Conditional cancer-specific versus cardiovascular-specific survival after lobectomy for stage i non-small cell lung cancer

Background: Conditional cancer-specific survival rates account for changes in the risk of death from cancer over time. There may be a point during follow-up when patients who undergo lobectomy for stage I non-small cell lung cancer (NSCLC) are as likely to die of cardiovascular disease as of cancer. Methods: Using the Surveillance Epidemiology and End Results Database (1988 through 2005), we identified patients 50 years old and older who underwent lobectomy for stage I NSCLC. We used competing risks methods to calculate conditional survival rates and to ascertain if there is a point in follow-up where the risk of dying of cancer is equivalent to the risk of dying of cardiovascular disease. Results: In all, 22,518 patients met our inclusion criteria. The difference in the 5-year conditional probability of dying of cancer and the 5-year conditional probability of dying of cardiovascular disease decreased with time; in the whole cohort, these probabilities were equivalent if patients survived to 7 years after lobectomy (p = 0.11). With increasing age, the probability of dying of cancer and the probability of dying of cardiovascular disease became equivalent at earlier time points. Furthermore, the 5-year probability of dying of cardiovascular disease was significantly greater than the 5-year probability of dying of cancer for patients aged 70 to 79 years who survived to 7 years and for patients aged 80 years and older who survived to 5 years after lobectomy. Conclusions: For patients undergoing lobectomy for stage I NSCLC, cardiovascular-specific mortality becomes increasingly important over the course of follow-up, especially among elderly patients.