Predicting biopsy-proven prostate cancer recurrence following cryosurgery

Prostate cancer (CaP) cryosurgery utilizes PSA nadir level and radiotherapy criteria as surrogates for success. We attempted to correlate PSA doubling time (PSAdt) and time of undetectable PSA (TUPSA) with biopsy-proven cancer recurrence (BPR) in men treated with primary third-generation cryotherapy for clinically localized CaP.

Demographic, clinical, and pathologic data was retrieved including age, race, use of preoperative hormones or 5-α reductase inhibitors (5-ARIs), initial biopsy PSA, biopsy Gleason score, cT stage, prostate volume, presence/absence median lobe, and follow-up. Post-cryotherapy biopsy was considered for PSA levels ≥ 0.5 ng/ml. PSAdt was determined by the log-slope method. TUPSA was defined as time from surgery to a PSA value ≥ 0.2 ng/ml or most recent follow-up if undetectable.

Ninety-seven patients were identified. Preoperative hormonal manipulation was used in 25 (26%); 5 (5%) were using a 5-ARI. Twenty-seven (29%) underwent post-cryotherapy biopsy, 12 (12%) had a BPR. In 41 (42%), PSAdt was calculated (median 11.9 months, IQR 6.6-34.8); no significant difference between patients with BPR and without CaP was found (P = 0.46). TUPSA was a median of 4.9 months (IQR 3.2-9.9) vs. 15.6 months (IQR 6.1-30.3) for BPR or no CaP, respectively (P = 0.005). On proportional hazards regression, TUPSA was the only independent predictor of BPR (P = 0.03, OR 0.91).

Post-cryosurgery PSAdt does not appear to be associated with BPR risk, whereas TUPSA reduces the risk of BPR by 9% per month. This may help guide management if local failure is suspected.