balances it against the evidence of harm and then often uses some weighting to include personal values. These types of analyses reflect the complexity of prostate cancer screening and treatment decisions. They are somewhat controversial, partly because of the weaknesses of the evidence and partly due to the subjective nature of the weighing of values or utilities, as they are called.
The best-known decision analysis shows that the greatest treatment advantage occurs in the youngest men with the most poorly differentiated (most aggressive appearing) disease. When adjusted for quality of life, the survival benefit was at best about one year, usually less. And in men over the age of 70 there was no advantage, even a net harm from treatment.
A decision analysis of alternative treatment strategies for clinically localized prostate cancer.
Other decision analysis studies have produced even more pessimistic results of treatment, even a net loss of life expectancy per person screened.
