[Cancer screening and early diagnosis. Why? How? Where? Which ones? At what cost?].

Cancer is fighting with cardiovascular diseases for the first place as the number one killer of humans living in industrialized countries. Several factors contribute to the high incidence of cancers. The spectacular increase in life expectancy of individuals living in these areas is certainly one of the major causes that explain the steady rise of the number of patients suffering and dying from cancer. For most cancers, when the issue is fatal, it is usually after a long morbidity period often very difficult for the patient and with heavy public health consequences. Thus, a major challenge that the health professionals are facing is the reduction of malignant disease incidence. Primary prevention would be certainly the most successful strategy. However, its implementation is of extreme difficulty. Secondary prevention, non-exclusive to the primary one, represents probably the best approach to decrease morbidity and mortality linked to these diseases. Screening and early diagnosis are the two axes of such a strategy. The first one concerns the detection of a malignant lesion in an asymptomatic patient. Early diagnosis implies to consider with attention and explore any signs or symptoms that can be easily missed by the patient or the doctor and, hence, could be the first indication of a progressing cancer. The impact of cancer screening on the mortality rate due to cancer is still the subject of intense debates, while the efficacy of early diagnosis is unanimously recognized. Still, it is cancer screening that is the center of most attentions....