Validation of the Bone-RADS System in Spanish and Its Applicability Among Non-Radiologist Physicians With Varying Levels of Clinical Experience – A Pilot Study

Abstract

Introduction:
The timely diagnosis of malignant bone tumors using conventional radiography represents a challenge, especially for physicians without experience in orthopedic oncology or imaging. Inspired by the Bi-RADS system used for breast tumors, the Bone-RADS™ system has been proposed to classify potentially neoplastic bone lesions based on radiographic characteristics, guiding management toward either surveillance or biopsy. However, its practical validation among non-radiologist physicians—particularly in Spanish-speaking settings—is limited.

Objective:
To assess the feasibility of a validation study on the understanding, applicability, and interobserver agreement of the Spanish-translated Bone-RADS™ system among non-radiologist physicians with varying levels of clinical training.

Methodology:
A pilot study was conducted to validate the Spanish version of the Bone-RADS™ system, applied by non-radiologist physicians. The translation was performed by a specialist in Language and Literature with a master’s degree in Translation. Five groups were included: medical students, junior residents (R1–R2), senior residents (R3–R4), non-oncologic orthopedic surgeons, and an expert group (radiologists, pathologists, and orthopedic oncologists). Participants classified 20 clinical-radiological cases before and after a brief explanatory lecture. Understanding and applicability were assessed through a satisfaction survey; interobserver agreement and agreement with the final diagnosis were evaluated using sensitivity, specificity, and the kappa coefficient.

Results:
Initially, low interobserver agreement was observed in the less-experienced groups, particularly medical students, junior residents, and non-oncologic orthopedic surgeons. After the lecture, agreement improved significantly, although discrepancies persisted in interpreting margins and endosteal erosion, which were considered difficult categories. A reduction in evaluation time per case was also noted, averaging less than 2 minutes. The expert group maintained high internal agreement and was used as the diagnostic reference.

Conclusions:
High participation and completion of the protocol, along with improved interobserver agreement and a positive perception of the tool, suggest that a formal large-scale validation study is feasible. Critical areas such as margins and endosteal erosion were identified and could be addressed through targeted educational adjustments in future multicenter studies.

Keywords:
Bone-RADS™, bone tumors, radiography, clinical validation, medical education