Multi-Institutional Stereotactic Body Radiation Therapy Incident Learning: Evaluation of Safety Barriers Using a Human Factors Analysis and Classification System

Abstract

Objectives: Stereotactic body radiation therapy (SBRT) can improve therapeutic ratios and patient convenience, but delivering higher doses per fraction increases the potential for patient harm. Incident learning systems (ILSs) are being increasingly adopted in radiation oncology to analyze reported events. This study used an ILS coupled with a Human Factor Analysis and Classification System (HFACS) and barriers management to investigate the origin and detection of SBRT events and to elucidate how safeguards can fail allowing errors to propagate through the treatment process.

Methods: Reported SBRT events were reviewed using an in-house ILS at 4 institutions over 2014-2019. Each institution used a customized care path describing their SBRT processes, including designated safeguards to prevent error propagation. Incidents were assigned a severity score based on the American Association of Physicists in Medicine Task Group Report 275. An HFACS system analyzed failing safeguards.

Results: One hundred sixty events were analyzed with 106 near misses (66.2%) and 54 incidents (33.8%). Fifty incidents were designated as low severity, with 4 considered medium severity. Incidents most often originated in the treatment planning stage (38.1%) and were caught during the pretreatment review and verification stage (37.5%) and treatment delivery stage (31.2%). An HFACS revealed that safeguard failures were attributed to human error (95.2%), routine violation (4.2%), and exceptional violation (0.5%) and driven by personnel factors 32.1% of the time, and operator condition also 32.1% of the time.

Conclusions: Improving communication and documentation, reducing time pressures, distractions, and high workload should guide proposed improvements to safeguards in radiation oncology.

Figure 1.

Example care path, with the Treatment Planning Section expanded to highlight all specific steps and safeguards within the care path stage. CMD = certified medical dosimetrist, PHY = medical physicist, MD = attending/resident physician, RTT = radiation therapist, RN = registered nurse, Admin = administration specialist, MQ = Elekta MOSAIQ® treatment management system, QCL = quality checklist (a Mosaiq specific list of tasks assigned to certain working groups), DOS = dosimetry working group within Mosaiq, TPS = treatment planning system.

Figure 2.

Pipe diagram indicating the origin and path of the 160 pooled events from all institutions across all stages of the collaborative care path.

Figure 3.

Breakdown of the contributing factors of the unsafe acts of Table 1. With most (95.2%) unsafe acts being human error, the categories in the chart therefore mostly represent the contributing factors that increase the chances of a human error occurring.