Immunohistochemical assessment of lymphatic and blood vessel invasion in T1 urothelial carcinoma of the bladder

Objective. The aim of this study was evaluate the incidence and significance of immunohistochemically assessed lymphatic (LVI) and blood vessel invasion (BVI) in primary T1 urothelial carcinoma of the bladder (UCB) treated with radical cystectomy (RC). Materials and methods. Thirty-two patients with T1 UCB at primary diagnosis were identified who underwent radical cystectomy (RC) subsequently. Of these, 16 (50%) had pT1N0M0 (group I) and 16 (50%) ≥ pT2aN0-3M0 UCB (group II) at RC. The presence of LVI and BVI in transurethral resection of bladder tumor (TURBT) and corresponding RC specimens was assessed using hematoxylin & eosin (H&E) and immunohistochemical (IHC) staining against the lymphatic (D2-40) and vascular endothelium (CD31). Results. At TURBT and RC, none of the patients in group I showed LVI or BVI on H&E and IHC sections. In group II, at TURBT, LVI and BVI were negative on H&E staining in all patients, but detectable by IHC in two patients (13%) and one patient (6%), respectively (p = 0.48 and p = 0.99 compared to group I). At RC, LVI and BVI were detected by IHC in eight (50%) and five (31%) of the 16 patients, respectively (p = 0.002 and p = 0.021 compared to group I). Of these eight and five patients, detection of LVI and BVI was only possible with IHC in six (75%) and three (60%), respectively. Conclusions. Although this hypothesis-generating study did not show a high degree of concordance between TURBT and RC specimens, IHC assessment on a regular basis may increase the detection rates of LVI and BVI at initial diagnosis and improve the selection of those T1 patients who should be offered early radical treatment.