Dr Sameer Sonar, Group Director-Nuclear Medicine, PET CT & Theranostics, Ruby Hall Clinic Group Hospitals explains about the specialised treatment for prostate cancer
PSMA-PRRT (Prostate-specific membrane antigen-targeted Peptide Receptor Radio-ligand Therapy) is a specialised treatment for prostate cancer. It involves the use of a targeted radiation therapy that specifically targets and attaches to Prostate-Specific Membrane Antigen (PSMA), which is found on the surface of prostate cancer cells.
How does peptide therapy work
During the treatment, a radiolabeled molecule (177Lu –PSMA) is administered to the patient, which attaches to the PSMA on the cancer cells. The beta radiation of 177Lu then destroys the cancer cells from within, while minimizing damage to surrounding healthy tissue.
PSMA-PRT is an effective treatment option for men with advanced prostate cancer that has spread to other parts of the body like lymph nodes & bones.
It has been shown to help shrink tumors, alleviate symptoms, and extend survival in patients. PSMA PRRT has shown promising results in patients, studies reporting high rates of response and prolonged survival in patients with advanced prostate cancer.
Types of radiation from radionuclides
There are 3 types of radiations from radioisotopes used in Nuclear Medicine. For the last 50-60 years we have been using Gamma rays for evaluation of function by Nuclear scans of Thyroid, kidneys, bones and blood supply of heart. More recently we started using Beta & alpha rays for “treatment”. These two rays (particles) travel very small distance (few mm to micron) and transfer the energy to cancer cells, causing DNA damage and cell death.
The difference between PSA and PSMA test
Serum PSA is Prostate Specific Antigen in the blood which is an important biomarker and it’s value in the blood is used to track response to therapies & progression. Increasing PSA levels indicate spread of cancer.
PSMA is Prostate Specific Membrane Antigen, which is expressed and is present on cell surface. This can be seen with help of PSMA PET CT scan. These antigens are present in all sites where prostate cancer is spread.