Effect of stage and grade migration on cancer specific mortality in renal cell carcinoma patients, according to clear cell vs. non-clear cell histology: A contemporary population-based analysis.
Academic Article
Overview
abstract
OBJECTIVES: To test the effect of stage and grade migration on cancer specific mortality (CSM) in renal cell carcinoma (RCC) patients, according to clear cell (ccRCC) vs. non-ccRCC histology. METHODS AND MATERIALS: Within the Surveillance, Epidemiology, and End Results registry (2004-2015), we identified patients with ccRCC and non-ccRCC (papillary [papRCC], chromophobe [chRCC], sarcomatoid [sarcRCC], and collecting duct [cdRCC]). Two consecutive time groups were considered - historical (2004-2009) and contemporary era (2010-2015). Temporal trends of tumor characteristics were evaluated. Cumulative incidence plots and multivariable competing risks regression models tested the effect of year groups on CSM. RESULTS: Overall, 24,746 and 73,228 patients with non-ccRCC and ccRCC were evaluated. Of those, 42% and 58% were recorded in historical and contemporary era. Time trend analyses showed (1) tumor size decreased for non-ccRCC (estimated annual percent changes [EAPC]: -1.1%; P <0.01) and for ccRCC (EAPC: -1.0%; P <0.01), (2) rates of G3/G4 decreased for non-ccRCC (EAPC: -0.7%; P = 0.03), but increased for ccRCC (EAPC: +1.1; P <0.01), 3) rates of node positive disease decreased for non-ccRCC (EAPC:-3.1%; P = 0.02), but were stable for ccRCC (EAPC: +0.4; P =0.5), (4) rates of metastatic disease at diagnosis decreased for non-ccRCC (EAPC: -3.2%; P <0.01), but were stable for ccRCC (EAPC: -0.6%; P = 0.1), (5) among non-ccRCC, the percentage of papRCC increased (EAPC:+1%; P <0.01), while the percentage of sarcRCC (EAPC: -7%; P <0.01) and cdRCC (EAPC: -11.2%; P <0.01) decreased. Finally, in multivariable CRR models, lower CSM was recorded for contemporary non-ccRCC (HR: 0.7; P <0.001) and ccRCC (HR: 0.8; P <0.001) patients. CONCLUSION: Our findings illustrate a favorable stage and grade migration and improved cancer-specific mortality in contemporary non-ccRCC. Additionally, despite absence of meaningful stage migration in ccRCC, improved cancer-specific mortality in contemporary patients was also recorded. In consequence, a 2-tiered process appears to be operational in non-ccRCC vs. a 1-tiered phenomenon in ccRCC.
