Recurrence and Progression Rates in Non-Invasive Papillary Urothelial Neoplasms of the Bladder: A Study of Tumors with Mixed Low and High Grades
Rashmi T Samdani, Shree G Sharma, Roni M Cox, Horace J Spencer, Neriman Gokden. University of Arkansas for Medical Sciences, Little Rock, AR
Background: The 2004 WHO/ISUP system categorizes non-invasive papillary urothelial neoplasms (PUN) into papilloma, papillary urothelial neoplasm of low malignant potential, papillary urothelial carcinoma low grade (LG) and high grade (HG). The tumors with mixed LG and HG areas do exist and WHO/ISUP system recommends that LG PUN cases that contain HG areas should be classified as HG. It is unclear from the existing literature whether the percentage of HG area affects the rates of recurrence and progression in mixed tumors.
Design: Retrospectively (2006-12) cases with an initial biopsy/transurethral resection diagnosis of non-invasive HG and LG PUN, and follow-up biopsies were reviewed. Forty-two cases met the criteria with an average follow up of 10.7 months (range:3-28 months). Three groups were created: 1- Pure LG; 2- LG with HG foci (2A:<10%, 2B:11-50%, 2C: >51%); 3- Pure HG. The criteria for diagnosing HG foci were: prominent architectural and cytological distortion at low power, increased N/C ratio, pleomorphism, and clumped chromatin. Recurrence was defined as occurrence on follow up of >3 months. Progression in stage and/or grade was studied. Cystoscopic findings were reviewed. Fisher's exact test utilized for statistical analysis.
Results: The average age was 67 years (44-79 yrs), M:F ratio was 3:1. The cases are summarized in Table 1. Four mixed LG/HG, 2 pure HG, and 1 pure LG case revealed stage progression from non-invasive to invasive carcinoma. The HG foci in mixed cases with stage progression ranged from 5 to 80%. Cystoscopically the LG/HG group had multifocal lesions at initial presentation and recurrences similar to those of pure HG cases.
|Group||No. of cases (n=42)||Recurrence n (%)||Grade Progression n (%)||Stage progression n (%)||Multifocality n (%) [1st bx]||Multifocality n (%) [Recurrence]|
|1||(p=0.87)||6 (60%)||0||1 (10%)||2 (20%)||1 (10%)|
|2||20||4 (20%)||12 (60%)||14 (70%)|
|2B||10||8 (80%)||2 (20%)||2||8||7|
|3||12||9 (75%)||0||2 (17%)||10 (83%)||12 (100%)|