Why is cancer so hard to cure? It's always been something that everyone wants to know. I have summarized that the reasons why cancer is difficult to cure are probably the following aspects:
What is the heterogeneity of cancer cells? Heterogeneity of cancer cells refers to the fact that there are many cancer cells in the same tumor, but the properties of these cancer cells are not exactly the same, and they are often a mixture of different cancer cell populations that are pathologically differentiated. Taking gastric cancer as an example, in the pathological specimens of gastric cancer removed by surgery, medium- and low-differentiation adenocarcinoma cells can be found, and there are also mixed with imprint cell carcinoma and mucous adenocarcinoma cells. The occurrence of this condition is related to the occurrence of stomach cancer lesions. Because gastric cancer is the occurrence of gastric mucosal cells under the influence of long-term carcinogenic factors, and gastric cancer-causing factors affect almost all gastric mucosal cells, rather than cells confined to the site of gastric cancer. Because the anatomical site and functional localization of gastric mucosal cells are different, the influence of carcinogenic factors will be different. Of course, the anti-cancer ability of different gastric mucosal cells is also different. Since then, it has also led to the gastric cancer patients in the stomach, resulting in the production of diseased gastric mucosal cells at different stages of lesions and gastric cancer cells with different degrees of pathological differentiation, which is the reason for the heterogeneity of gastric cancer cells.
cancer cell
This condition will be further aggravated as the cancer progresses. The emergence of cancer cell heterogeneity will make the clinical use of anti-cancer drugs become only effective in killing some cancer cells, which also leads to the consequences of poor efficacy of cancer patients.
In addition, for cancer cells that have become cancerous, if they continue to be affected by carcinogenic factors during their proliferation process, they will still lead to further changes in oncogenes and tumor suppressor genes in cancer cells, resulting in further changes in the differentiation of pathological tissue cells of cancer cells, and this change often leads to the pathological differentiation of cancer cells more and more deviating from normal cells, becoming less and less malignant, and even undifferentiated cancer cells, which is the variability of cancer cells. For example, when an early tumor is diagnosed, it is often a highly differentiated adenocarcinoma, and as the tumor enlarges and metastasizes, it often becomes a low-differentiated adenocarcinoma or even a combination of other types of components. This variation of cancer cells will make it increasingly difficult for scientists to kill the changed cancer cells with drugs.
Also, when treating advanced cancers, chemotherapy drugs are only effective for sensitive cancer cells, and targeted drugs are only effective for cancer cells with targets. The treatment of the above anti-cancer drugs, while killing some cancer cells and alleviating the patient's condition, also brings drug side effects, causing damage to the human immune system, creating a living space for leaving cancer cells that cannot be killed, at the same time, these toxic drugs will further stimulate the human body to regenerate cancer cells that are difficult to kill, resulting in the condition of cancer patients deteriorating again and difficult to pick up, making treatment at a loss.
Metastasis of cancer cells
Easy to infiltrate and spread and distant metastasis, which are innate characteristics of cancer cells. Intermediate and advanced cancer patients are prone to metastasis is a situation that everyone is very familiar with, that is, early malignancy, if the degree of malignancy of pathological tissue cells is high, it is also easy to metastasis early, such as small cell lung cancer is such a typical example. Rapid proliferation and early extensive metastasis are its characteristics, clinical studies confirmed that 60% to 88% of lung cancers have brain, liver, bone or adrenal metastases at the time of initial diagnosis, and only about 1/3 of patients are confined to the chest.
Because when cancer metastasizes far away, it also means that its metastatic lesions also gain the ability to continue to metastasize, and since then, the metastasis pathways of cancer cells in cancer patients have become more and more complex, and more and more organs can be disseminated. It is clinically difficult to cut off the metastasis of cancer cells and remove cancer cells hidden in different organs of the human body, and the result will be that the cancer will not be controlled, resulting in the patient's disease progressing and worsening and dying.
Of course, nothing is absolute, such as bowel cancer after a single liver metastasis or lung metastasis, the cancer can be cured by removing the primary cancer and metastatic lesions. In addition, even if it is impossible to cure cancer, it also slows down the progression of cancer through treatments such as radiofrequency, radiotherapy, chemotherapy, and tumor reduction surgery, so that cancer patients can benefit.
The function of the human organs is done by many anatomy and functionally similar tissue cells closely combined together, when a small number of tissue cells are damaged and lose function, due to the compensatory role of tissue cells in other parts, basically will not have any impact on the function of human organs. When the cancer lesion is in the early stage, such as when the cancer is only about 1cm in size, it will hardly have any impact on the function of the human organs, and its invasion hazard ability and metastasis risk are also very limited. Therefore, early cancer basically has no obvious clinical manifestations, and it cannot be found without cancer screening physical examination.
If cancer in the body is not found, cancer cells will naturally continue to proliferate and grow according to their natural laws, and the result will be that the progression of cancer diseases will worsen, and slowly the human body will have more and more obvious clinical signs and symptoms of cancer. By the time cancer patients find that they are obviously unwell and seek medical treatment, most of the cancer diseases they suffer from are already intermediate and advanced cancers. It is well known that the prognosis of patients with middle and advanced cancer is notorious. The reasons for all this, in addition to the cancer itself, are related to the lack of health awareness of the Chinese people, related to the long-standing bad habit of seeking medical treatment for diseases, and are also related to the reluctance to spend money on physical examinations and health care.
In short, the reason why cancer is difficult to cure is that the heterogeneity of cancer cells in the progression of cancer lesions is related to variability, making the treatment of cancer confusing. Second, the characteristics of tumors that are easy to spread and metastasize make people invincible. Third, early cancer lacks symptoms, it is difficult to find without physical examination, and when obvious symptoms are found, it is often a middle and advanced cancer, which is naturally difficult to cure.