Radioligand fOr locAl raDiorecurrent proStaTe cancER

Surgery or radiation are common treatments for a prostate cancer that is confined to the prostate gland itself. After radiation treatment, a significant minority of patients (about one third) progress with cancer persistence or cancer regrowth (also known as local recurrence). Patients with local recurrent prostate cancer are eligible for additional treatments directed at the prostate. Prostate Specific Membrane Antigen (PSMA) is protein that is present in high quantities on prostate cancer and radioactive chemical "probes" against PSMA can identify those men with prostate cancer recurrence that is isolated to the prostate. These radioactive probes can also be used to treat prostate cancer using high energy radioactive materials such as 177-Lutetium (Lu). A standard of care for the treatment of locally recurrent prostate cancer is the use of internal radiation (brachytherapy) delivered through needles inserted into the prostate from the outside. While brachytherapy allows high repeat doses of radiation to be given to the prostate and cancer, there is the potential to injury nearby structures such as the bladder and rectum. 177-Lu PSMA potentially provides a way to give an even more focused treatment to the cancer in the prostate (as well as treat any microscopic cancer that might be outside the prostate). In this study we will test the safety of integrating 177-Lu PSMA into the treatment of locally recurrent prostate cancer in combination with brachytherapy. A total of 6 men per group (total=12) will be used in the first phase of this project to establish feasibility and safety of the combined treatment. Eligible participants will be chosen randomly to get one cycle of 177-Lu-PSMA treatment followed by brachytherapy treatment or the standard treatment of two brachytherapy treatments without 177-Lu-PSMA. All men will have biopsies (a small piece of tissue) and blood and urine samples taken at the time of the second brachytherapy treatment to compare markers of radiation effect from the first treatment with either 177-Lu-PSMA or brachytherapy. Toxicity assessment and Quality of Life questionnaires will be done at 6 weeks and 6 months after treatment to determine safety. Feasibility will be determined by the proportion of men in whom the treatment is delivered as planned. Provided safety and feasibility are established with the first 12 men, the study will continue to include 15 men per arm (30 men in total). By developing a new treatment option for men with local recurrence after radiation, ROADSTER will be impactful for this group of men where existing treatments can carry significant side effects and are successful only about half the time. ROADSTER trial is designed to involve two of the Lawson programs i.e. Imaging and Cancer and the trial participants will be treated in both departments. This inter-disciplinary collaboration is the key to answer the study question.