Immunotherapy as a Precision Medicine Tool for the Treatment of Prostate Cancer

SIMPLE SUMMARY: Immunotherapy has emerged as an attractive alternative to conventional therapies for the clinical management of prostate cancer (PCa); it not only specifically targets malignant cells while protecting healthy tissue, but it also appears to augment the therapeutic effect of existing treatments when used in combination. The identification of biomarkers with prognostic and preventive clinical significance has facilitated the incorporation of immune-targeted agents in clinical trials, with the aim to assess therapeutic efficacy in patient sub-populations that have been stratified on the basis of specific molecular traits and prognostic variables. This perfectly fits the rationale of precision medicine, which aims to match patients with targeted therapies so as to achieve the maximum clinical benefit. The numerous clinical trials currently evaluating multiple immunotherapeutic approaches in PCa patients, both alone and in combination with other treatments, offer much hope for achieving significant advances in the decision for precision treatment of the disease. ABSTRACT: Prostate cancer (PCa) is the most frequently diagnosed type of cancer among Caucasian males over the age of 60 and is characterized by remarkable heterogeneity and clinical behavior, ranging from decades of indolence to highly lethal disease. Despite the significant progress in PCa systemic therapy, therapeutic response is usually transient, and invasive disease is associated with high mortality rates. Immunotherapy has emerged as an efficacious and non-toxic treatment alternative that perfectly fits the rationale of precision medicine, as it aims to treat patients on the basis of patient-specific, immune-targeted molecular traits, so as to achieve the maximum clinical benefit. Antibodies acting as immune checkpoint inhibitors and vaccines entailing tumor-specific antigens seem to be the most promising immunotherapeutic strategies in offering a significant survival advantage. Even though patients with localized disease and favorable prognostic characteristics seem to be the ones that markedly benefit from such interventions, there is substantial evidence to suggest that the survival benefit may also be extended to patients with more advanced disease. The identification of biomarkers that can be immunologically targeted in patients with disease progression is potentially amenable in this process and in achieving significant advances in the decision for precision treatment of PCa.