miércoles, 18 de mayo de 2011

Dopping and prostate. (Clembuterol and overdiagnosis)

Today I will join two of my hobbies to explain a concept that regards the two, cycling and science. The common point is the need to differentiate between two concepts: "false positives" and "overdiagnosis." It seems that we are talking about two similar technical terms, since they both are finding evidence of an abnormality, but they hide significant differences. As an example in the case of cycling can use the finding of a very, very small amount of clembuterol in the urine of Contador; in the case of the prostate we can use the presence of some subtle morphological changes in minimum samples obtained from apparently normal prostate glands of patients otherwise healthy, seen with a low magnification microscope. If it were the case of false positive doping findings, the rider actually did not submit any presence of clembuterol in urine, limiting the first findings just to a technical error in the lab that confused one substance to another. In subsequent analysis the substance would have disappeared, confirming the false positive and Contador would not have being accused of cheating. But the doping control system, as designated to prevent cheating, has suffered with severe prior cases and has tried to improve still further, prioritizing the elimination of false negative. It tends to use detection systems so perfect that they are able to discover traces of any substance in quasi molecular levels. It is intended by this that any athlete who has been in contact with any molecule of the prohibited list will be immediately accused of cheating. 

The same applies to prostate cancer risk when some healthy man, naively let the medical system look at him and gets 
positive PSA, with a great disappointment must undergo the necessary counter-analysis what in this case is a biopsy through the rectum and only if it is negative after several painful attempts will be labeled a false positive. But just as happens in the antidopping fight , the problem does not end here, frustration with the false positives, rather than celebrate the absence of the dreaded problem, tends to stimulate the search for new ways to keep discovering more cancers, by reducing quantities of PSA needed to make a positive or redefining the abnormal prostate cells suspected of being diseased. This leads to the second term I would like to explain here: overdiagnosis.
If the false positive implies its own falsity in the term himself, and it implies presumably will
have no  consequences, the athlete will left spotless and the patients will be returned to their normal lives, overdiagnosis does not leave things as they . Overdiagnosis is the diagnosis of a disease that will never lead to suffering, or evolve, or kill, but induce the label and forced to suffer the same treatment as if the disease crippling exist. Overdiagnosis in medicine arises when searching for cancer in early stages but no one really knows whether they are cancer or not, but fear tends to act as if they were. The false positive is able to uncover using a more specific test, but overdiagnosis uses tests that assigns full specificity, albeit tacit, pre-scientific, and induced to act on healthy patients as if they were risking their lives to a cancer threatening.
Overdiagnosis not only exists in medicine applied to cancer, also acts on other medicine and live  aspects, and one of them can be the fight against doping. Ultra sensitive tests can detect traces of substances, and such detection can be corroborated in other counter-analysis with the same precision, giving a sense of specificity equivalent to prostate biopsies. Everyone assigned to the prostate cancer patient who has found such a finding on biopsy, although do not feel sick, even though they do not touch if you see any tumor in the ultrasound, or scanners, even though most patients in their situation will never get sick of prostate and can get rather old, although the rate of such findings in the autopsies of healthy people is much higher than the actual presence of total real patients. The poor people suffering overdiagnosis suffer stress, operations, treatments and many tests despite being healthy. The unfortunate athlete who is found traces of any chemical substances that actually invade the air, water or food, will not be entitled to the false positive advantage
s and will suffer in their flesh wath in such a perfectionist society means the overdiagnosis capable of operating at cross healthy people and declare  cheater to top honored athletes.

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