20.500.12556/DiRROS-24007 Sequencing of chemotherapy in total neoadjuvant treatment for rectal cancer does not predict radiation-induced lymphopenia Radiation-induced lymphopenia (RIL) is associated with an increased risk of death in solid tumors, including rectal cancer. The aim of this study was to determine whether the sequencing of chemotherapy in total neoadjuvant treatment (TNT) for rectal cancer predicts the development of RIL. Patients and methods We analyzed acute hematologic toxicity data from 53 patients who underwent TNT for locally or locoregionally advanced rectal cancer between July 2022 and April 2023. Twenty-eight patients received induction chemotherapy with capecitabine and oxaliplatin [CAPOX], and 25 received consolidation chemotherapy (6 cycles of CAPOX in both groups). The chemoradiation protocol consisted of Volumetric Modulated Arc Therapy with Simultaneous Integrated Boost Radiotherapy (VMAT-SIB RT) up to 48.4 Gy in 22 fractions, concomitantly with capecitabine twice a day (lat. bis in die, BID). The Mann-Whitney U test was performed to compare RIL between the two patient groups. Pelvic bone marrow was contoured as a non-limiting organ-at-risk to assess the received dose, and binary logistic regression was used to determine whether RIL depends on V5Gy~V42Gy or the planning target volume (PTV) size. Results Thirty-four patients (64.2%) developed RIL of any grade, which was not significantly associated with either the induction or consolidation chemotherapy TNT regimen (Wald = 3.159, p = 0.076). No significant differences were found in neutrophil counts or the neutrophil-to-lymphocyte ratio. In the logistic regression model predicting the likelihood of RIL, two variables were statistically significant: V10Gy (Wald = 4.366, p = 0.037) and V30Gy (Wald = 6.084, p = 0.014). These results indicate that V10Gy< 71% and V30Gy< 26.6% may reduce the likelihood of developing RIL. Conclusions In our study, the sequencing of chemotherapy in TNT for rectal cancer did not predict the development of RIL. However, the incidence of RIL may be reduced by applying RT dosimetric constraints to the pelvic bone marrow. radiation-induced lymphopenia rectal cancer total neoadjuvant treatment z obsevanjem povzročena limfopenija rak danke kompletno neoadjuvantno zdravljenje true false true Association of Radiology and Oncology Ljubljana Angleški jezik Slovenski jezik by Authors Neznano 2025-11-06 03:38:34 2025-11-26 10:40:57 2025-12-05 11:30:06 0000-00-00 00:00:00 2025 0 Ljubljana 0 str. 252-256 no. 2 Vol. 59 Jun. 2025 0000-00-00 Zaloznikova Objavljeno apc 2024-04-01 2024-04-17 2025-06-01 616.3 1318-2099 10.2478/raon-2025-0034 241131267 RAZ_Orazem_Miha_2025.pdf RAZ_Orazem_Miha_2025.pdf 1 B678C3D15C3FBD79EC47AFFFEA71B9BE 11b45638e9aca26a9d797ea42f6757c9f762b698705c9284da0bbbe75565f956 1db65e31-caac-11f0-94a7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=36268 Onkološki inštitut Ljubljana 0 0 0