Precision medicine – in which treatment is individualized to the biology of a particular patient’s cancer – has already become a reality for some patients with prostate cancer. Information obtained from genetic sequencing and molecular imaging are both ways of learning more about the biology of prostate cancer. Oncologists use this information to craft a precision medicine approach towards cancer treatment. Because of this, consensus guidelines now recommend that all patients with metastatic prostate cancer should have genetic testing.
Prostate Cancers with Mismatch Repair Deficiency
Genetic sequencing can be used to identify specific genetic subtypes of prostate cancer, one of which is prostate cancer with a mutation in a family of genes involved in DNA mismatch repair. Cancers with a mutation in this family of genes develop extensive DNA damage, making the cancer look foreign to the body, akin to an infection. These cancers often respond exquisitely to immunotherapy. Nivolumab and Pembrolizumab are two FDA approved checkpoint immunotherapies for this type of prostate cancer.
Prostate Cancers with Homologous Recombination Deficiency
A different type of genetic mutation, in the BRCA2 and related genes, is emerging as another important development in prostate cancer. Again, genetic sequencing must be done to determine if there are mutations in these genes. If the genetic mutation is identified, there are multiple clinical trials – available at academic medical centers – with a class of drugs called PARP inhibitors that are available. These PARP inhibitors have already shown impressive anti-cancer activity and are FDA approved for patients with ovarian and breast who harbor these genetic mutations.
Targeting Prostate Cancer with PSMA Radioligand Therapy
Yet another precision treatment is being rapidly developed for prostate cancer. Rather than targeting a specific gene mutated in a subset of prostate cancer, this treatment targets the presence of something called prostate specific membrane antigen (PSMA). PSMA is a protein that coats the surface of up to 80% of advanced prostate cancers. This treatment known as a radioligand therapy acts like a smart bomb by recruiting the radioactive payload selectively to cells coated with PSMA. This treatment is currently in phase 2 and phase 3 studies.