Are Diagnostic Computed Tomography Chest Scans Sufficient for Detecting Supraclavicular in Initial Breast Cancer Staging?

Abstract

<h3>Purpose/Objective(s)</h3> Initial staging workup strategies for locally advanced or suspected stage IV breast cancer can include computed tomography (CT) of the chest, abdomen, pelvis (CAP) and bone scan or, alternatively, a whole-body positron emission tomography/computed tomography (PET/CT). Variations in intravenous contrast injection site and bolus timing, arm positioning, and acquisition techniques on a CT chest scan could limit visualization of supraclavicular (SCV) and supracricoid cervical lymph nodes, which are critical for staging, prognosis, and treatment recommendations. The study's purpose is to determine whether there is a difference between the incidences of SCV and cervical lymphadenopathy detected on staging CT CAP versus PET/CT scans. <h3>Materials/Methods</h3> The records of consecutive newly diagnosed breast cancer patients who received initial staging scans at a single institution from 2012 to 2017 were reviewed in a HIPAA compliant, institutional review board-approved study. De-identified information was reviewed for inclusion: new breast cancer diagnosis, >18 years old, and availability of staging. Exclusion criteria were prior breast cancer treatment, re-staging for known recurrence, and nondiagnostic imaging examinations. Radiology reports were searched for SCV and cervical lymphadenopathy to determine the incidence detected by each imaging modality. A board certified neuroradiologist reviewed and characterized scans that noted cervical or SCV lymphadenopathy. <h3>Results</h3> The initial search resulted in 3,126 PET/CT and 631 CT CAP scans with 588 patients fulfilling the inclusion criteria. PET/CT scans had been performed in 539 patients and 49 received CT CAP and bone scans. The two groups were well matched by stage (Table 1). Metastatic cervical lymphadenopathy was detected by PET-CT in 50 patients (7.9%) versus two (3.7%) with CT CAP. Out of the 50 patients who had cervical lymphadenopathy detected by PET-CT, 30 (60%) had metastatic cervical lymphadenopathy above the level of the lung apex, the typical upper extent of a CT chest field of view. Although 25 (50%) patients had additional areas of distant metastatic disease, cervical lymphadenopathy above the thoracic inlet was the only site of distant metastasis for 13 patients (26%), and would not have been detectable by CT CAP. <h3>Conclusion</h3> PET/CT detected more cervical and SCV lymphadenopathy than CT CAP in initial staging scans for breast cancer, with 60% of those detected on PET/CTs in areas that would have been occult on standard CT chest scans. Such nodal involvement constituted the only site of distant metastatic disease in 26% of the patients. Thus, dedicated CT neck imaging may be a reasonable addition to CT CAP as an initial staging strategy to determine accurate staging and radiation treatment field volumes and borders.