Role of endoscopic ultrasonography guided fiducial marker placement in gastrointestinal cancer

Purpose of reviewDose escalation radiation therapy such as those delivered by stereotactic body radiation therapy (SBRT) has shown to improve local disease control in multiple types of malignancies. This requires fiducial placement to improve accuracy of treatment and avoid adverse events to adjacent radiosensitive organs during respiration phases. The purpose of this review is to provide updates of recent high-quality articles related to endoscopic ultrasonography (EUS)-guided fiducial placement for gastrointestinal malignancies, particularly in pancreatic cancer, which is expected to be the second leading cause of cancer-related deaths in the USA within this decade.Recent findingsA recent systematic review and meta-analysis has shown that EUS-guided fiducial placement for gastrointestinal malignancies has excellent technical success and safety profile. Comparative studies of most commercially available fiducial types via a 22-gauge needle system showed that a 0.035mm diameter and 10mm long gold fiducial with coiled configuration, hollow core and external helical design might be favoured due to its most balanced performance of visibility, artifact and migration.SummaryA fine balance of performance characteristics of fiducials should be discussed with radiation oncologists to select a suitable and preferred type of fiducials. The comparative studies of other newly developed platinum fiducials and liquid fiducial are pending.