Accuracy of urethral frozen section during radical cystectomy for bladder cancer

Our objective was to determine the accuracy of urethral frozen section (FS) by analyzing our clinical experience.

A total of 298 patients undergoing radical cystectomy for bladder cancer with benign or malignant urethral FS were identified between 2000 and 2012. Urethral FS were compared with rereviewed FS to calculate the positive and negative predictive values of the FS. To assess the ability of the positive FS to be cleared with further sampling/resection, FS were then compared with the final urethral margin. The cases of positive urethral FS were then specifically analyzed to assess rates of urethral recurrence and survival.

All negative FS were confirmed to be negative on FS rereview and on final pathology, resulting in a NPV of 100%. Urethral FS were positive in 28 (8.7%) patients, of whom 2 (7%) were negative on FS rereview, yielding a positive predictive value of 93%. Both false positives were because of contamination of detached cancer from the bladder being present in the FS. After additional sampling/resection, the final margin was negative in 13 (46%) patients.

A negative urethral FS reliably identifies individuals for whom urethrectomy is unnecessary and provides robust information for decision-making regarding the safety of orthotopic reconstruction. Nearly half of the patients with a positive FS were ultimately determined to have a negative final margin. Accordingly, we recommend that surgeons and pathologists discuss positive FS findings at the time of surgery and consider whether additional tissue should be analyzed in real time.