Abstract: Background and purpose: High intensity focused ultrasound (HIFU) can be effective in the treatment of prostate cancer, however cancer is a systemic disease, the treatment method is not only resect local tumor in no damage to normal tissue but also activate the body’s anti- tumor immune response. This paper aimd to explore the effect of HIFU treatment on the body anti-tumor immunity of intermediate and advanced prostate cancer patients after castration. Methods: Forty patients with intermediate and advanced prostate cancer were randomly divided into 2 groups. Twenty were treated by HIFU after 2 weeks through castration and the other 20 had sole castration as control group, all patients diagnosed by transrectal prostate biopsy pathology and identified as advanced prostate cancer, prostate specific antigen (PSA)>20 ng/mL. Patients accepted the HIFU therapy and signed the informed consent. The average ages of HIFU and the control group patients were (72.56+12.38) and (75.23+9.35) years old (P=0.446 3) and the mean levels of initial PSA were (105.22+20.55)ng/mL and (100.53+18.38)ng/mL (P=0.451 5). We collected the venous blood before and after all treatment in the intervals of 2 weeks. Test items included T lymphocyte (CD4⁺, CD8⁺, CD4⁺/CD8⁺) and Th cell factor (IFN-γ, IL-2, IL-4, IFN- IL-10). Results: In the HIFU-treated patients, the percentage of CD4⁺ and CD4⁺/CD8⁺ ratio increased significantly after treatment; IFN-γ, IL-2 were significantly increased, while IL-4 and IL-10 were decreased significantly, the difference was statistically significant (P<0.05), Th1/Th2 balanced to Th1 drift. The control group had no significant difference in each index between before and after treatments (P>0.05). HIFU treatment group had significant difference in each index between before and after treatments (P<0.05). Conclusion: HIFU treatment can improve the body anti-tumor immunity of intermediate and advanced prostate cancer patients after castration.

Key words: High intensity focused ultrasound, Prostate cancer, Immunology