Role of Imaging Biomarkers in Predicting Anaplastic Lymphoma Kinase–Positive Lung Adenocarcinoma

Abstract

Objectives 

For the ultimately efficient screening of anaplastic lymphoma kinase gene (ALK)–positive cases, combination of radiometabolic characteristics with clinicopathologic features may be more useful. Therefore, we determined radiologic characteristics and metabolic characteristics in patients with adenocarcinoma harboring ALK mutations.

Patients and Methods 

We retrospectively reviewed clinicopathologic CT and PET/CT data from patients with advanced lung adenocarcinoma screened for identifying ALK rearrangement. Lesion size, solidity, location, margins, CT attenuation, and SUV_max were assessed. Pathologic features such as differentiation, the presence of signet ring cell, EGFR/KRAS mutation status, and TTF-1 expression were also reviewed.

Results 

Of the screened 221 patients, 41 patients (19%) demonstrated ALK rearrangements, and these individuals were younger than the ALK-negative patients (P < 0.001) and showed significant association with no exposure to tobacco (P = 0.028). ALK-positive lung adenocarcinomas were significantly less differentiated than those without rearrangements (P = 0.005). ALK-positive tumors showed significantly higher SUV_max than ALK-negative tumors (P = 0.016). Multivariate logistic regression modeling for predicting the ALK-positive lung adenocarcinoma disclosed that lower CT attenuation and higher SUV_max were significant independent factors of ALK rearrangements (odds ratio, 0.87 and 1.06; P = 0.03 and 0.01, respectively). Receiver operating characteristic analysis showed that the area under the receiver operating characteristic curve for SUV_max/CT attenuation ratio was 0.788, and the optimal cutoff value of SUV_max/CT attenuation ratio for identifying ALK-positive lung adenocarcinoma was greater than or equal to 0.208 (sensitivity, 74.2%; specificity, 81.0%).

Conclusions 

This study shows that ALK-rearranged lung adenocarcinoma represents younger age, no history of smoking, the absence of spiculation on CT, and higher SUV_max/CT attenuation greater than or equal to 0.208 compared with those without ALK mutation.