- For patients with no measurable disease, a positive bone scan and elevated PSA will be required. PSA evidence for progressive prostate cancer consists of a PSA level of at least 2 ng/ml, which has risen on at least 2 successive occasions, at least 1 week apart. If the confirmatory PSA (#3) value is not greater (i.e., #3b) than the screening PSA (#2) value, then an additional test for rising PSA (#4) will be required to document progression