Trends in reporting histological subtyping of renal cell carcinoma: association with cancer center type

Histological classification of renal cell carcinoma (RCC) has become increasingly important for clinical management. We identified 295 483 RCC diagnosed from 1998-2014 in the National Cancer Database (NCDB) to examine temporal trends in proportions of RCC with unspecified histology and several specific histologies from the 1998 and 2004 World Health Organization classifications of RCC. Further, multivariable log binomial analysis of 101 062 RCC diagnosed from 2010 to 2014 was used to determine whether the association of diagnosing/treating facility type and the proportion of unspecified RCC is independent of patient demographic and clinical factors. Between 1998 and 2014, the proportion of histologically unspecified RCC decreased substantially in all facility types, with the decrease smallest in community programs (from 86.0% to 28.1%) and largest in National Cancer Institute-designated centers (from 85.1% to 9.8%). These decreases were offset by increases in percentages of papillary, clear cell, and chromophobe RCC cases. During 2010 to 2014, relative to community programs, RCCs were 21% less likely to be reported as unspecified histology (adjusted prevalence ratio [aPR] = 0.79; 95% CI, 0.68-0.92) in comprehensive community programs, 32% less likely in integrated network programs (aPR = 0.68; 95% CI, 0.57-0.92) and academic programs (aPR = 0.68; 95% CI, 0.54-0.87), and 63% less likely (aPR = 0.37; 95% CI, 0.26-0.52) in National Cancer Institute -designated programs. These results have implications for the optimal selection of targeted systemic therapies for patients with advanced disease, and for the potential value of cancer registry data in pathology quality improvement programs to promote more rapid and consistent adoption of new classifications of RCC and other neoplasms.