Improvements in the prognosis of patients with stage IV renal cancer according to the era of therapeutic agents: an analysis of National Cancer Registry data.

Background: Advances in new drugs have been associated with improvements in the prognoses of individuals with stage IV renal carcinoma. We aimed to retrospectively evaluate the prognostic improvement of stage IV renal cancer over time using the Okayama Cancer Registry database, which is included in the National Cancer Registry (NCR) of Japan.

Methods: Patients identified in the database with stage IV renal cancer were included. Survival prognosis was analyzed by three periods according to significant advancements in novel therapeutic agents: early (up to March 2008), mid (April 2008-July 2016), and late (August 2016 onward). Overall survival (OS) was analyzed using the Kaplan-Meier methods and Cox proportional hazards models. Stratified Cox models were used to account for proportional hazards violations. Subgroup analyses included stratification by surgery status and disease extent (T4 vs. M1).

Results: In total, 1,182 patients were included in the study. The OS outcomes significantly improved across each period [early: reference; mid: hazard ratio (HR) =0.68, 95% confidence interval (CI): 0.59-0.78; late: HR =0.54, 95% CI: 0.41-0.69]. Subgroup analyses revealed that patients who had undergone initial surgery showed improved prognosis (early: reference; mid: HR =0.44, 95% CI: 0.29-0.69; late: HR =0.30, 95% CI: 0.16-0.56), whereas those receiving no initial surgery did not (early: no case available; mid: reference; late: HR =0.99, 95% CI: 0.64-1.53). Stratified Cox analysis identified age ≥70 years (HR =1.69, 95% CI: 1.47-1.95) and M1 disease (HR =2.95, 95% CI: 2.47-3.52) as independent predictors of worse survival. Significant improvement over time was observed among patients with T4 disease (early: reference; mid: HR =0.59, 95% CI: 0.42-0.82; late: HR =0.47, 95% CI: 0.27-0.81), patients, whereas no improvement was seen in those with M1 disease.

Conclusions: Prognosis of patients with stage IV renal cancer has improved over time, particularly among patients with locally advanced disease and those who undergo surgery. Therefore, therapeutic advances may have greater real-world impact on patients with resectable disease than on those with metastatic disease.