Epidermal Growth Factor Receptor Mutations Effect on Volume Doubling Time of Non-Small-Cell Lung Cancer Patients

Background: The purpose of this study was to retrospectively compare the volume doubling time (VDT) on serial computed tomography (CT) of non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutation with that of NSCLC without the mutation. Methods: One hundred and two pathologically proven NSCLCs, including 69 patients with lung adenocarcinoma, were reviewed with helical CT. Each tumor underwent at least two CT scans. The VDT was calculated using a modified Schwartz formula. EGFR mutations at exons 18-21 were determined by common fragment analysis and Cycleave method. Result: The median VDT of all the patients was 188 days. EGFR mutations were noted in 35 of the 102 patients. The VDT in the 35 patients with EGFR mutations (median 676 days) was longer than that in the 67 patients without EGFR mutations (median 139 days) (p < 0.001). By histology subtype, the VDT of adenocarcinoma (305 days) was longer than that of squamous cell carcinoma (81 days) and other types (90 days; p < 0.001). Conclusion: In NSCLC patients, positive EGFR mutation status may be associated with longer VDT, which seemed to have a slowly progressive and less-aggressive character. More accurate evaluation of VDT may be helpful for understanding the natural history of EGFR mutation-positive NSCLC and treatment with EGFR tyrosine kinase inhibitors.