Impact of smoking amount on clinicopathological features and survival in non-small cell lung cancer

Abstract

Background: Screening for early detection of lung cancer has been performed in high-risk individuals with smoking history. However, researches on the distribution, clinical characteristics, and prognosis of these high-risk individuals in an actual cohort are lacking. Thus, the objective of this study was to retrospectively review characteristics and prognosis of patients with smoking history in an actual lung cancer cohort.

Methods: The present study used the lung cancer cohort of the Catholic Medical Centers at the Catholic University of Korea from 2014 to 2017. Patients with non-small cell lung cancer were enrolled. They were categorized into high and low-risk groups based on their smoking history using the national lung screening trial guideline. Distribution, clinical characteristics, and survival data of each group were estimated.

Results: Of 439 patients, 223 (50.8%) patients were in the high-risk group. Patients in the high-risk group had unfavorable clinical characteristics and tumor biologic features. Overall survival of the high-risk group was significantly shorter than that of the low-risk group with both early (I, II) and advanced stages (III, IV). In multivariate analysis, heavy smoking remained one of the most important poor clinical prognostic factors in patients with lung cancer. It showed a dose-dependent relationship with patients' survival.

Conclusions: High-risk individuals had poor clinical outcomes. Patients' prognosis seemed to be deteriorated as smoking amount increased. Therefore, active screening and clinical attention are needed for high-risk individuals.

Keywords: Cigarette smoking; Non-small cell lung cancer; Screening.

Fig. 1

Study flow diagram

Fig. 2

Kaplan-Meier estimate of overall survival of subjects stratified by risk and stage Panel a shows the difference of overall survival for patients with high and low risk and Panel b, c, d show the difference of overall survival for patients with high and low risk group according to cancer stage. Panel e shows the difference of overall survival according to MILD trial eligible criteria

Fig. 3

Cox Proportional hazards model for overall survival

Fig. 4

The optimal cutoff points to distinguish patients’ survival on time-dependent ROC curve. Panel a and b shows the ROC curve for 1 and 3-year mortality, respectively. Panel c shows the time-dependent AUC and corresponding cutoff points through the whole study period

Fig. 5

Kaplan-Meier estimate of overall survival of subjects stratified by amount of lifetime cigarette smoking