Intraoperative Nodule Localization in Non-Small-Cell Lung Cancer: Existing and Emerging Techniques

As thoracic surgeons more frequently address smaller lung lesions and perform lung-sparing resections, their objective is to resect an adequate specimen and margin without removing excess healthy lung tissue. Although perioperative lung nodule localization has been in practice for decades, the existing and emerging techniques used for the identification of targeted and occult lesions are more widely utilized today than they were in the past. In this review, we detail the logic behind this increase in use, classify the techniques into preoperative and intraoperative categories, and define the specific modalities available. Where applicable, we review the published data comparing techniques, detailing efficacy and safety. In the preoperative space, we describe standard computed tomography (CT)-guided localization, virtual-assisted lung mapping, electromagnetic navigation bronchoscopy, robotic-assisted bronchoscopy, and novel fiducial markers. In the intraoperative space, we describe classical localization techniques, novel applications of intraoperative cone-beam CT, and fluorescence-guided surgery and intraoperative molecular imaging (IMI). Lastly, we review emerging approaches for intraoperative molecular imaging including a report on agents in early-stage clinical trials and a brief survey of promising preclinical models. With each approach mentioned, we analyze the potential benefits and hazards, and appraise the evidence for (or against) the use of any specific modality.