ESTRO 2024 - Abstract Book

S5964

RTT - Treatment planning, OAR and target definitions

ESTRO 2024

Statistical analyses determined these findings to be significant, with the potential exception of values relating to the CTVsv data as the sample pool was smaller (only 12 high risk patients).

Radiographers consistently contoured slightly smaller than clinicians. Despite this, they achieve a high degree of similarity with clinician volumes, with DICE 0.8+ considered “good” (Velker et al, 2013). As clinically acceptable plans were created, these volumes may be safe for planning; perhaps with an additional margin (1-2mm would encompass the majority mean distance to agreement variation) in a radiographer-led planning pathway. Radiographer-led voluming can facilitate efficient pathways in planning of between 5-16 hours, reducing burden on departments rolling out 5# SABR and enabling patients to start treatment more quickly. Under supervision, a “scan to plan” pathway with final oncologist approval could be implemented to reduce the contouring workload and delays.

Inter-observer variability between the radiographers was minimal, consistent with similar studies (Pathmanathan et al, 2019) and suggests that further radiographers could be trained to follow the PACE protocol criteria.

In conclusion, radiographer-led voluming for 5# Prostate SABR according to PACE is safe, consistent, and time efficient. Departments could consider radiographer-led planning pathways in this cohort to facilitate implementation and uptake of this technique.

Keywords: SABR, Prostate 5#, CTV

References:

MIM Software , Beachwood, Ohio.

Pathmanathan A U, McNair H A, Schmidt M A, Brand D H, Delacroix L, Eccles C L, Gordon A, Herbert T, Van As N J, Huddart R A, Tree A C (2019). Comparison of prostate delineation on multimodality imaging for MR-guided radiotherapy. British Journal of Radiology 92: 20180948. Velker V M, Rodrigues G B, Dinniwell R, Hwee J, Louie A V (2013). Creation of RTOG compliant patient CT-atlases for automated atlas based contouring of local regional breast and high-risk prostate cancers. Radiation Oncology 8:188.

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