SBRT Alone or Followed by Niraparib for Oligometastases or Oligoprogression in Ovarian Cancer Following PARPi Therapy

This study tests whether combining targeted radiation therapy (SBRT) to individual tumors with a PARP inhibitor drug called niraparib can control ovarian cancer that has progressed during or after a prior PARP inhibitor therapy. **You may be eligible if...** - You are 18 or older - You have ovarian, fallopian tube, or primary peritoneal cancer - Your cancer progressed while on or after at least 6 months of a PARP inhibitor, which was your most recent treatment - You have a limited number of progressing tumor sites (oligoprogression) **You may NOT be eligible if...** - You have not been previously treated with a PARP inhibitor - Your cancer has progressed widely (not oligoprogression) - You have not had the PARP inhibitor as your last systemic therapy Talk to your doctor to see if this trial is right for you.