Validation of a molecular and pathological model for five-year mortality risk in patients with early stage lung adenocarcinoma

Introduction:

The aim of this study was to validate a molecular expression signature [cell cycle progression (CCP) score] that identifies patients with a higher risk of cancer-related death after surgical resection of early stage (I-II) lung adenocarcinoma in a large patient cohort and evaluate the effectiveness of combining CCP score and pathological stage for predicting lung cancer mortality.

Methods:

Formalin-fixed paraffin-embedded surgical tumor samples from 650 patients diagnosed with stage I and II adenocarcinoma who underwent definitive surgical treatment without adjuvant chemotherapy were analyzed for 31 proliferation genes by quantitative real-time polymerase chain reaction. The prognostic discrimination of the expression score was assessed by Cox proportional hazards analysis using 5-year lung cancer-specific death as primary outcome.

Results:

The CCP score was a significant predictor of lung cancer-specific mortality above clinical covariates [hazard ratio (HR) = 1.46 per interquartile range (95% confidence interval = 1.12–1.90; p = 0.0050)]. The prognostic score, a combination of CCP score and pathological stage, was a more significant indicator of lung cancer mortality risk than pathological stage in the full cohort (HR = 2.01; p = 2.8 × 10⁻¹¹) and in stage I patients (HR = 1.67; p = 0.00027). Using the 85th percentile of the prognostic score as a threshold, there was a significant difference in lung cancer survival between low-risk and high-risk patient groups (p = 3.8 × 10⁻⁷).

Conclusions:

This study validates the CCP score and the prognostic score as independent predictors of lung cancer death in patients with early stage lung adenocarcinoma treated with surgery alone. Patients with resected stage I lung adenocarcinoma and a high prognostic score may be candidates for adjuvant therapy to reduce cancer-related mortality.

Epidemiology of Lung Cancer in Spain and Forecast for the Future

Lung cancer, a steadily growing problem, ranks as the first cause of tumor-related deaths in developed countries. The relation between lung cancer and smoking makes it a potentially avoidable disease. Found mainly in men, it has made alarming gains among women. The main prognostic factor is the possibility of receiving curative surgery; however, in real practice the diagnosis usually comes when the disease has reached an advanced stage, when only 20% can be treated surgically. Nonsurgical treatments based on chemo- and radiotherapy have not advanced appreciably in recent years, and 5-year survival is poor, estimated at only around 7% to 12% in Spain. Attempts must be made to improve preventive measures and early diagnosis in order to improve the prognosis for lung cancer patients.