The incidence and prognostic significance of bone metastases and skeletal-related events in lung cancer patients: A population-based cohort study in Denmark.

Abstract

e18074 Background: Lung cancer often presents at an advanced stage of disease and can give rise to bone metastases (BM). Metastatic bone disease is associated with painful and debilitating complications, but less is known about its effects on patient survival, particularly after the occurrence of skeletal-related events (SREs). Methods: Using data from the Danish Cancer Registry, we studied 11,940 patients diagnosed with lung cancer (1999-2003) with follow-up through December 31, 2008. We estimated the cumulative incidence of BM following cancer diagnosis and the subsequent occurrence of SREs (fractures, spinal cord compression, and surgery to the bone), treating death as a competing risk. We computed and compared survival for three lung cancer subgroups – no BM, BM but no SREs, and BM with SREs – using Kaplan-Meier and multivariate Cox models. Results: Overall, 6.4% (n = 760) were diagnosed with BM either at lung cancer diagnosis or during follow-up: 5.1% (n = 607) had BM but no SRE and 1.3% (n = 153) had both BM and at least one SRE (spinal cord compression was most frequent). Although the cumulative incidence of BM and the subsequent occurrence of SREs were similar according to histologic type, the incidence of BM appeared slightly elevated in those with adenocarcinomas (5-year cumulative incidence of 8.5% (95% confidence interval [CI]: 7.7-9.3) in adenocarcinoma versus 6.3% (95% CI: 5.9- 6.8) for all lung cancer patients combined). Less than 1% of lung cancer patients diagnosed with bone metastases survived beyond three years. One-year crude survival was lowest for those with both BM and SREs (4.4%) compared to the groups with no BM (35.3%) and with BM but no SREs (5.2%). Accordingly, the adjusted mortality rate was 2.1 times greater in those with BM alone (95% CI: 1.9-2.3) and 2.7 times higher for those with both BM and SREs (95% CI: 2.3-3.1) compared with lung cancer patients without BM and SREs. Conclusions: Survival was poorer for lung cancer patients with BM versus those without, but short-term mortality rates appear even higher among those with BM who also experience an SRE. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Amgen Amgen Amgen