A Cell Type Independent Binary Grading System Does Not Significantly Improve Endometrial Biopsy Interpretation

Area of Science:

• Gynecologic Oncology
• Pathology
• Cancer Grading Systems

Background:

• The International Federation of Gynecology and Obstetrics (FIGO) grading system, combined with World Health Organization (WHO) diagnostic criteria for tumor cell type, is the standard for endometrial carcinoma biopsy evaluation.
• Discrepancies between biopsy and hysterectomy diagnoses are noted, prompting research into alternative grading methods.
• A recently proposed cell type independent (CTI) binary grading system aims for low-risk and high-risk assessment without relying on cell type determination.

Purpose of the Study:

• To assess the utility and accuracy of the novel cell type independent (CTI) grading system for endometrial carcinoma on biopsy.
• To compare the CTI grading system's performance against the established World Health Organization/International Federation of Gynecology and Obstetrics (WHO/FIGO) grading system in biopsy specimens.
• To evaluate interobserver agreement and ease of use for both grading systems in biopsy evaluation.

Main Methods:

• Archived endometrial biopsy specimens from 70 cases of endometrial carcinoma were retrospectively reviewed.
• Three independent observers graded the biopsies using both the WHO/FIGO system (including tumor cell type determination) and the CTI grading system.
• Overall accuracy, interobserver agreement (using kappa statistics), and perceived ease of use were analyzed and compared between the two systems.

Main Results:

• Both the WHO/FIGO and CTI grading systems demonstrated comparable substantial accuracy, with kappa values of 0.71 and 0.69, respectively.
• Similar rates of overgrading low-risk tumors were observed: 20.9% for WHO/FIGO versus 25.6% for CTI.
• The CTI grading system did not show superiority over the WHO/FIGO system in terms of accuracy for subtyping, grading, or interobserver reproducibility.

Conclusions:

• The cell type independent (CTI) grading system does not offer significant advantages over the current WHO/FIGO grading system for evaluating endometrial carcinoma on biopsy.
• Despite challenges in determining cell type, the proposed CTI system did not improve diagnostic accuracy or reproducibility in this biopsy grading context.
• The established WHO/FIGO system remains a reliable standard for endometrial carcinoma biopsy grading, with the CTI system showing no clear benefit for this application.