We all know: once cancer recurs, it often has the tendency to spread, and by then, treatment becomes more difficult and less effective. Today’s content briefly introduces why malignant tumors are prone to recurrence. Cancer recurrence refers to the reappearance of controlled cancer in the primary organ, or the cancer invades the lymphatic vessels or body cavity from the primary site, migrates to other places and continues to grow, forming the same type of tumor as the primary tumor. Some cancers may recur months or years after the initial treatment. There are several reasons for the recurrence of cancer: Cancer physique has not changed: Cancer patients have cancer because their body environment has “cancerous physique”, surgery, radiotherapy and chemotherapy have killed the cancer cells, but the regulation mechanism of cell differentiation in the patient’s body has not changed, and the environment for cancer cells to survive has not changed, so new cancer cells will be produced. Therefore, new cancer cells will be produced continuously, and the cancer will recur and metastasize. Incomplete treatment: Surgery can remove cancer cells that have formed a lump, and common radiotherapy and chemotherapy can kill all or part of adult cancer cells, but they are not good for juvenile cancer cells. When the patient’s immune function is low, once juvenile cancer cells wake up from dormant state, they will rapidly fission and mutate to form new adult cancer cells, which is the root cause of cancer metastasis and recurrence. Cancer cells have existed in the body of cancer patients for a long time, and surgery, radiotherapy and chemotherapy have eliminated most of the cancer cells in the body, but there are still about 1 million G0 stage (inactive and quiescent) cancer cells in the body of patients, which cannot be solved by surgery, radiotherapy and chemotherapy at present. What’s worse is that some cancer cells have already accumulated in the patient’s body and taken root to form microscopic lesions that cannot be seen by the naked eye or imaging, waiting for an opportunity to grow. These residual cancer cells and microscopic lesions are the culprits of future recurrence. Low immunity: The cells in normal human body keep on metabolizing day and night, and among the new cells formed every day, about millions of cells will undergo genetic mutation, and if a few mutated cells are not restrained by the immune system, they will further malign and form tumor cells. Under normal circumstances, the immune system of the body is always monitoring and destroying these mutated and malignant cells or cancer cells in time, once abnormalities are found, a large number of immune cells will be mobilized to destroy the “foreign molecules”, making it difficult to form a climate. If a person’s immune surveillance function is normal, he or she will be able to snipe carcinogens and cancer cells outside the body and destroy them in the bud. Chemotherapy is a treatment for cancer. Chemotherapy drugs not only kill tumor cells but also normal cells, which reduces the immune function of the patient’s body. To stop cancer recurrence, it is necessary to improve immunity after treatment, rebuild the body’s immune guardian function and repair the body’s regulatory function. Unhealthy lifestyle: After a series of treatment, cancer patients return to life and work and start a new life. Some of them start to smoke, drink and stay up late again, which are not healthy lifestyles. All of these may become factors for cancer recurrence.