Time Trends in Rates of XXXX Histologic Subtypes: True Incidence Changes or Evolving Diagnostic Practice?

@entity1 @entity71240 @entity2433 @entity4383 @entity978
BACKGROUND: Histologic subtypes of classical @entity978 [cHL; e.g., @entity4383 , mixed cellularity, @entity2433 ( @entity2433 )] are epidemiologically and prognostically distinctive. Therefore, unexplained, ongoing incidence rate declines for mixed cellularity and increases for @entity2433 require examination. METHODS: We analyzed detailed histology-specific @entity978 incidence rates in 1992 through 2011 U.S. SEER data (n = 21,372) and reviewed a regional subset of 2007 through 2011 @entity2433 pathology reports for insight into diagnostic practices. RESULTS: cHL rates were stable until 2007, then decreased for whites [annual percent change (APC) and 95% confidence interval (CI), -3.6% (-5.6% to -1.5%)]. @entity4383 rates declined after 2007 by 5.9% annually, with variation by gender, age, and race/ethnicity. In 1992 through 2011, mixed cellularity rates declined [ @entity71240 .0% (-4.7% to -3.3%)], whereas @entity2433 rates rose [5.3% (4.5%-6.2%)] overall and in most @entity1 groups. The 2007-2011 @entity2433 age-specific rates were more similar to mixed cellularity rates for 1992-1996 than 2007-2011. Trends in combined rates were minimal, supporting increasing misclassification of mixed cellularity, lymphocyte depletion, and specific @entity4383 subtypes as @entity2433 . Eighty-eight of 165 reviewed @entity2433 pathology reports addressed classification choice. Twenty (12.1%) justified the classification, 21 (12.7%) described insufficient biopsy material, and coders missed specific subtype information for 27 (16.4%). CONCLUSION: Recent @entity4383 rate declines largely represent true incidence changes. Long-term rate decreases for mixed cellularity and other less common subtypes, and increases for @entity2433 (comprising    30% of cHL cases in 2011), likely reflect changes in diagnostic and/or classification practice. IMPACT: Diminishing histologic subtyping undermines future surveillance and epidemiologic study of @entity978 . Guideline-based use of excisional biopsies and more coding quality control are warranted. Cancer Epidemiol Biomarkers Prev; 24(10); 1-15.   2015 AACR.
