Pembro With Radiation With or Without Olaparib

Pembrolizumab will be delivered via IV at 200mg on day 1 of each 3-week cycle for approximately 12 months. Cycle 1 begins 21 days prior to radiation therapy and cycles 2-17 are administered during and after radiation therapy.

200mg Olaparib will be given twice daily for a total of 3 cycles. Cycle 1 begins 21-days prior to radiation therapy.

Androgen Deprivation Therapy (either LHRH agonist or LHRH antagonist) as per treating physician choice will be allowed within 3 months prior to randomization. Duration is per institutional standards.

Definitive radiation (total dose and fractions) will be dosed per institutional standards. Definitive radiation may include external beam radiation therapy with or without brachytherapy, based on NCCN risk score and as per treating physicians.