'Conditional Survival' Relevant for Metastatic RCC Prognosis
With the advent of targeted therapy, median survival for patients with metastatic RCC has been extended over the past 7 years, necessitating more accurate prognostic measures. The investigators analyzed data on 1,673 patients with metastatic RCC treated with a first-line VEGF-targeted therapy between April 7, 2003, and October 12, 2010, from the International mRCC Database Consortium comprising institutions in Canada, the United States, Singapore, Denmark, and South Korea.
Primary outcome was 2-year conditional survival, “defined as the probability of surviving an additional 2 years from a given timepoint since the start of targeted therapy. Secondary analyses included 1-year and 3-year conditional survival, along with stratification of patients by Heng prognostic risk criteria and Karnofsky performance score, and conditional survival based on length of time on therapy,” they wrote.
For living patients, median follow-up was 20.1 months. The 2-year conditional survival probability increased from 44% (95% CI 41%—47%) at 0 months to 51% (46%—55%) at 18 months since beginning targeted therapy.
“When stratified by the Heng prognostic risk criteria defined at therapy initiation, 2-year conditional survival changed little in the favorable and intermediate groups, but in the poor-risk group, 2-year conditional survival improved from 11% (8%—15%) at 0 months to 33% (18%—48%) after 18 months,” they noted.
“When conditioned on time on targeted therapy from 0 months to 18 months, 2-year conditional survival improved from 44% (41%—47%) to 68% (60%—75%) in the overall population and from 74% (68%—79%) to 90% (77%—96%) in the favorable group, 49% (45%—53%) to 57% (45%—67%) in the intermediate group, and 11% (8%—15%) to 73% (43%—89%) in the poor-risk group,” they concluded.