Advanced adenocarcinoma of the lung: comparison of CT characteristics of patients with anaplastic lymphoma kinase gene rearrangement and those with epidermal growth factor receptor mutation.

PURPOSE: To study the differences in computed tomographic (CT) characteristics between patients with advanced lung adenocarcinoma who have anaplastic lymphoma kinase (ALK) gene rearrangement and those who have epidermal growth factor receptor (EGFR) mutations.

MATERIALS AND METHODS: This retrospective study was approved by the institutional review board. Informed consent was waived. Patients with stage IV adenocarcinoma (n = 198) were enrolled from November 2004 to December 2013, including 68 patients with ALK rearrangement and 130 with EGFR mutation. Two independent radiologists evaluated the main tumor in each patient and determined its size, type, margins, lymph node metastasis, and intrathoracic metastasis (lung, pleural or pericardial, or bone). A multiple logistic regression model was applied to discriminate clinical and CT characteristics between the types of mutation.

RESULTS: The κ index for assessment of tumor and node stage between radiologists was 0.8530 to 0.9388. Most of the main tumors in patients with both types of mutation appeared as solid masses. In univariate analysis, patients with an ALK rearrangement were younger (P < .001) and were more likely to be men (P = .001), to have never smoked (P = .002), and to have pleural or pericardial metastases (P < .05) compared with those with EGFR mutations. In multivariate analysis, lobulated margins (odds ratio, 4.815; 95% confidence interval [CI]: 1.789, 12.961; P = .002), N2 or N3 lymph node involvement (odds ratio, 2.445; 95% CI: 1.005, 5.950; P = .049), and lymphangitic lung metastasis (odds ratio, 8.485; 95% CI: 2.238, 32.170; P = .002) were more common in patients with ALK rearrangement than in those with EGFR mutation. The area under the receiver operating characteristic curve was 0.855.

CONCLUSION: Adenocarcinomas with ALK rearrangement appeared as solid masses with lobulated margins at CT and were more likely to be associated with lymphangitic metastasis, advanced lymph node metastasis, and pleural or pericardial metastasis than were tumors with EGFR mutations.