Multicenter retrospective trial of impact of androgen deprivation therapy on immune phenotype in localized prostate cancer

Androgen deprivation therapy (ADT) for localized prostate cancer suppresses testosteron and tumor cell growth, and emerging evidence suggests that ADT also can modulate the immune tumor microenvironment (TME). In a multicenter retrospective study researchers analyzed primary prostate cancer, comparing those surgically removed either without treatment or following treatment with degarelix at 4, 7, and 14 days pre-surgery. The study showed that ADT rapidly transforms the typically bland prostate TME into an inflamed environment within days. ADT resulted in an increase in activated CD8 T-cells along with an increase in suppressive regulatory T-cells (Tregs). There also was en expansion of the myeloid compartment, particularly pro-inflammatory M1-like tumor-associated macrophages. In the tumor cells, ADT resulted in upregulation of antigen presentation by MHC class I and II and, unexpectedly, a decrease in the “don’t eat me” signal CD47. The authors conclude that ADT drives a distinct immune phenotype in localized prostate cancer.