PD33-10 THE PRESENCE OF RESIDUAL CARCINOMA IN SITU ALONE (PTIS) IN PATIENTS TREATED WITH RADICAL CYSTECTOMY DOES NOT AFFECT LONG TERM RECURRENCE AND SURVIVAL RATES

AND OBJECTIVES: Frozen section analysis (FS) of the distal urethral margin is used to determine the feasibility of orthotopic reconstruction or the need for simultaneous urethrectomy in patients undergoing radical cystectomy for the treatment of bladder cancer. Despite the fact that this practice represents the contemporary standard of care, scant data exist upon which to base an evaluation of the accuracy and reliability of urethral FS at the time of surgery. We sought to determine the positive and negative predictive values of urethral FS by analyzing our clinical experience. METHODS: The IRB-approved, institutional urothelial cancer database (2000-2012) was reviewed for patients undergoing radical cystectomy in which FS had been performed to assess distal urethral margins. We compared urethral FS status with that of the final urethral margin section in order to calculate the positive and negative predictive values of the FS. The cases of positive urethral FS were then specifically analyzed to assess rates of urethral recurrence and survival. RESULTS: 750 patients with complete pathologic information underwent cystectomy for bladder cancer at our institution during this period (median follow-up, 36.9 months). Urethral FS were sent in 322 cases (43%). All patients with a negative FS were confirmed to have a negative margin on final pathology, resulting in a negative predictive value of 100%. Urethral FS were positive in 28 patients (8.7%), of which 13 (46%) ultimately had negative margins on final pathology, yielding a positive predictive value of 54%. Of the patients with positive urethral FS, 3 underwent urethrectomy (1 concurrent, 2 delayed). Four patients with positive final urethral margins had urethral recurrences (median follow up 29.1 months). These individuals were subsequently treated with adjuvant chemotherapy (2 patients) and urethrectomy (2 patients). No differences in freedom from urethral recurrence or overall survival were seen between those in whom positive FS remained positive (true positive) and those in whom positive FS became negative on final pathology (false positive). CONCLUSIONS: 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 if practical.