Understanding the Abscopal effect in Prostate Cancer – Primary and Metastatic Tumour Crosstalk

When a man with prostate cancer has his primary tumour treated with surgery or radiotherapy, that treatment may also trigger an immune response against cancer cells that have already spread to other parts of his body. This study will investigate that phenomenon—called the abscopal effect—by comparing how the genome, gene activity, and drug sensitivity of metastatic tumours change depending on whether the primary tumour was removed surgically or irradiated, versus standard care. The problem is that many men with prostate cancer either already have metastases at diagnosis or develop them quickly, and those secondary tumours eventually become resistant to treatment and lethal. Doctors currently have little evidence to guide which primary treatment best slows or prevents that transition to therapy resistance. If this research succeeds, it could change how clinicians tailor initial treatment for men with metastatic prostate cancer—choosing surgery or radiotherapy based on which one better suppresses secondary tumour growth. The findings would also provide a foundation for developing new drugs that target the mechanisms driving therapy resistance in advanced disease.