means that there are cancer cells at the edge of tissue that has been removed. This can only be seen under the microscope, after the surgery. Positive margins occur about
25-35% of the time after non-nerve sparing radical prostatectomies and 35-45
% of the time in nerve sparing radical prostatectomies. Positive margins mean the chance of the cancer recurring in the surgical area is significantly greater than if the margins are negative.
An undetectable PSA is PSA 0.2 ng/ml or lower, which essentially means a “zero” PSA. PSA 0.2 ng/ml means undetectable because PSA tests are unreliable below 0.2 ng/ml. Johns Hopkins defines it as less than 0.2 ng/ml. The Prostate Cancer Research Institute (PCRI) defines it as "a PSA of <0.05 using a hypersensitive assay such as DPC Immulite 3rd generation PSA or Tosoh assay." From a strict technical point of view, an "undetectable" reading is one where the equipment failed to detect the marker sought, PSA in this case.