Mutation in the epidermal growth factor receptor (EGFR) gene is not a prognostic factor in persons with non-small cell lung cancer (NSCLC) who have undergone surgical resection or who have received conventional therapies to fight a recurrence, researchers have discovered. However, after disease recurrence, the treatment with EGFR tyrosine kinase inhibitors (TKIs) may prolong survival.
As the investigators noted in Journal of Thoracic Oncology (2013;8:171-178), the presence of mutation in the EGFR gene is known as a predictive marker for the response to EGFR TKI treatment. Whether these EGFR mutations are prognostic factors for NSCLC is debatable, however.
To explore this issue, the research team analyzed survival among persons with NSCLC whose EGFR mutation status had been tested. The pathologic cell types of the men and women whose samples were studied were squamous cell carcinoma in 227 patients and adenocarcinoma in 636 patients.
EGFR mutations were detected in 354 persons, and were frequently observed in adenocarcinoma in younger, early-stage, female never-smokers. Bronchioloalveolar carcinoma pattern and the presence of EGFR mutation showed better long-term survival in univariate analysis of this subset of patients. But EGFR mutation did not remain a significant prognostic factor in multivariate analysis; only age, pathologic stage, and smoking status did.
Pathologic stage was the only independent prognostic factor in recurrence. After recurrence, smoking status was the only significant risk factor that affected survival. However, patients with EGFR mutation who used EGFR TKIs survived longer than did patients who received conventional chemotherapy.
“The clinical observation that patients with EGFR mutation seem to survive longer may be because EGFR mutation is more frequently associated with other significant prognostic factors, such as age, stage, or smoking status,” wrote the authors. “On the basis of our results, the pathologic stage seems to affect the prognosis by influencing the cancer recurrence, and smoking status seems to be the most important prognostic factor for overall survival.”