For many types of cancer, the extent of disease at diagnosis (i.e., the stage of the disease) predicts the ultimate prognosis. However, this analysis of patients newly diagnosed with prostate cancer found that clinicians erred in determining the clinical stage in more than one-third of cases. Overreliance on physical examination results, underemphasis of imaging results, and inappropriate application of biopsy results all appeared to contribute to misdiagnosis. Diagnostic errors have also been documented in the pathologic diagnosis of cancer.