Predicting outcome: a fourfold delusion!

Diagnosis: a judgment about what a particular illness or problem is, made after making an examination. [Cambridge Dictionaries Online. Diagnosis. Cambridge University Press 2011. Accessed February 17, 2012. http:// dictionary.cambridge.org.] Diagnose (to): to recognize and name the exact character of a disease or a problem, by making an examination. [Cambridge Dictionaries Online. Diagnose. Cambridge University Press 2011. Accessed February 17, 2012. http://dictionary.cambridge.org.] Prognosis: (1) a doctor’s judgment of the likely or expected development of a disease or of the chances of getting better; (2) a statement of what is judged likely to happen in the future, especially in connection with a particular situation. Prognose (to): to make a prognosis. [Cambridge Dictionaries Online. Prognosis. Cambridge University Press 2011. Accessed February 17, 2012. http://dictionary.cambridge. org.] According to the definitions above, a diagnosis is an affirmation based on an examination, recognition and naming of the exact character of a present disease. For example the identification of Mycobacterium tuberculosis in sputum implies a certainty: the patient has tuberculosis. All to the contrary, prognosis is a statistical computation of what might occur in the future. By its very nature, statistical evaluation is uncertain. Statistics is nothing but a precise quantification of uncertainty. Diagnosis is certain; prognosis is uncertain. A patient with tuberculosis may die from his disease or he may not. Nobody will try to “adjust therapy to prognosis” for a tuberculous patient; antituberculous drugs will be prescribed. During the last few decades, and for reasons not entirely clear (some even suspect such as the redefinition of diseases according to the medications available in the market), in cases of cancer pathologists have been asked more frequently to evaluate the prognosis of (to “grade”) neoplasms on the basis of the histological characteristics of tumors. The “grading systems” are more and more elaborate, proliferate everywhere, occupying an ever-growing part of textbooks. This even goes to the point where diseases tend to be defined by their prognosis. It is not rare to find in the literature statements such as: “The evolution of dermatopathology, along with the development and introduction of new molecular biology techniques with the identification of new biomarkers, has opened a new field that may [emphasis ours] allow the classification of lesions in function of their prognoses in a completely objective and reproducible manner, putting an end to the eternal debates regarding the subjectivity of the currently utilized grading criteria.” [Arumi-Uria M. Dysplastic nevus: the eye of the hurricane. J Cutan Pathol. 2008;35 Suppl 2:16-9.] and even: “A diagnosis is a clinical tool that assists in the process of codifying patients into disease groups that share a common outcome and a common set of Predicting outcome: a fourfold delusion!