ESTRO 2024 - Abstract Book

S2444

Clinical - Urology

ESTRO 2024

correlation coefficient (ICC) and Spearman's coefficient. ICC values of 0.8 – 1 indicated almost-perfect agreement, and p values < 0.05 were considered statistically significant.

Results:

Four observers exhibited near-perfect interobserver agreement (ICC = 0.83; 95% CI, 0.683 – 0.922). However, patients with a prostate volume > 40 cc, DIL measurements > 15mm, or SUVmax values > 10 only demonstrated substantial agreement (ICC < 0.8). Interobserver variability was not significantly influenced by factors such as DIL side, DIL zone, PSA value, or total prostate volume. Notably, while near-perfect agreement was observed, the DIL volumes determined by the radiation oncologist were significantly smaller than the median values of the three nuclear medicine specialists (p = 0.002). Additionally, PSA and SUVmax values exhibited significant correlations with patients' DIL volumes (p < 0.05).

Conclusion:

Radiation oncologists, well-versed in prostate anatomy, can proficiently utilize PSMA-PET for identifying DIL in prostate cancer patients, achieving a significant level of consensus compared to nuclear medicine specialists. Nevertheless, it should be noted that radiation oncologists may delineate a more conservative target for DIL than their nuclear medicine counterparts. Careful consideration is warranted when contouring DIL for patients with an enlarged prostate volume, longer length, or higher SUVmax value, as this may introduce variability in the definition of DIL.

Keywords: Prostate cancer, PSMA PET/CT, Intraprostatic tumor

1655

Poster Discussion

Radiation-induced T-lymphocyte Apoptosis and Prostate Radiotherapy: final data of the French trial

Olivier Riou 1 , Gilles Crehange 2 , Florence Castan 1 , Yazid Belkacemi 3 , Jean-Leon Lagrange 3 , Tan Dat NGuyen 4 , Olivier Chapet 5 , Georges Noel 6 , David Pasquier 7 , Sebastien Clippe 8 , Christophe Hennequin 9 , Sophie Gourgou 1 , Marie-Pierre F Jacquet 10 , Mahmut East Ozsahin 11 , David Azria 1 1 Montpellier Cancer Institute, Radiation Oncology, Montpellier, France. 2 Curie Institute, Radiation Oncology, Paris, France. 3 Creteil University Hospital, Radiation Oncology, Creteil, France. 4 Reims cancer center, Radiation Oncology, Reims, France. 5 Lyon Sud University Hospital, Radiation Oncology, Pierre Benite, France. 6 Strasbourg Cancer Institute, Radiation Oncology, Strasbourg, France. 7 Oscar Lambret cancer center, Radiation Oncology, Lille, France. 8 Valence Clinic, Radiation Oncology, Valence, France. 9 Saint Louis University hostinal, Radiation Oncology, Paris, France. 10 Nimes University Hospital, Radiation Oncology, Nimes, France. 11 CHUV, Radiation Oncology, Lausanne, Switzerland

Purpose/Objective: