Cause-specific death after surgical resection for early-stage non-small-cell lung cancer

Abstract

Objectives: Surgical resection is the recommended treatment for patients with early-stage non-small-cell lung cancer. However, it is believed that causes other than lung cancer can lead to death following surgical resection. Investigating the risk factors for overall mortality and analysing the specific causes of death may indicate the degree of influence of other causes of death.

Methods: We assessed individual risk factors affecting overall and cause-specific mortality in a Cox proportional hazards model in a cohort of patients with resected Stage I/II non-small-cell lung cancer (n = 756) from 2007 to 2015 in a tertiary university centre. The follow-up period ranged from 3 days to 9.3 years. Median survival time was 7.3 years (95% confidence interval 6.0-7.9). A few patients died of cardiovascular disease (n = 19) and were included in the group 'other cause'. In a competing risk model, we evaluated the risk factors for specific causes of death in patients dying of lung cancer and dying of non-lung cancer specific conditions.

Results: The overall survival was 94%, 62% and 50% at 1, 5 and 7 years, respectively. At the end of the follow-up period, the risk of having died of, respectively, lung cancer or other causes was 36% and 24%. The cumulative incidence of death of lung cancer increased continuously during the study. Risk factors predicting death of all causes and death of non-small-cell lung cancer were increasing age, severely reduced lung function, Eastern Cooperative Oncology Group Performance Status ≥2, preoperative examination without positron emission tomography/computed tomography, histological tumour diagnosis other than adenocarcinoma and squamous cell carcinoma and increasing disease stage. In patients dying of other causes, age, gender, body mass index, smoking and Eastern Cooperative Oncology Group Performance Status ≥2 affected the mortality rate.

Conclusions: The probability of having died of lung cancer continued to increase beyond 5 years after the operation. Surveillance of risk factors associated with an increased mortality rate should be considered in the postoperative follow-up examination after lung cancer resection.

Keywords: Cause-specific mortality; Competing risk; Lung cancer; Mortality; NSCLC; Survival; Thoracic oncology; Thoracic surgery.