The diagnosis of tumor is a major issue related to the correct treatment. Without accurate and timely diagnosis, there is no way to talk about treatment. The correct diagnosis comes from the diagnostic basis, which can be divided into five levels: a. Clinical diagnosis A presumptive diagnosis based on clinical symptoms and signs, with reference to disease development rules, and after excluding non-tumor diseases. Generally, it cannot be used as the basis for treatment. Surgical diagnosis The diagnosis is made by surgery or various endoscopic examinations, only by the swelling seen by the naked eye, without pathological confirmation. Physico-chemical diagnosis is clinically consistent with cancer manifestations and supported by positive physico-chemical examination, such as X-ray, ultrasound, CT and MRI, or carcinoembryonic antigen and methemoglobin measurement. Diagnosis of cytopathology is made based on various exfoliated cells and aspiration cells. V. Histopathological diagnosis Diagnosis of various cancers made by pathological section after coarse needle aspiration, clamping, excision and removal. Among these five levels, the reliability of their diagnosis increases in order, with the fifth level being the most ideal and the goal we should pursue.