Transitional cell carcinoma is a common tumour, with over 10 000 cases diagnosed each year and almost 5000 deaths. Traditional prognostic factors are grade, stage, size, multiple tumours, bladder neck involvement and age, and the tumour, node, metastasis criteria¹ for staging are widely accepted. Tumours invading the subepithelial connective tissue are classified as pT1. Publications have looked at the depth of infiltration of transitional cell carcinoma with infiltration of the lamina propria for about 10 years.^2–7 The publication of Scottish Intercollegiate Guidelines Network (SIGN) guideline 85 “Management of Transitional Cell Carcinoma of the Bladder”⁸ cites two references as evidence of microstaging being an independent prognostic variable. However, there was concern after the publication of this guidance that there would be significant training requirements for histopathologists and concerns regarding the consistency of interpretation. Furthermore, published literature includes different staging systems for pT1 transitional cell carcinoma including a two-stage and a three-stage system. The three-stage system is variably defined; although all systems show prognostic information, one three-stage system was adopted here as it was believed to be the most straightforward (table 1).

It was thought important to test the consistency of microstaging of transitional cell carcinoma by general pathologists before the roll-out of microstaging by the West of Scotland Urology Cancer Network. The aim of this study was therefore to determine whether general pathologists were able to reproducibly microstage pT1 transitional cell carcinoma of the bladder and whether the two-stage or three-stage system was more consistent (table 1). Another aim of the study was to see whether pathologists were reliably able to recognise muscularis mucosae and whether this affected the microstaging.

Methods

Using records from the weekly urology multidisciplinary team meetings for NHS Ayrshire and Arran, a …