Histological Variants of Urothelial Carcinoma Predict No Response to Neoadjuvant Chemotherapy

Platinum-based neoadjuvant chemotherapy (NAC) in muscle-invasive urothelial bladder cancer (MIBC) has been adopted as a standard of care related to better survival outcomes. However, there is a considerable number of patients who do not respond, experiencing toxicity and delay in the surgical treatment. Our aim is to find biomarkers of response that could be easily adopted in the clinical practice.

Between January 2009 and July 2016, 52 patients with MIBC were submitted to radical cystectomy after NAC. A tissue microarray containing 25 cases, who met the inclusion criteria was built for immunohistochemical analysis of Cytokeratins 5/6, 7, and 20, GATA3, Her2, EGFR, p63, p53, Carbonic-anhydrase IX (CAIX), MLH1, MSH2, MSH6, and PMS2. The surgery was performed in a mean time of 58.7 (± 21) days after the end of the NAC. Fisher's exact test was used to analyze the relationship between response (≤pT1) and histopathological and immunohistochemical results and Kaplan-Meier curves were designed for survival analysis.

Ten (40.0%) patients presented response to NAC. Histological variants of the urothelial carcinoma characterized by squamous, sarcomatous/rhabdoid, plasmacytoid, and micropapillary was present in 36.0% and none responded to NAC (P = .002). CAIX was expressed by 53.3% and none responded to NAC (P= .005). Lymph-node metastasis, divergent differentiation, and expression of cytokeratin 5/6 were related to short cancer specific survival.

Histological variants and CAIX immune-expression are biomarkers of nonresponse to NAC of MIBC, and might be easily used in the clinical practice to select patients to be submitted to surgery upfront.