Evaluation of the Effects of Prostate Radiation Therapy on Occludin Expression and Ultrasonography Characteristics of the Bladder.

Abstract

To evaluate the effects of radiation dose in prostate radiation therapy (RT) on occludin expression and ultrasonography characteristics of the bladder. Urine samples of 64 prostate RT patients were collected before, at regular intervals during, and 3 months after RT. Occludin expression analysis was performed, and bladder wall echogenicity and echotexture were investigated by ultrasound and the gray-scale histogram analysis method. The bladder equivalent uniform dose (EUD) was derived from individually produced dose treatment plan for each patient. Clinical scoring for bladder-specific symptoms was done using the Radiation Therapy Oncology Group Acute Radiation Morbidity Scoring Criteria Scale. Thirty patients (47%) experienced at least 1 of the studied bladder symptoms (grade ≥1 endpoints), including urinary pain, frequency, urgency, straining, incontinence, hematuria, dysuria, and nocturia. For these patients there were significant changes in urine occludin levels after starting the treatment compared with the baseline urine samples (P=.023). The mean bladder EUD that caused a significant change in occludin level, which occurred after the 15th RT session, was 26.9 Gy (range, 13.2-36.5 Gy, P=.020). In all patients a significant reduction in bladder echogenicity (P=.0137) and a significant change in its echotexture (P=.047) was found after the 10th RT session, after which the EUD to the bladder reached 17.9 Gy (range, 8.8-24.3 Gy). Significant changes in occludin expression level and bladder wall echogenicity and echotexture occurred during prostate RT. Our findings suggest that a significant reduction in bladder echogenicity and increase in occludin expression during treatment can be associated with acute urinary complications.