ESTRO 2024 - Abstract Book

S2529

Clinical - Urology

ESTRO 2024

When acute G3+ lymphopenia (yes/no) was comprised among potential variables, it was maintained as an additional independent predictor [HR= 4.343, 95%CI 1.894-9.956, p=5*10 -4 ] and performance statistics (average precision: 0.50, 0.07; F1 score: 0.4, 0.05; ROC curve AUC: 0.88, 0.02; McFadden’s pseudo -R-squared: 0.31, 0.05) slightly improved. Youden's index maximum value determined the optimum cut-off values for the risk of late G2+ lymphopenia, being ALC at baseline≤1835.4cc and craniocaudal extent>12mm. Figure1 shows the plot of risk of 2 -year G2+ lymphopenia against baseline ALC (continuous) stratified for smoking and craniocaudal extent>12mm from the lower edge of L5.

Conclusion:

G2+ lymphopenia two years after RT-end is present in a non-negligible fraction of patients, mostly modulated by baseline ALC. Since craniocaudal extent emerged among the independent predictors, considering the adoption of BM-sparing techniques, mainly in the lumbosacral region, should be a major issue to ponder.

Keywords: Hematological toxicity, Lymphopenia, PCa

References:

Current study was supported by a grant from AIRC (Associazione Italiana Ricerca Cancro) – Investigational Grant #14603.

[1] C. Sini, Dose – volume effects for pelvic bone marrow in predicting hematological toxicity in prostate cancer radiotherapy with pelvic node irradiation, Radiotherapy and Oncology, Volume 118, Issue 1, 2016, Pages 79-84, ISSN 0167-8140, https://doi.org/10.1016/j.radonc.2015.11.020.