Bladder Preservation for Patients With Muscle Invasive Bladder Cancer (MIBC) With Variant Histology

Trimodal therapy (TMT) is accepted as an NCCN category 1 alternative to radical cystectomy (with neoadjuvant chemotherapy) in patients with cT2N0M0 muscle-invasive urothelial cell bladder cancer (MIBC). Not all patients with MIBC have pure urothelial cell carcinoma; urothelial carcinoma with variant histology (VH) described any morphologic variant of conventional urothelial carcinoma that is believed to be derived from urothelial carcinoma and is typically admixed with conventional urothelial carcinoma in the same tumor. Variant histologies described include squamous differentiation, glandular differentiation, micropapillary, sarcomatoid, small cell/neuroendocrine, plasmacytoid and nested variant. This is a rare tumor type and understudied. For patients with variant histologies there is limited data on the use of trimodal therapy. There are a couple single institution retrospective studies and data from the NCDB, but no prospective data.