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

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.