Distribution and retention of autologous leukocytes after their injection into the prostatic venous plexus of patients with prostate cancer

Abstract

Prostate cancer (PC) is the second leading cause of cancer death in men. Surgical removal of the prostate together with the tumor prolongs the patient’s life but often impairs their quality of life. Therefore, developing methods for the organ-sparing treatment of prostate cancer is very relevant. Immunotherapy based on reprogrammed immune cells could accomplish this task. However, the problem is that the injected cells can quickly leave the tumor area through the channel made by the syringe needle, through blood or lymphatic vessels, and, therefore, would not remain in the tumor for a sufficient time to exert their therapeutic effect.

The aim of this study was to assess the distribution and retention of autologous leukocytes in the prostate gland after their local injection into the prostatic venous plexus in patients with prostate cancer.

Methods. The study was performed a few days before the elective robot-assisted radical prostatectomy in patients with prostate cancer. A buffy coat layer (BCL) was obtained from venous blood of the patient. Cells were labeled with 99mTc-Pertechnetate eluate. The labeled cell concentrate (radiopharmaceutical, RF) was injected into the patient's prostate. After the RF injection, SPECT/CT and scintigraphy were performed in the whole-body mode at 30 min, 12 h, and 24 h.

Results. In all patients at 24 hours, almost 50% of the injected RF radioactivity remained in the prostate projection. Furthermore, the time-related decrease in the RF radioactivity displayed two patterns, i) a slight decrease in the first 12 h followed by a rapid decrease in the next 12 h and, vice versa, ii) a rapid decrease in the first 12 h followed by a slight decrease in the next 12 h.

Conclusion. A method has been developed for managing the distribution of cell preparations within the human prostate. Patients well tolerated the procedure of injection of labeled cell into the prostatic venous plexus. These results laid a good foundation for the development of a technology of immunotherapy for PC based on immune cells.