Clinical Stage Migration and Survival for Renal Cell Carcinoma in the United States

Abstract

Background: The rising incidence of renal cell carcinoma (RCC) since the 1980s has been accompanied by stage migration toward early-stage (stage I) cancers. Stage migration drove an apparent increase in survival for RCC since the 1980s, but it is unclear whether it remains a contributor more recently.

Objective: To determine whether clinical stage migration has persisted and the relative impact of stage migration versus improvements in treatment on survival for RCC.

Design, setting, and participants: An epidemiologic assessment of stage migration and survival for 262 597 patients at diagnosis of RCC (2004-2015) across >1500 facilities in the National Cancer Database.

Outcome measurements and statistical analysis: Proportion of patients over time was assessed by clinical stage at diagnosis via Cochran-Armitage chi-square tests and linear regression. Mortality data were assessed with the Kaplan-Meier method for 5-yr overall survival, Cox proportional hazards regression, and propensity score matching to differentiate the impact of treatment including systemic therapy from stage migration.

Results and limitations: Greater diagnosis of clinical stage I disease (70%; p<0.001) was observed, with decreased diagnosis of stage III (8%; p<0.001) and stage IV (11%; p<0.001) up to 2007 followed by stabilization through 2015. Tumor size continues to decrease for localized tumors (mean-0.22cm stage I and-1.24cm stage II, 2004-2015). Histology demonstrated significant associations with stage. Five-year overall survival improved (67.9% [2004] to 72.3% [2010]) with gains in advanced RCC but not localized tumors. Models confirmed improved survival in recent years for stage IV patients. Systemic therapy was associated with improved survival (hazard ratio 0.811 [0.786-0.837], p<0.001). National Cancer Database limitations apply.

Conclusions: The proportion of patients presenting with stage I RCC has stabilized (70%), suggesting that stage migration may have ended. Localized tumors are detected with decreasing size, while advanced cancers have remained stable. Only 11% of patients now present with distant metastatic disease, but 5-yr overall survival is improving in recent years due to improved treatments rather than stage migration.

Patient summary: In this study, we found that stage migration toward early-stage cancers has ended for renal cell carcinoma (RCC). However, improved treatment for advanced RCC appears to be responsible for improved survival in recent years.

Keywords: Kidney cancer; Renal cell carcinoma; Small renal mass; Stage migration.