Is transurethral resection alone enough for the diagnosis of histological variants? A single-center study.

INTRODUCTION: To evaluate incidence of histological variants and grade agreement between transurethral resection (TUR) and radical cystectomy (RC) in patients with bladder cancer.

METHODS: A total of 779 patients treated with TUR and subsequently with RC between 1990 and 2013 at a single center were analyzed retrospectively. Variant histology classifications used in our analyses were sarcomatoid, small cell, squamous, or micropapillary. Grade agreement was calculated using the Cohen kappa coefficient. Logistic regression analyses were built to predict adverse pathologic features from histological variants at TUR.

RESULTS: Considering TUR, 213 (27.3%) patients were diagnosed with histological variants. Of these, 2.1% (n = 16) were found with sarcomatoid variant, 1.7% (n = 13) with small cell, 7.1% (n = 55) with squamous, 12.5% (n = 97) with micropapillary. Considering RC, 212 (27.2%) patients were diagnosed with histological variants. Poor agreement was found considering micropapillary variant and the presence of a histological variant in general (0.11 and 0.27, respectively). Intermediate agreement was found analyzing the presence of sarcomatoid, small cell, and squamous variants (0.43, 0.61, and 0.61, respectively). Small cell carcinoma at TUR was found associated with an increased risk of harboring positive soft tissue surgical margin (odds ratio = 2.08; CI: 1.27-3.41; P = 0.03).

CONCLUSIONS: One out of our patients with bladder cancer was diagnosed with a histological variant either at TUR and RC. We found poor agreement between TUR and RC. Our findings highlight that TUR alone is not sufficient to accurately evaluate the presence of histological variants that may have an effect on treatment and survival outcomes.