Variation in causes of death in patients with non-small cell lung cancer according to stage and time since diagnosis

Abstract

Background: Many patients with non-small cell lung cancer (NSCLC) die within the first few years of diagnosis, and considerable excess mortality remains even after 5 years. We investigated the death rate and the distribution of causes of death for NSCLC patients by age and stage at diagnosis during long-term follow-up.

Patients and methods: All 72 021 patients aged 45-89 years diagnosed with stage I-III NSCLC between 1989 and 2008 in the Netherlands and who died up till 2011 were derived from the Netherlands Cancer Registry and linked with the database of Statistics Netherlands for underlying causes of death. Mortality ratios and proportional distribution of causes of death were calculated during 5 time periods after diagnosis of NSCLC (up to 15 years).

Results: Median follow-up was 9.6 years (range: 0-23 years). Lung cancer was the predominant cause of death in the first 6 years after diagnosis (being 80%-85% and ∼90% up to 3 years for localized and locally advanced disease, respectively, and ∼60%-75% and ∼75%-85% during years 4-6 for both stage groups, respectively). Thereafter, lung cancer as cause of death proportionally decreased with time since diagnosis, but remained over 30%. Hence, cardiovascular diseases and chronic obstructive pulmonary diseases (COPD) became more important causes of death, especially for patients aged >60 years at diagnosis (up to 34% for cardiovascular diseases and up to 19% for COPD).

Conclusions: With time, the relative contribution of cardiovascular and COPD causes of death increased, although the absolute contribution of lung cancer remained high in non-metastatic NSCLC. Therefore, managing morbidity of these diseases remains relevant.

Keywords: causes of death; conditional survival; excess mortality; long-term; non-small cell lung cancer.