Among autopsied cases every third case of cancer is only discovered by autopsy or correctly diagnosed with regard to his localization or structure. 2. 90% and more of all cancer of the breast, the skin, the upper alimentary and aerial tract, of the uterus and the vagina and vulva are clinical correctly diagnosed, but only 70% of malignant lymphomas and cancers of the lung, the stomach, the bowel and the ovary. More than 50% of all cancers of the prostata gland, the urinary tract and the pancreas are exactly clinical diagnosed, but the diagnosis of tumours of the brain, the biliary tract and the liver is worse. 3. In about 10% of all clinically diagnosed cancers any cancer does not exist and 10% have another cancer than expected. The clinical and the epidemiological aspect of such cancers is perturbed by these positive false diagnoses. 4. The group of negative false diagnoses descends only from deaths without suspicion for cancer. If cancer cases are more often autopsied than other deaths, the percentage of negatives erroneous diagnoses decreases in spite of the number of unknown unautopsied cancer cases increases. 5. Among the present autopsy rates about 10% (or more) of all cancer cases are not included in medical statistics.
