Survival Outcome Assessed According to Tumor Response and Shrinkage Pattern in Patients with EGFR Mutation–Positive Non–Small-Cell Lung Cancer Treated with Gefitinib or Erlotinib

• Published in: Journal of thoracic oncology Vol. 9; no. 2; pp. 200 - 204
• Main Authors: Takeda, Masayuki, Okamoto, Isamu, Nakagawa, Kazuhiko
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2014; Copyright by the European Lung Cancer Conference and the International Association for the Study of Lung Cancer; Lippincott Williams & Wilkins
• Subjects: Adenocarcinoma - drug therapy; Adenocarcinoma - genetics; Adenocarcinoma - mortality; Adult; Aged; Aged, 80 and over; Antineoplastic Agents - therapeutic use; Carcinoma, Non-Small-Cell Lung - drug therapy; Carcinoma, Non-Small-Cell Lung - genetics; Carcinoma, Non-Small-Cell Lung - mortality; Carcinoma, Squamous Cell - drug therapy; Carcinoma, Squamous Cell - genetics; Carcinoma, Squamous Cell - mortality; Epidermal growth factor receptor; Erlotinib Hydrochloride; Female; Follow-Up Studies; Genotype; Humans; Lung Neoplasms - drug therapy; Lung Neoplasms - genetics; Lung Neoplasms - mortality; Male; Middle Aged; Mutation; Mutation - genetics; Neoplasm Staging; Non–small cell lung cancer; Original; Polymerase Chain Reaction; Prognosis; Protein Kinase Inhibitors - therapeutic use; Quinazolines - therapeutic use; Receptor, Epidermal Growth Factor - genetics; Response; Survival; Survival Rate; Tumor shrinkage; Tyrosine kinase inhibitor; Response; Non–small cell lung cancer; Tyrosine kinase inhibitor; Tumor shrinkage; Mutation; Survival; Epidermal growth factor receptor
• ISSN: 1556-0864; 1556-1380; 1556-1380
• DOI: 10.1097/JTO.0000000000000053

Somatic mutations in the epidermal growth factor receptor gene (EGFR) are associated with a marked therapeutic response to EGFR–tyrosine kinase inhibitors (TKIs) in patients with advanced non–small cell lung cancer (NSCLC). Clinical indicators of the likely survival benefit of EGFR-TKI treatment in NSCLC patients with EGFR mutations have not been identified, however. We therefore evaluated progression-free survival (PFS) and overall survival (OS) according to tumor response and tumor shrinkage pattern in such patients. Among 145 EGFR mutation–positive NSCLC patients treated with EGFR-TKIs, 68 individuals were selected for analysis. Of the 68 selected patients, 6 achieved a complete response (CR), 42 a partial response (PR), and 14 stable disease (SD). Both PFS and OS were significantly longer in patients who achieved a CR or PR than in those who experienced SD. Multivariate analysis showed that a response (CR or PR) to EGFR-TKIs was significantly associated with both PFS and OS. Among the CR/PR group, the median maximal tumor shrinkage relative to baseline was 56%, and the median time to response (TTR) was 4.2 weeks. The subsets of these patients who experienced rapid tumor regression (TTR of ⩽4.2 weeks) or a high degree of tumor shrinkage (≥56%) did not show a more favorable PFS or OS compared with those who experienced slow tumor regression or a low degree of tumor shrinkage. Response (CR or PR) may represent the optimal surrogate for efficacy among EGFR mutation–positive NSCLC patients treated with EGFR-TKIs.