LIMITS OF TRANSURETHRAL RESECTION IN DETECTING UNCOMMON HISTOLOGICAL VARIANTS WITHIN BULKY BLADDER TUMORS IN REAL-LIFE CLINICAL PRACTICE

INTRODUCTION AND OBJECTIVES: Rare histotypes representalmost 10% of bladder tumors, more often represented withinlarge and muscle invasive transitional cell carcinomas of the bladder(MIBC). Neoadjuvant chemotherapy is recommended (Grade A) byinternational guidelines. Rare histological variants, more aggressiveand less responsive to systemic chemotherapy might remain unrecognizedat initial transurethral resection (TURBT) in everyday clinicalpractice. We investigated the accuracy of TURBT in detecting rarehistological variants in patients with large bladder tumors candidate tocystectomy.METHODS: The clinical and pathologic data of 540 patientssubmitted to TURBT and/or cystectomy for bladder cancer betweenJan. 2010 and Oct. 2016, were reviewed. The presence of uncommonhistotypes within urothelial bladder carcinoma has beenassessed. Rare variants were diagnose according WHO criteria.Standard hematoxilyn-eosin stain was adopted and further immunohistochemistrywas performed. Inferential statistical analysis wasperformed.RESULTS: Out of 540 patients, 43 (7,9%) showed rare histotypesof bladder cancer. In 5 (11,6%) cases the uncommon histotypeswas revealed by palliative TURBT . The remaining 38 patients weresubmitted to cystectomy for bladder tumors of considerable size (meandiameter 7,8 cm; range of 5-11 cm); 14 (36,8%) harbored a pT4 tumor.The rare histotypes were: squamous carcinoma 6 (13,9%), sarcomatoid2 (4,8%), undifferentiated 5 (11,6%), neuroendocrine 3 (6,9%), mixed27 (62,8%). TUR revealed an uncommon histotypes in 26 (68,4%)cases only. Moreover, in 5 (23.8%) patients an additional uncommonhistology not detected by previous TUR, was demonstrated in cystectomyspecimens.CONCLUSIONS: The prognostic role of uncommon histotypesin bladder cancer is well documented. Unrecognized rare histotypesmight have important therapeutic implications since possibly lessresponsive to neoadjuvant chemotherapy. These patients could benefitfrom an immediate cystectomy avoiding neo-adjuvant chemotherapy.The inaccuracy of TUR in everyday clinical practice in detectinguncommon variants could be explained by an inadequate samplingof large tumors. The 00pre-cystectomy00 TUR is often performed onlyto confirm the infiltration. As a matter of fact, the pathologists mightnot receive an adequate amount of tissue. To standardize theTURBT strategy including sampling of different areas of bulky tumorscould be of clinical value in patients undergoing neoadjuvantchemotherapy.