Grading of non-invasive papillary urothelial tumours- evaluation of the Royal College of Pathologists minimum dataset guidelines

Abstract

Objectives: The Royal College of Pathologists minimum dataset recommends the concurrent use of both WHO 1973 and 2004 grading systems for urothelial tumours. In this study, we determine whether the 1973 grades add prognostic value when using the 2004 system.

Methods: Non-invasive bladder tumours diagnosed in a single centre between 2005 and 2008 were reviewed. All had been initially graded using both 1973 and 2004 systems. Of 270 patients identified, 195 had a follow-up of >4 years and were included for analysis.

Results: The mean follow-up was 6 years (range 4-8.7). Recurrences were more frequent in patients with low grade papillary urothelial carcinoma (PUC) than PUNLMP (55v26% p=0.02) but there was no significant difference in grade or stage progression between these groups. Of 117 patients with low grade PUC, 36 were 1973 grade G1 and 81 G2. There was no significant difference in rate of recurrence (53v56%), grade progression (14v15%) or stage progression (0v5%) between G1 and G2 groups. Of 55 patients with high grade PUC, 18 were 1973 G2 and 37 G3. Recurrence was more frequent in patients with high grade G2 than G3 tumours (72v43% p=0.051) but there was no difference in stage progression (17v16% respectively).

Conclusions: The use of the 1973 grading system, in addition to WHO 2004, adds no clinical value. Our findings do not support the concurrent use of both systems.