Routine Inflammatory and Hematological Markers and Acute Radiation Toxicity in Patients with Prostate Cancer

Background: Modern radiotherapy techniques have improved the safety of prostate cancer treatment, but acute gastrointestinal and genitourinary toxicity remains a common clinical problem. Early identification of patients who are likely to develop treatment-related adverse effects may help optimize supportive care. This study evaluated the relationships between clinical characteristics, radiotherapy planning parameters, systemic inflammatory biomarkers, and acute pelvic toxicity during hypofractionated radiotherapy. Materials and Methods: We retrospectively analyzed 142 patients with histologically confirmed prostate cancer who underwent external beam radiotherapy at the Provincial Integrated Hospital in Płock, Poland, between October 2024 and March 2026. Clinical, laboratory, and radiotherapy planning data were obtained from institutional electronic records. Laboratory analyses included CRP, creatinine, total leukocyte, neutrophil, lymphocyte, erythrocyte and platelet counts, hemoglobin, and hematocrit. Rectal and bladder toxicity was prospectively graded according to the RTOG/EORTC criteria at 2 and 4 weeks after treatment initiation. Correlation and multivariable regression analyses were performed to identify factors associated with acute treatment-related toxicity. Results: Radiotherapy significantly reduced leukocyte and lymphocyte counts (both p < 0.001) and produced smaller reductions in erythrocyte count, hemoglobin, hematocrit, and absolute neutrophil count (all p < 0.05). Patients who reported rectal or urinary symptoms early during treatment generally continued to experience toxicity later in the treatment course. Rectal and bladder toxicities were positively correlated, indicating that patients with toxicity affecting one pelvic organ frequently developed symptoms in the other. Routine inflammatory biomarkers and most dosimetric parameters showed limited independent value for predicting clinically relevant acute toxicity. Conclusions: Early gastrointestinal and genitourinary toxicity appears to be a useful clinical indicator of persistent treatment-related symptoms during hypofractionated prostate radiotherapy. Early rectal and bladder toxicity was associated with toxicity later during treatment, whereas routine laboratory markers and most dosimetric parameters showed limited independent associations with acute pelvic toxicity.