International Feasibility of Applying Diagnostic Essential Criteria of the Fifth Edition World Health Organization Classification of Female Genital Tumors: Evidence for a Global Gap in Health Care Equity

The new categories of diagnostic essential criteria and desirable criteria in the fifth edition World Health Organization Classification of Female Genital Tumors (fifth WHO FGT) aim to standardize the classification of gynecologic tumors worldwide. As some essential criteria require biomarkers (immunohistochemistry [IHC] or molecular tests), we hypothesized that the applicability of the fifth WHO FGT criteria may be limited by access to these tests due to local resource constraints. After defining the essential biomarkers in the fifth WHO FGT, we conducted an international survey of pathologists to determine accessibility to essential biomarkers and then evaluated access as a function of the pathologist's country income category. A total of 37 IHC and 6 molecular tests are considered essential for diagnosing a spectrum of common and less common tumors. Among 480 respondents from 76 countries, access to the printed or online version of the fifth WHO FGT was associated with country income (P < .0001); 62.5% of low-income country respondents reported no access to either version. Routine access to IHC in general and routine access to each of the essential IHC were significantly associated with the country income category (P < .0001). Only 12.5% of low-income country respondents reported routine access to IHC in general, and none reported routine access to any essential molecular tests. Short tandem repeat genotype testing for molar pregnancy diagnosis was the least accessible essential molecular test worldwide, available to only 26.6% of the respondents, most of whom were in high-income countries. Additional essential criteria for some tumors consisted of one of 18 different specific types of tumor differentiation for which no morphologic definition was provided; high-income country respondents were more likely to routinely use IHC in these settings than lower-income country respondents (P < .0001). Conversely, the patient bore the direct responsibility for paying for IHC when used in lower-income countries compared with high-income countries (P < .0001). This survey demonstrates a global gap in health care equity due, in part, to limited access to biomarkers deemed as essential for diagnosis by the fifth WHO FGT and to the lack of diagnostic criteria adaptable to resource-limited environments. Based on the survey results, we offer several practical strategies for narrowing this gap in future editions of the WHO FGT, chief among them being a move toward resource-stratified diagnostic criteria.