Continuous administration of EGFR-TKIs following radiotherapy after disease progression in bone lesions for non-small cell lung cancer

Background: There have been reports suggesting that continuous administration of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) is advantageous for patients in which disease progression was observed after the establishment of clinical benefit from EGFR-TKIs. We retrospectively evaluated the clinical course of patients who received continuous administration of EGFR-TKIs after disease progression was detected solely in bone lesions. Patients and Methods: The medical records of patients administered gefitinib or erlotinib between 2002 and 2010 were reviewed. We evaluated the progression-free survival (PFS) and overall survival (OS) in patients who had bone metastases after the establishment of clinical benefit from EGFR-TKI and who received radiation therapy for the bone lesion and continuous treatment with EGFR-TKI. Results: Ten patients were enrolled in this study. The median PFS and OS were 88 days and 330 days, respectively. Furthermore, a longer duration from the start of first EGFR-TKI to detection of bone metastases (p=0.0049) was identified as being significantly associated with a longer PFS. Conclusion: Our data suggest that continuous administration of EGFR-TKI is a treatment option for patients with bone metastases who previously benefited from therapy with EGFR-TKI.