Pathological reporting of cystectomy lymph nodes: a retrospective analysis of experience in Paris

André Oszwald,Laura Larnaudie,Eva Compérat,Philippe Sebe,Justine Varinot,Gabriel Wasinger,Olivier Cussenot

doi:10.1007/s00345-021-03630-8

Abstract

PurposePathological evaluation of pelvic lymph node (LN) dissection (PLND) is important for management of cystectomy patients. However, challenges such as unclear interobserver variability of LN counting remain. Here, we assess interobserver variability of LN measures and their clinical utility, with a focus on variant histology.MethodsWe retrieved radical cystectomy cases with PLND between 2010 and 2016 and reevaluated pathological parameters; number of total and metastatic LN, LN density (LND), length of metastatic LN and metastases, extranodal extension (ENE).ResultsWe report 96 patients: median age of 71a, 34 cases pN+, 36 cases with any extent of variant histology, median follow-up 10 months. Perivesical LN were only rarely identified, but frequently metastatic (4/9). Variant histology (34 cases) frequently exhibited LN metastasis (53% of pN+ cases). Interobserver variance was poor for total LN (kappa = 0.167), excellent for positive LN (0.85) and pN staging (0.96), and mediocre for LND (0.53). ROC analysis suggests that both LND and the sum of LN metastasis length may predict outcome (AUC 0.83 and 0.75, respectively).ConclusionOur study confirms the notion of LND as a prognostic measure, but cautions due to strong interobserver variance of LN counts. The sum length of LN metastases could be a measure that is independent of LN counts. We find that microscopically identified perivesical LN merit particular attention. In summary, our study highlights current challenges in pathological reporting of PLND, confirms previous observations and forms a basis for further studies.

Highlights

Radical cystectomy (RC) with pelvic lymph node dissection (PLND) is the standard treatment of urothelial carcinoma (UC) in muscle-invasive bladder cancer (≥ pT2) [1] and a viable option for Bacillus Calmette–Guérin (BCG)AP‐HP, Tenon Hospital, Sorbonne University, 75020 Paris, France refractory non-muscle-invasive UC or carcinoma in situ [2, 3]
Positive LN counts were significantly higher in non-limited templates than in limited templates (medians and ranges: 0 (0–9) vs 2.5 (0–10), p = 0.02)
We found that LN density (LND), positive LN count and total length of LN metastases were good predictors of outcome (AUC 0.83, 0.79, and 0.75, respectively)

Summary

Introduction

Radical cystectomy (RC) with pelvic lymph node dissection (PLND) is the standard treatment of urothelial carcinoma (UC) in muscle-invasive bladder cancer (≥ pT2) [1] and a viable option for Bacillus Calmette–Guérin (BCG)AP‐HP, Tenon Hospital, Sorbonne University, 75020 Paris, France refractory non-muscle-invasive UC (pT1) or carcinoma in situ [2, 3]. Pathological societies have recommended reporting extranodal extension (ENE) and the greatest diameter of lymph node metastases [5] Taking into account these and other details could result in more accurate staging and stratification. An unresolved challenge is the significance of lymph node counts in regard to patient management, which has recently been questioned [6] Another controversial measure is the lymph node density (LND, ratio of positive LN to total LN), claimed to predict prognosis and better stratify LN-positive patients [7]. A further issue is a frequently requested minimum number of LN for diagnosis All these measures suffer from the lack of established standards in gross handling, counting, and reporting of PLND specimens [8,9,10]

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