Transthoracic Rebiopsy for Mutation Analysis in Lung Adenocarcinoma: Outcomes and Risk Factors for the Acquisition of Nondiagnostic Specimens in 199 Patients.

PURPOSE: To determine the outcomes of transthoracic rebiopsy for epidermal growth factor receptor (EGFR) mutation in patients with lung adenocarcinoma and to explore the clinical and procedure-related risk factors for the acquisition of nondiagnostic rebiopsy specimens.

PATIENTS AND METHODS: We retrospectively reviewed 367 patients with lung adenocarcinoma who underwent transthoracic core needle biopsy for mutation analysis from September 2011 to October 2016. Of these, 199 patients underwent rebiopsy. Patient characteristics, treatment history, target lesion characteristics, and procedure-related factors were evaluated. The adequacy rate of specimens for mutation analysis was evaluated. Univariable and multivariable analyses were performed to determine the independent predictors of nondiagnostic specimens.

RESULTS: Ninety percent of specimens (179 of 199) were adequate for mutation analysis. The EGFR mutation (exon 18-21) was 65% (117 of 179) and the EGFR T790M mutation 33% (59 of 179) of specimens. In univariable analysis, an internal low-attenuation area in the target lesion (P = .001) and pleural contact (P = .004) on computed tomography were significant risk factors for nondiagnostic specimens. In multivariable analysis, an internal low-attenuation area in the target lesion (odds ratio = 7.333; 95% confidence interval, 1.755-30.633; P = .006) was an independent predictor for acquisition of nondiagnostic specimens.

CONCLUSION: Image-guided transthoracic rebiopsy to obtain specimens for mutation analysis in lung adenocarcinoma provides high diagnostic accuracy, with a low rate of nondiagnostic specimens. The presence of internal low-attenuation area in the target lesion on computed tomography was an independent predictor for acquiring nondiagnostic specimens.