Incidence of occult lymph-node metastasis missed by standard pathological examination in patients with bladder cancer undergoing radical cystectomy.

Objective: The aim was to conduct an exploratory study of the ability of standard pathological examination (SPE) of lymph nodes (LNs) to detect metastasis in LN specimens from patients with bladder cancer undergoing radical cystectomy (RC).

Material and methods: From a cystectomy database, 10 LN-negative patients with invasive bladder cancer were randomly selected based on their Tstage (two T1, four T2 and four T3). LN specimens were step sectioned and stained by immunohistochemistry to identify occult metastases missed by the SPE.

Results: In total, 173 LNs negative by SPE were investigated. Metastasis was identified in one LN in one patient with non-organ-confined disease. No other positive LNs were found. Thus, SPE had a negative predictive value of 99.4% per LN (95% confidence interval CI96.8?99.99%) in this small series.

Conclusions: Occult nodal metastasis can be overlooked by SPE in a minority of patients undergoing RC because of bladder cancer. This is presumably more likely in patients with non-organ-confined tumours because of a higher risk of LN metastasis in this patient category. Therefore, the importance of a thorough LN dissection in presumably LN-negative patients is emphasized. However, the number of patients in the present study is too low for conclusions to be drawn regarding the true frequency of occult LN metastases.