Computed tomography in the assessment of cartilage invasion in locally advanced laryngeal cancer

Introduction
In laryngeal cancer, accurate assessment of the laryngeal cartilage is essential to ensure correct staging, prognosis, and treatment. This is especially important given organ preservation in cases with cartilage involvement.

Aim of the research
To assess the sensitivity, specificity, and positive and negative predictive values (positive predictive value (PPV), negative predictive value (NPV)) of computed tomography (CT) in detecting cartilage involvement. A second aim was to determine whether the time from the CT scan to surgery influences CT reliability.

Material and methods
We retrospectively reviewed data from 233 patients who underwent total laryngectomy from 2007 to 2018 at our institution. We compared the CT findings to the histopathological results to determine the CT reliability in terms of identifying the presence of cartilage invasion and in staging.

Results
In the full cohort, CT performance was as follows: sensitivity, 68.8%; specificity, 60.3%; PPV, 65.6%; and NPV, 63.8%. In the subgroup of patients (n = 68) who underwent surgery 14 days or fewer after the CT scan, the corresponding values were as follows: sensitivity, 82.1%; specificity, 57.5%; PPV, 57.5%; and NPV, 82.1%. CT staging was accurate in 53.2% of cases; postoperative histopathologic evaluation led to upstaging in 73 (31.3%) cases and downstaging in 34 (14.6%).

Conclusions
The novel findings of this study show that CT imaging is most accurate when performed no more than 14 days prior to surgery, suggesting that surgery should be performed ≤ 14 days after imaging to maintain the best accuracy of CT. Given the limited reliability of CT in detecting cartilage invasion, complementary imaging techniques such as magnetic resonance imaging and/or ultrasound should be performed in ambiguous cases.