A podium presentation by Kingman et al. at the upcoming annual meeting of the American Urological Association (AUA) may be among the most significant to be presented at the meeting. It seriously challenges the long-held belief about the need to routinely re-biopsy men initially diagnosed with high-grade prostatic intraepithelial neoplasia (HG-PIN).
According to Kingman and his colleagues (see abstract no. 1242 in the abstracts of the AUA meeting), prostate cancer has, historically, been reported on re-biopsy in 21 to 48 percent of patients initially diagnosed with HG-PIN alone on an earlier prostate biopsy. Kingman et al. set out to determine the incidence of HG-PIN and the correlation of a diagnosis of HG-PIN to a later diagnosis of prostate cancer in a large, contemporary patient population. To do this, the authors conducted a retrospective review of their pathology database to identify all patients diagnosed with isolated HG-PIN between 2001 and 2011. These patients were then evaluated with regard to subsequent outcome, specifically identifying those with subsequent biopsies and the diagnosis of prostate cancer.
Here are the study findings:
- 6,101 prostate biopsies were performed and identified 614 discrete individuals with isolated HG-PIN who had no previous abnormal prostate biopsies.
- The average (median) PSA of patients at the time of diagnosis of isolated HG-PIN was 5.5 ng/ml.
- Average (median) follow-up was 38.6 months.
- 393/614 patients (64 percent) had at least one subsequent biopsy.
- Prostate cancer was found in 140/614 patients (22.8 percent) in total, which equates to 140/393 patients (35.6 percent) who had a subsequent biopsy.
- The average (median) PSA levels of the 393 patients who had a re-biopsy were
- 8.05 ng/ml among the patients who were positive for cancer at re-biopsy
- 6.4 ng/ml among the patients who did not demonstrate progression to prostate cancer
- This difference was statistically significant (p = 0.016).
- Among the 140 patients found to have prostate cancer at a subsequent biopsy,
- 115/140 patients (82 percent) had a primary Gleason grade of ≤ 3.
- 22/140 patients (16 percent) had a primary Gleason grade of 4.
- 3/140 patients (2 percent) had a primary Gleason grade of 5.
- 86/140 patients (61 percent) had a Gleason score of ≤ 6.
- 46/140 patients (33 percent0 had a Gleason score of 7
- 8/140 patients (6 percent) had a Gleason score of ≥ 8.
- Average (mean) PSA levels among the 140 patients at time of diagnosis with cancer were
- 10.3 ng/ml among patients with primary Gleason grades of 4 or 5
- 7.6 ng/ml among patients with primary Gleason grades of 3 cancer.
- This difference was not statistically significant.
- There was no statistical difference between the patients who did or did not go on to develop cancer based on whether they had bilateral or unilateral HG-PIN on the initial identifying biopsy.
Kinman et al. conclude that, in one of the largest cohorts of HG-PIN patients reported to date,
- The subsequent incidence of cancer incidence was similar to that reported with initial PSA-driven biopsies.
- The extent of HG-PIN (unilateral versus bilateral) did not appear to correlate with a greater risk of developing prostate cancer.
Based on this information, they argue that, consequently:
- HG-PIN does not have a higher predictive value for subsequent cancer than PSA alone.
- The previous diagnosis of HG-PIN did not predict for higher-grade cancer.
This leads us to the not unreasonable conclusion that the decision to re-biopsy men with an initial finding of HG-PIN should not be routine at all, but should be premised solely on a continuing rise ion the patient’s PSA level.