blood in urine

What could cause microscopic blood in urine of a 73 year old male who had a seed implant proceedure on my prostate (4) four years ago?  Uroflow tests appear consistant (4-5 tests made over the past 4 years), and I'm not getting up at night more than once or twice to urinate...depends on whether I take in fluids after 6:00PM. Dr. did a uroflow a month ago and said it looked "flat" and I don't think he referred to the previous reults to compare.  And, prior to seeing the "blood" -  which I cannot see with the naked eye - he recommended a cystocopy to look for "bladder cancer".  I'm concerend about getting un-necessary tests that are not very pleasant to experience. The nurse said he's looking for a stricture or blockage and the doctor is attempting to rule out bladder cancer.  I think the prostate proceedure (seeds) was successful and I would recommend it if your doctor suggests it as one alternative.  Last month my 76 year old brother had his prostate radiated (external) for the first time and he has another week of treatments to go, (15 min. a day, five days a week for a total of five weeks)