Improvement of the body's own immune system by IRE
Every patient who has prostate cancer also has cancer cells outside his prostate that can be found in places such as his blood. They are usually destroyed by the patient's immune system. The immune system's scavenger cells (phagocytes) recognize the tumor cells by the tumor-specific proteins on their surface.
Release of tumor proteins during IRE activates the immune system
During IRE treatment, the destruction of the tumor cells causes a massive release of tumor proteins. These proteins are not altered by the IRE procedure, contrary to thermoablation procedures, in which proteins are denatured, i.e. destroyed. Through the lymphatic system, the proteins arrive in the lymph nodes around the prostate, there resulting in an increased immune reaction to the cancer cells remaining in the body.
As early as 1982, Tanaka was able to demonstrate that this tumor-specific immunological effect can lead to a fight against micrometastases in lymph nodes and other organs. A study by Robert E. Neal shows this effect to be also highly relevant in a mice tumor model.
Conclusive data on immunomodulation are already available from the treatment of prancreatic carcinomas with IRE: He, Chaobin, et al. "Immunomodulatory Effect after Irreversible Electroporation in Patients with Locally Advanced Pancreatic Cancer." Journal of Oncology 2019 (2019). https://www.hindawi.com/journals/jo/2019/9346017/abs/
Regression of lymph node metastases after IRE
We have experienced similar developments here. After IRE, patients with lymph node metastases presented a significant regression in the effects on the lymph nodes.
For example, this 65-year-old man with stage T4b N3 prostate cancer. In the image on the left, an enlarged lymph node that shows all signs of malignancy can be seen very clearly. As early as nine days after the IRE treatment of the entire prostate, which was classified as palliative, the lymph node no longer shows any signs of malignancy (middle image). This lymph node (and all of the other lymph nodes not shown here) became significantly smaller. To this very day, there is no sign of a recurrence or bone metastases (right image). Hormone therapy for palliative use has not yet become necessary.