The Accuracy of Sequential Urethral Frozen Section and its Impact on Urethral Recurrence After Radical Cystectomy

To assess the accuracy of frozen section analysis (FSA) for detecting and eliminating malignant urethral margins during radical cystectomy (RC) for bladder cancer (BC) and its impact on urethral recurrence.

Urethral margins were initially examined by FSA in 217 patients at RC. When positive, additional resections were performed. Subsequently, all specimens were re-examined on formalin-fixed, paraffin-embedded sections (FFPE). Malignancy was defined as either the presence of carcinoma in situ, high-grade or invasive tumor cells at the urethral margin. Kaplan-Meier analysis was used to assess the impact of the final urethral margin status on urethral recurrence. Multinomial logistic regression addressed independent risk factors for a positive final urethral margin.

At initial examination, urethral margins were positive on FSA and FFPE in 21 (9.7%) and 17 (7.8) patients, respectively. The corresponding sensitivity, specificity, positive and negative predictive values were 88.2%, 97.0%, 71.4% and 99.0% (overall accuracy: 96.3%). After initial FSA, 23 patients (including 2 with equivocal histological findings) received re-resections (median: 1, total range: 1-3). Persistent positive margins were detected on FSA in 10 (43.5%) while none of these margins were positive on FFPE (overall accuracy: 52.2%). A positive urethral FSA at initial assessment was the only independent risk for a positive final urethral margin. The 3-year urethral recurrence-free survival was 99.1% for patients with negative margins on initial assessment (I), 100% for those with negative final margins after re-resection (II) and 83.3% for patients with positive final margins (III; P= .013 for I/II vs. III).

The accuracy of FSA for detecting malignant urethral margins is high on initial examination but drops considerably in case of re-resection while most positive margins at initial FSA are converted to negative final ones on FFPE. Conversion of a positive to a negative margin was associated with a lower risk of urethral recurrence.