There is no such thing as “which 4 types of cancers are difficult to eradicate”, but generally advanced cancers and cancers with higher malignancy have a lower cure rate. Cancer is a complex disease caused by heredity, gene mutation, environment and other factors. Generally, with the development of tumor, distant metastasis will occur when it progresses to the advanced stage. At this time, the patient’s condition is more complicated, the physical condition is poorer, and non-surgical therapies such as radiotherapy are mostly used for treatment, with a five-year survival rate of about 10% and a high recurrence rate. In addition, some malignant tumors with higher degree of malignancy and lower degree of differentiation have poorer prognosis, such as small-cell lung cancer, triple-negative breast cancer and pancreatic cancer. However, by paying attention to regular medical checkups and striving for early detection, early diagnosis and early treatment, a certain five-year survival rate can often be achieved.