Background: Patients with non-small-cell lung cancer (NSCLC) with anaplastic lymphoma kinase (ALK) rearrangement mutation are found to be 3-13%.
Aim: To evaluate the prevalence of ALK mutations in EGFR-negative NSCLC patients in Bulgaria.
Materials and methods: One hundred and thirty-two patients with EGFR-negative NSCLC were examined for ALK mutation analysis between January and June 2016. Data were obtained from patients' register of four major oncological hospitals in Bulgaria.
Results: Data were available for 124 (93.9%) patients, tumor mass was insufficient for analysis in 8 (6.1%) patients. Most of the patients were with adenocarcinoma (82 patients, 62.1%); 11 patients (8.3%) were with squamous histology and 2 patients (1.5%) were with other type of NSCLC. Histology data were missing in 37 patients (28.0%). ALK mutation was confirmed in 5 patients (3.8%), 119 (90.2%) patients had ALK wild type. ALK positive patients were with adenocarcinoma (n=3), squamous cell carcinoma (n=1) and other type (n=1) NSCLC. All ALK mutations were observed in never smokers (n=3) and former smokers (n=2).
Conclusion: The present study is the first of this kind in Bulgaria - it investigates the prevalence of ALK mutation rate in EGFR-negative NSCLC patients, which was found to be 3.8%. The presence of EGFR, ALK or other driver mutations is a prerequisite for targeted therapy and thus needs to be accurately assessed in NSCLC.
Keywords: ALK mutation; Bulgaria; NSCLC; non-small-cell lung cancer; prevalence.