ESTRO 2024 - Abstract Book

S695

Clinical - Breast

ESTRO 2024

intersection of identified subregion within each OARs, together with clinical, and treatment variable were compared using the Akaike Information Criterion (AIC) (SPSS v.29).

Results:

No failures in DIR were identified, with NCC varying between 0.89 and 0.99 (where 1 indicates perfect image similarity). Significant sub-regions where dose was associated with breast, arm and shoulder pain at post-RT were identified within the central breast region, partially overlapping major pectoralis, and axillary lymph node level 1 (Figure 2). A region associated with persistent pain at one and two years was found only in the central breast region. Mean EQD 2 of the identified region within the breast was associated with acute and persistent breast, arm and shoulder pain at one-year, whereas acute pain of arm and shoulder was related to mean EQD 2 of the identified region at the axillary lymph node level 1 ( p <0.05). Age was associated with acute and persistent pain at one and two years at breast, arm and shoulder while RT technique (fractionation, boost dose, irradiation technique), menopausal, and adjuvant chemotherapy were related to acute breast pain ( p <0.05). AIC of model including mean and maximum EQD 2 of identified region within OARs decreased by 2, considered a significant change, for breast pain at one year, arm and shoulder pain at post-RT, and one-year post-RT, indicating better discrimination.