AUA 2018: Local Immune Modulation by Decreasing CD4+/CD8+ T Cells Ratio after Prostate Cancer Hemi-Cryoablation

San Francisco, CA (  Leonardo Reis MD, and colleagues sought to answer a unique question with regard to the effect of thermal ablation on prostate immune infiltrates following therapy. Thermal ablation is known to increase antigen presentation, thereby possibly activing tumor-specific T cells, but little is known about the immune response within the local prostatic environment.

They, therefore, studied 10 patients who underwent unilateral prostate cryoablation to compare immune cell infiltrates within treated tissue against non-treated tissue from each patient. Tissue was obtained via biopsies after recovery from hemi-cryoablation. They found a significant increase in the number of CD8+ T cells within cryoablated prostate compared to the non-treated tissues. In contrast, CD4+ T cell concentrations tended to decrease in cryoablated tissue vs. non-treated tissue. The ratio of CD4+/CD8+ T cells decreased after hemi-cryoablation.

This is the first study to evaluate the effect of thermal ablation on T-cell infiltrates within the prostate. Given our growing understanding of how immune mechanisms might be responsible for oncological outcomes, this research is an important addition to our knowledge base. Hopefully, these findings can be leveraged to find therapies that capitalize on immune cell infiltration and can also be used in combination with thermal ablation.

Presented by: Leonardo Reis, MD, MSc, PhD, Pontifical Catholic University of Campinas - PUC-Campinas, Brazil
Co-Authors: Michael A. Cerqueira, Karen L. Ferrari, Amilcar C. de Mattos, Leonardo Reis*, Campinas, Brazil

Written by:  Shreyas Joshi, MD, Fox Chase Cancer Center, Philadelphia, PA, @ssjoshimd at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA
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