The combination of the blood based tumor biomarkers cytokeratin 19 fragments (CYFRA 21-1) and carcinoembryonic antigen (CEA) as a potential predictor of benefit from adjuvant chemotherapy in early stage squamous cell carcinoma of the lung (SCC)

Objectives To determine whether the tumor biomarkers cytokeratin 19 fragment (CYFRA 21-1) and carcinoembryonic antigen (CEA), which are prognostic in early-stage non-small cell lung cancer (NSCLC), can predict which patients benefit from adjuvant chemotherapy (CTx). Materials and methods Serum samples were collected preoperatively from patients with NSCLC who underwent resection. Samples were retrospectively analyzed for CYFRA 21-1 and CEA via electrochemiluminescence immunoassay. Recurrence-free survival (RFS) was compared for patients who received adjuvant CTx versus surgery alone, stratified based on the following prognostic classifications: (1) tumor stage (pT1‐2/N0 [stage I] or pT3/N0 or pT1‐2/N1 [stage II]), (2) biomarker-based risk score, (3) clinical characteristics. Absolute 2-year RFS rates were calculated via Kaplan-Meier estimations; statistical significance level: 0.05. Results 227 patients were included (stage I: 69%; male: 67%; median age 65 years); 70 received adjuvant CTx. Median duration of sample collection was 58.8 months. All high-risk patients (by all three prognostic classifications) who received adjuvant CTx had a longer RFS versus those who received surgery alone. In patients with squamous cell carcinoma (SCC) classified as high risk by all three prognostic classifications, there was a benefit from adjuvant CTx versus surgery alone (tumor stage hazard ratio [HR] 4.9, p = 0.004; biomarker levels HR 9.4, p = 0.002; clinical characteristics HR 9.0, p = 0.003). None of the prognostic classifications were able to predict a benefit from adjuvant CTx in patients with adenocarcinoma. Conclusion Baseline CYFRA 21-1 and CEA levels may provide further information to help clinicians decide which patients with SCC should receive adjuvant CTx. Further evaluation of these biomarkers is warranted.