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Ashish Kamat: Hybrid 3-Tier Bladder Cancer Grade – The Mutually Beneficial Marriage of 2 Grading Systems

Ashish M. Kamat/euoncology.europeanurology.com

Apr 6, 2025, 15:27

Ashish Kamat: Hybrid 3-Tier Bladder Cancer Grade – The Mutually Beneficial Marriage of 2 Grading Systems

Ashish Kamat, Endowed Professor of Urologic Oncology (Surgery) and Cancer Research at University of Texas MD Anderson Cancer Center, shared his recent article on X:

“Hybrid 3-Tier Bladder Cancer Grade: The Mutually Beneficial Marriage Of Two Grading Systems

The hybrid 3-tier system, blends the best of WHO 1973 and WHO 2004/2022 classifications for non-muscle-invasive (Ta, T1) cases – why do we need this?

Back in 2004, WHO aimed to replace the 1973 three-tier system (Grade 1, 2, 3) with a simpler LG/HG split. But pathologists kept using both, reporting them side-by-side per EAU guidelines. Neither system was perfect WHO 2004’s high-grade group is too broad (50% of patients), and WHO 1973’s Grade 2 is a gray zone.

Enter the hybrid system, proposed by The USCAP, International Society of Urological Pathology (ISUP)

Here’s the breakdown of the hybrid 3-tier system:

Low: Maps to WHO 2004 Low + WHO 1973 Grades 1 and 2 (less aggressive).

High-grade 2 (favorable): WHO 2004 High + WHO 1973 Grade 2 (intermediate risk).

High-grade 3 (unfavorable): WHO 2004 High + WHO 1973 Grade 3 (highest risk).

The hybrid 3-tier system is gaining traction fast. The European Association of Urology (EAU) guideline panel on NMIBC now recommends it as an alternative to reporting both WHO 1973 and 2004/2022 grades. The Royal College of Pathologists has added it to their bladder cancer dataset too.

A European Urology study with experts across Europe and beyond calls it a “mutually beneficial marriage” of the two systems. Is this the global standard we’ve been waiting for?”

Hybrid 3-Tier Bladder Cancer Grade: The Mutually Beneficial Marriage Of Two Grading Systems

Authors: Ashish Kamat, Bas W.G. van Rhijn, and Theodorus Van der Kwast

Ashish Kamat