Purpose: Conditional survival (CS) is an accurate estimate of survival probability for patients who have already survived at least 1 year after diagnosis. The purpose of this study was to determine whether ethnicity plays a role in 5-year CS rates for patients with non-small cell lung cancer (NSCLC).
Materials and methods: Using the Surveillance, Epidemiology, and End Results database, we analyzed 96,480 patients with NSCLC diagnosed between 1988 and 1995. Patients were divided into five ethnic groups: White (non-Hispanic), Hispanic, African American, Asian/Pacific Islander, and Native American/Alaskan. Using the life table method, we computed observed 5-year CS rates for patients who had already survived up to 5 years after diagnosis. Results were analyzed by stage, age, sex, and histology.
Results: In general, 5-year CS rates increase for all ethnicities as time from diagnosis increases, but African Americans continued to have lower CS rates compared with other ethnic groups, even up to 5 years from diagnosis. When analyzed by stage, Hispanics with stage IV disease showed the greatest improvement in CS rate, increasing to 73% at 5 years from diagnosis. Among patients older than 70 years, African Americans had the lowest CS at 5 years--only 28%, compared with 40% to 47% for other groups. When analyzed by histology, Hispanics with large cell carcinoma had the worst CS rate (35% at 5 years).
Conclusion: For patients with NSCLC surviving a period of time after diagnosis, 5-year CS rates vary by ethnicity. CS can provide accurate prognostic information for patients with NSCLC who have already survived several years after diagnosis.