The most common surgical treatment is prostatectomy, the removal of the prostate. During prostate surgery, tumor remains at the edge of the surgery, called residual tumor, in 30% of all prostatectomies. Such patients have a significantly higher risk of local recurrence of the cancer, and higher rates of death. In contrast, even patients with cancer outside of the prostate, but still nearby the prostate, do better when the margins are made clean of tumor during surgery.