New City Osaki Clinic homepage > Leading-edge cancer therapy > Cancer immunotherapy
When cancer is diagnosed, a standard treatment plan consisting of what is commonly called 3 major therapies, “surgical treatment (surgeries)”, “radiation therapy” and “anticancer agents”, is developed. When detected early, cancer is treated locally by surgeries or radiation therapy. In contrast, advanced or metastatic cancer cannot be treated locally, and therefore the patients’ condition is observed, while the entire body is treated by combining therapies, such as the administration of anticancer agents.
Anticancer agents basically target the cells that proliferate rapidly and inhibit their growth. They spread throughout the body when they are administered by drip infusion or taken by mouth. Therefore, they damage other normal cells with a high proliferation rate, which results in the risk of serious side effects. This risk imposes a heavy psychological and physical burden on patients and their family members.
Moreover, there would be no problem if such treatment with external agents or surgeries could subdue cancer 100%, but, unfortunately, cancer is likely to remain in the body and resume growing.
Under such circumstances, a treatment method was developed that activates humans’ natural immune system, which controls cancer. This new method, “cancer immunotherapy”, is currently attracting the most attention among different therapeutic options. The relationship between immunity and cancer has long been studied. Since 2000, this relationship has been scientifically proven and cancer immunoediting theory was proposed in 2004 in the United States, which quickly raised expectations for cancer treatment.
In the process of enhancing the immunity of patients themselves, there is no concern about side effects, which was one of the major sources of suffering for patients and their family members. The cancer immunotherapy can be used in combination with external treatment, such as the administration of anticancer agents and radiation therapy. While external treatment weakens cancer cells, immunotherapy activates inner strength using cutting-edge technology. In recent years, many reports on the results of immunotherapy have been published one after another, showing that it complemented the effects of the three major conventional therapies, while maintaining QOL (quality of life), regardless of the type of cancer. Thus, introduction of immunotherapy gives people involved in cancer treatment great hope.
Immune cells patrol the body and eliminate the sprouts of cancer cells immediately after finding them, anytime and anywhere. They do not stay in one site but monitor and inhibit the development of cancer throughout the body. For this reason, in addition to being effective in the treatment of cancer, immunotherapy is also attracting attention as a very effective preventive method for recurrence or the initial development in people with genetic concerns for the risk of cancer.
In cancer immunotherapy, the process of immune reaction to cancer is effectively used for treatment. Immunotherapy is roughly divided into cancer vaccine therapy, dendritic cell therapy, and activated lymphocyte therapy. Furthermore, activated lymphocyte therapy includes T lymphocyte (T cell) therapy, NK (natural killer) cell therapy, NKT cell therapy, and γδT cell therapy.
In cancer vaccine therapy, cancer antigens that are collected directly from cancer cells or artificially synthesized are administered as a vaccine. This therapy is based on the premise that a long process—in which cancer antigens are taken in the body, reach the lymph nodes, and give information to dendritic cells, and then, T cells receive the information, proliferate, are activated, go out of lymph nodes and reach cancer lesion—occurs in an orderly manner. Although this mechanism might work for healthy people with strong immunity, its actual efficacy in cancer patients is influenced by somewhat unstable factors such as whether or not cancer antigens can be taken in dendritic cells, or whether or not T cells can be activated, because the immunity is generally impaired in these patients.
Dendritic cell therapy is similar to cancer vaccine therapy, but one step is omitted. First, monocytes are collected from the blood and turned into dendritic cells. These dendritic cells are then given antigens, allowed to learn cancer information, and returned to the body. The administered dendritic cells go to the lymph nodes and give T cells the cancer information and activate them. Because the dendritic cells do not directly kill the cancer cells, it is essential to present the cancer information to the T cells that can reliably attack cancer cells, and to let these T cells proliferate. In addition, it should be verified how much of the cells injected in the skin can reach lymph nodes. As is the case with cancer vaccine therapy, dendritic cell therapy depends on the functions of the impaired immune systems of patients and therefore, the efficacy is unstable. In recent years, dendritic cells have been directly injected into cancer lesions instead of letting them reach lymph nodes.
Activated lymphocyte therapy aims at treating cancer by isolating lymphocytes from the blood, increasing them to a large amount, and returning them to the body. Unlike cancer vaccine therapy or dendritic cell therapy, it does not require the process of handing over cancer antigen in the body. Instead, cells that directly attack cancer cells are increased and activated. There are different types of activated lymphocyte therapy, T lymphocyte (T cell) therapy, NK cell therapy, NKT cell therapy and γδ (gamma delta) T cell therapy. The target and method are different depending on the cells activated. Issues associated with this therapy include whether or not activated lymphocytes returned to the blood vessels gather in the cancer lesions, and whether or not these lymphocytes have the capability to attack and kill cancer cells and the specificity in attacking other cells (property to attack only specific abnormal cells).
In immunotherapy, the patients’ own immunity is enhanced by taking the patients’ own immune cells out of their bodies and returning them to their bodies after proliferating and activating. The major characteristic of immunotherapy is that there is no concern about strong side effects, which was one of the major sources of suffering for patients and their family members.
At our clinic, 10 to 20 billion activated lymphocytes are administered at once. It was confirmed that these cells do not cause severe side effects other than fever even if they are administered in such a large amount. On the day of the administration, one in 5 patients have a fever around 38ºC, but this fever is quickly resolved, and it does not last until the next day. On the contrary, some patients feel that their physical condition was improved or that their skin looked shinier because their immunity was strengthened.
One of the major advantages of immune cell therapy is that it causes almost no side effects. We have to say, however, that this therapy is still insufficient when it is used solely for the treatment of advanced cancer. Although it can lower the tumor markers or delay the progression of disease by itself, it is necessary to improve the therapy or devise new ways to implement it in order to expect further efficacy, for example, in reducing the size of tumors or eliminating them. This is because, in short, cancer grows while inhibiting the immune response that removes cancer from the body, even when activated lymphocytes grown outside of the body are administered, the efficacy is considered to be limited because cancer cells already developed resistance to the immune function.
To solve this problem, immunotherapy can be used after weakening cancer cells and lowering the resistance to immunity by anticancer agents or radiation. Marked efficacy of such combination has been demonstrated. At the New City Osaki Clinic, immunotherapy is used without anticancer agents mainly for the purpose of prevention of recurrence or improvement of QOL. To treat advanced cancer, we recommend combined use with anticancer agents or radiation.