Urachal Carcinoma of the Bladder: Impact of Clinical and Immunohistochemical Parameters on Prognosis.

ABSTRACT

PURPOSE: Urachal carcinoma of the bladder is a rare malignancy. Its histological phenotype is similar to that of primary bladder and colorectal adenocarcinoma. The aim of this study was to explore the expression and prognostic relevance of 6 select protein markers of urachal carcinoma of the bladder, including p53, Ki67, RHAMM, BGN, IMP3 and MMP-7, which were formerly shown to be prognostic in urothelial carcinoma and colorectal adenocarcinoma. MATERIALS AND METHODS: Clinical and followup data were obtained on a total of 26 patients with urachal carcinoma of the bladder treated at 2 university hospitals. Immunohistochemical analysis of p53, Ki67, RHAMM, BGN, IMP3 and MMP-7 expression was performed in samples from 15 patients. Clinicopathological parameters and immunohistochemical results were tested for prognostic value on univariable and multivariable analyses. RESULTS: Followup was 50 months. Five-year overall and progression-free survival was 46% and 32%, respectively. On multivariable analysis a positive resection margin was an independent predictor of poor overall survival (p = 0.025). RHAMM (p = 0.0431), IMP3 (p = 0.0052), Ki67 (p = 0.0006) and p53 (p = 0.0024) expression rates were significantly increased in urachal carcinoma of the bladder cells compared to normal urothelium. IMP3 was elevated in Sheldon tumor stage IIIA compared to IIIB or greater (p = 0.0048). None of the analyzed protein markers was associated with survival. CONCLUSIONS: The independent prognostic value of a positive resection margin underlines the importance of complete surgical removal of urachal carcinoma of the bladder combined with en bloc resection of the median umbilical ligament and umbilicus. Our results in a limited number of samples show that Ki67, p53, RHAMM and IMP3 expression is enhanced but has no prognostic significance in urachal carcinoma of the bladder.