Cancer is a malignant tumor that usually originates from epithelial tissue. Some cancer patients may not have abnormal manifestations in the early stage, but some patients in the early stage of cancer may also have symptoms such as lumps, abnormal fever, pain, cough, cough, diarrhea, abdominal pain, chronic ulcers, emaciation, weakness, enlarged lymph nodes, difficulty in swallowing and abnormal bleeding. Different primary tumors have different early clinical manifestations according to different primary sites. For example, early stage skin cancer patients usually present with erythematous papular lesions, usually with scaly flaking and scab formation. Early breast cancer patients usually present with lumps in the breast, abnormal breast skin, and nipple discharge. Patients with early stage leukemia usually show symptoms such as fever, bleeding, anemia, enlarged lymph nodes, bone and joint pain, and sternal pressure pain. Patients with early stage of cervical cancer usually show symptoms such as spotting and irregular vaginal bleeding after intercourse and defecation, increased leucorrhea, and pain in the lower abdomen. Meanwhile, there are also most cancers without obvious symptoms in early stage, such as lung cancer, colorectal cancer, stomach cancer, liver cancer and so on. Therefore, it is recommended that people who suspect they have cancer and other people in general should go to hospitals for regular medical checkups. If cancer exists, it should be treated early to help improve the cure rate, prolong the survival period and improve the quality of life so as not to miss the best time for treatment.