Why does cancer recur?

There are many reasons for cancer recurrence, and there are also many hypotheses and opinions at present. Cancer recurrence should be caused by many reasons.

1. Surgery cannot completely remove cancer.

As a malignant tumor, cancer has the characteristics of infiltrating into surrounding tissues. And the normal tissues around you, you have me and I have you, it is difficult to distinguish. When we do surgery, we usually expand the scope to remove the tumor. For example, if the diameter of a tumor is 10cm, we will remove a range with a diameter of 13cm to ensure that the tumor can be completely removed. Because normal tissue can't be excised excessively, otherwise it will affect the function, so doctors try to excise it without affecting the normal function.

However, sometimes, some normal tissues contain very small amounts of cancer cells. Just like a mung bean mixed with a thousand red beans, it is hard for us to think that there is anything abnormal here. This mixed mung bean may become the seed of cancer recurrence in the future.

2. Secret transfer

We know that metastasis to distant organs is a feature of cancer. For example, lung cancer cells like to metastasize to the prostate and bones. Now we have petct, through which we can find out whether there are metastases in all organs. However, sometimes, only one cancer cell or only a few cancer cells are metastasized. At this time, the current technology may not be found at all. These undeveloped cancer cells that sneak into distant organs may also become the source of cancer recurrence in the future.

In Europe before, there was an old lady with liver cancer who donated her corneas, kidneys and other organs. At that time, no cancer cells were detected in these organs. Later, several people who received the transplant suffered from liver cancer. Through DNA testing, it was found that these liver cancer cells were all from the old lady.

The immune system has lost cancer cells, which are mutated from our normal cell genes. Our normal immune system can find and destroy these mutated cells. Our cells are mutating almost all the time, but it is up to our efficient immune system to deal with these problem cells in time.

However, the immune system of cancer patients is problematic and it is impossible to effectively monitor and eliminate these variants. Therefore, even if the cancer is surgically removed, the patient's immune system can't recover. Therefore, if cells mutate again in the future, they still cannot be effectively removed.

I know a friend's wife who had thyroid cancer, breast cancer and ovarian cancer. She had many operations before and after, and finally committed suicide because of depression. ...

The genetic defect of cancer patients makes them prone to cancer.

As we all know, cancer is related to genes, and some families like to get cancer. Surgery, chemotherapy and radiotherapy can only kill existing cancer cells, but can't change the patient's genes. Patients are born with genes that make their cells more susceptible to cancer. Therefore, after the operation, their normal cells may still become cancerous, leading to cancer recurrence.

5. Carcinogenic factors persist

For example, smoking, drinking, eating food containing aflatoxin, continuing to drink polluted water, continuing to breathe polluted air and so on. If the injury continues, the cancer will still recur.

For the above reasons, malignant tumor, that is, cancer, is easy to recur.