RADIATION THERAPY AND ITS EFFECT ON THE IMMUNE RESPONSE
Just like chemotherapy and ablation, radiation kills tumors. Then, residues of the dead tumor tissue can act as antigens sent to the immune system. In general, radiation therapy can be considered immunosuppressive, but when it is combined with the immunotherapy process it creates a synergy.
Overall, Cryoablation is considered to be more effective than radiation in its ability to stimulate an immune response. However, it will be easier for most patients to choose a radiation procedure than cryoablation.
It is much easier to get health insurance coverage for a radiation procedure. Therefore, most patients go to this process, where it is also advisable to receive immunotherapy treatment.
Although there is evidence of the effectiveness of the applicability of this combination, finding a doctor who is willing to perform it is a complex process to achieve. Without a doubt, cryoablation should be the first choice, however, it is important to know the radiation characteristics.
One of the main functions of radiation is to cause the immune system to identify malignant cells and destroy them. Radiation can also activate the stimulator of interferon gene pathways (STING), which can stimulate a nonspecific innate immune response. On the other hand, this process can cause the release of FCT-B and VEGF, both are immunosuppressive. In addition, radiation can lower the white blood cell count, a condition that is associated with immune suppression.
There are many studies testing the combination of radiation with immunotherapy. There are still some issues to define: What is the appropriate dose to be administered in radiation therapy? How often should it be administered? Once the radiation process has begun, at what point is it recommended to perform immunotherapy? before, after or during the process? There are conflicting studies regarding these treatment details.
In some cases, patients have not had results with immunotherapy, but later when the radiation process was added, the immune response was activated.
So, there are some real potential benefits, and certainly patients who have not had good results with immunotherapy might want to consider adding radiation processes to help activate the immune response.
Some benefits could be derived from previous traditional cancer treatments such as chemotherapy and radiation associated with an anti-cancer immune response. There are currently numerous studies being carried out. The only factor to consider when it comes to chemotherapy is that most studies focus on the traditional method of administering the maximum tolerated dose. However, science has shown that it is more effective to administer a lower dose, but more frequently. Some doctors offer a low dose, metronomic chemotherapy, however, many of them are not oncologists, so it is advisable to seek appropriate advice.
Also, for a patient with cancer with large tumors, chemotherapy and radiation may be helpful in reducing the tumor burden, so that the immune system can fight it off.
More remains to be learned about when therapy should be administered. For example, studies in mice have shown that cyclophosphamide given before chemotherapy, doxorubicin for example, can stimulate an immune response against cancer, but the reverse suppresses the immune response. These types of findings can be variable depending on the type of cancer and its location, as well as the local immune environment of the tumor, which can significantly affect immune responses.
Although it is still being evaluated, this topic has been discussed at immunology meetings and conferences. There, it is discussed that if the maximum dose chemotherapy is applied first, it can reduce the success potential of the immunotherapy that is carried out later. This is probably related to suppression of the immune response.
Williams, J. (2019, 15th October) The Immunotherapy Revolution. Pg 72-75