Prediction of distant recurrence in resected stage I and II lung adenocarcinoma

Optimal procedures for adjuvant treatment and post-surgical surveillance of resected non-small-cell lung cancer remain under discussion. Pathological features are the main determinant of follow-up therapy but have limited ability to identify patients at risk of recurrence. Increasingly, molecular markers are incorporated into clinical decision-making, including measures of tumor growth. The CCP score is a quantitative, molecular measure of proliferation derived from the RNA expression of 31 cell cycle genes and a component of the molecular prognostic score (mPS). The mPS score is a linear combination of CCP score and pathological stage. CCP score and mPS are independent predictors of survival in resected lung adenocarcinoma.

CCP scores were determined by RT-qPCR for 318 patients diagnosed with stage I-II lung adenocarcinoma. Association of mPS and CCP score with distant recurrence and lung-cancer specific survival was assessed in Cox proportional hazards regression models adjusted for age, gender, tumor size, pathological stage and pleural invasion. Distant recurrence-free survival and lung-cancer specific survival by mPS risk group were calculated by Kaplan-Meier survival analysis.

CCP scores were obtained for 205 stage I and 84 stage II patients. CCP score and mPS were independent markers of distant recurrence (CCP: HR 1.62, 95%CI 1.15-2.29, p=0.0055; mPS: HR 2.22, 95%CI 1.11-4.44, p=0.023). Patients with low mPS tumors were at significantly reduced risk of distant recurrence (log-rank p=4.2×10^-5). Among stage I patients, stratification by mPS identified a patient group with increased risk of distant recurrence (36%, 95%CI 28-46%, log-rank p=0.0011) CONCLUSIONS: The molecular prognostic score stratifies early-stage, resected lung cancer patients for risk of distant recurrence and could be useful to inform treatment and surveillance decisions.