ESTRO 2024 - Abstract Book

S273

Brachytherapy - Gynaecology

ESTRO 2024

Cervical cancer staging systems do not incorporate all clinical and radiological findings pertaining to the primary tumor. T-score is a novel tool for prognostic and predictive characterization of tumors undergoing chemoradiation including image guided brachytherapy (IGABT). It is based on clinical examination and MRI at diagnosis (DG) and BT. Involvement of cervix, left and right parametrium, vagina, bladder, ureters, rectum, and uterine corpus are scored with 0 to 3 points. The sum constitutes the T-score, which has prognostic value and can be used as tool for treatment adaptations [1]. T-score interpretation variability could impact the reliability of the concept, and has not been analyzed so far. We aimed to assess the T-scoring uncertainties, and how they are impacted by observers’ training.

Material/Methods:

Nine radiation oncology residents with limited gynecologic oncology experience from 3 institutions determined T score of 7 cervical cancer patients at DG and BT, based on the MRI reports and images, and clinical reports and drawings. FIGO stage was IIB and IIIB in 3 and 4 patients, respectively. Reference median T-score, determined by the experts was 8 (6-13) at DG and 7 (1-12) at BT. Attempt A: The observers determined the T-scores after 1 week of self-learning. Following a 2-months break, a structured online course was provided by the experts, including 9 presentations of 1.5 hours’ total duration, and a 12-questions’ pre- and post-course knowledge test. The pre-and post-course test questions were identical, summarizing the most important learning points. The course was followed by Attempt B of T-score determination for the same 7 cases. At both attempts, controlled conditions with a time limit of 120 minutes were required for scoring. Observers’ T-score was compared with the reference. The impact of teaching was assessed by comparing the A and B attempts and knowledge test results. Variables were compared with kappa statistics and T-test. P value <0.05 was the limit of significance.

Results:

All observers completed pre- and post-course knowledge test. Median test score improved from 25% (25-67%) before the course to 71% (42-100%) after the course (p<0.001). Median absolute and relative difference between the pre- and post-course score test was 38% (17-75%) and 113% (50-300%), respectively. Before the course, 1/9 (11%) observers achieved a test score of ³50%, while 8/9 (89%) passed this mark after completing it. However, the significant improvement of theoretical knowledge did not translate into a significant increase of accuracy of T score rating. Case-specific T-scores of observers and the reference T-scores are presented in Table 1.