Metastatic prostate cancer means that the cancer has spread beyond the prostate gland and nearby tissues to other distant body areas, such as the bones and distant lymph nodes. Prostate cancer may also spread to other organs such as the lungs, liver and brain, but the bone and lymph nodes are more common sites for metastatic disease.
A very small percentage of men, about 5 to 7%, have metastatic disease at the time of diagnosis. Some men go on to develop advanced or metastatic disease after treatment for early-stage prostate cancer.
While no treatments can cure metastatic prostate cancer, advances in treatment over the last decade have helped to significantly extend survival and relieve symptoms.
Treatment for metastatic prostate cancer
There has been tremendous progress in the treatment of metastatic prostate cancer over the last decade and long-term median survival has doubled. Your treatment may include:
- Drugs to block testosterone. Initial therapy of metastatic prostate cancer involves androgen-deprivation therapy using a combination of two types of drugs to block testosterone: luteinizing hormone-releasing hormone (LHRH) therapy given by injection to injections to block testosterone produced from the testes and androgen receptor (AR) targeted therapy given in oral pills block testosterone from other sources in the body.
- Triple therapy for metastatic prostate cancer. In patients with high-volume metastatic disease (a greater amount of disease has spread to lymph nodes, bone and other organs) adding the chemotherapy drug docetaxel to the LHRH therapy and AR targeted therapy is recommended. This so called “triple therapy” was recently approved based on two important clinical trials known as the PEACE-1 and ARASENS trials. They determined that the double therapy extends survival by 30%, but in high-risk and high-volume disease, triple therapy extends survival by another 20%.
- PARP inhibitors. This type of targeted therapy works to prevent the PARP protein from helping cancer cells repair themselves. (We want damaged cancer cells to die off rather than be repaired.) These drugs are most effective against tumors that already have a faulty “repair” gene. Men are deemed to have castrate resistant prostate cancer (because the androgen deprivation therapy stopped working) should have DNA testing of their tumor to determine if they are candidates for PARP inhibitors (such as olaparib and rucaparib).
- Checkpoint inhibitors. These drugs are a type of immunotherapy, and work to use the body’s immune system to fight against the cancer. Some cancers have certain gene mutations or have cancers that express the protein PD-L1. An immunotherapy called pembrolizumab (Keytruda) may help the immune system better attack cancer cells that have these mutations or PD-L1 protein.
More about checkpoint inhibitors
- Second-line chemotherapy. Some patients may begin second-line chemotherapy with another chemotherapy drug called cabazitaxel.
- Radiopharmaceutical drug. A new radiopharmaceutical drug called lutetium Lu 177 vipivotide tetraxetan (Pluvicto™) carries a radioactive substance (isotope) to prostate cancer cells that have a biomarker called prostate-specific membrane antigen. The drug attaches to and is absorbed by the PSMA-positive cells where the drug then releases radiation that can damage and kill the cells. Your physician team will determine whether your prostate cancer cells are PSMA-positive with a specialized PSMA-PET scan. Pluvicto is used for patients with metastatic castration-resistant prostate cancer that is PSMA-positive. It is administered as an intravenous infusion, every six weeks for a maximum of six treatments.
The exact order of treatment for men with castration resistant prostate cancer is currently unclear. However, it is not uncommon for men to sequentially go through most of the above treatments.