Voxel-Based Analysis for Identification of Urethrovesical Subregions Predicting Urinary Toxicity After Prostate Cancer Radiation Therapy.

PURPOSE: To apply a voxel-based analysis to identify urethrovesical symptom-related subregions (SRSs) associated with acute and late urinary toxicity in prostate cancer radiation therapy. METHODS AND MATERIALS: Two hundred seventy-two patients with prostate cancer treated with intensity-modulated radiation therapy/image-guided radiation therapy were analyzed prospectively. Each patient's computed tomography imaging was spatially normalized to a common coordinate system via nonrigid registration. The obtained deformation fields were used to map the dose of each patient to the common coordinate system. A voxel-based statistical analysis was applied to generate 3-dimensional dose-volume maps for different urinary symptoms, allowing the identification of corresponding SRSs with statistically significant dose differences between patients with or without toxicity. Each SRS was propagated back to each individual's native space, and dose-volume histograms (DVHs) for the SRSs and the whole bladder were computed. Logistic and Cox regression were used to estimate the SRS's prediction capability compared with the whole bladder. RESULTS: A local dose-effect relationship was found in the bladder and the urethra. SRSs were identified for 5 symptoms: acute incontinence in the urethra, acute retention in the bladder trigone, late retention and dysuria in the posterior part of the bladder, and late hematuria in the superior part of the bladder, with significant dose differences between patients with and without toxicity, ranging from 1.2 to 9.3 Gy. The doses to the SRSs were significantly predictive of toxicity, with maximum areas under the receiver operating characteristic curve of 0.73 for acute incontinence, 0.62 for acute retention, 0.70 for late retention, 0.81 for late dysuria, and 0.67 for late hematuria. The bladder DVH was predictive only for late retention, dysuria, and hematuria (area under the curve, 0.65-0.72). CONCLUSIONS: The dose delivered to the urethra and the posterior and superior parts of the bladder was predictive of acute incontinence and retention and of late retention, dysuria, and hematuria. The dose to the whole bladder was moderately predictive.

Rare cause of dysuria: eosinophilic cystitis.

Eosinophilic cystitis is an inflammatory condition characterized by eosinophilic infiltration of whole layers of the bladder wall. The condition occurs more commonly in adults. We report a case of eosinophilic cystitis mimicking a bladder tumor in a 5-year-old boy with symptoms of dysuria and urinary incontinence. The diagnosis was confirmed by histopathology and he underwent clinical treatment with trimethoprim-sulfamethoxazole and antihistamine (cetirizine). The symptoms fully resolved in follow up, which is continuing. Although very rare, eosinophilic cystitis should be considered in cases of dysuria and increased bladder wall thickness but no identified urinary tract infection.

The clinical value of sonourethrography after bipolar transurethral plasmakinetic prostatectomy.

The aim of this study was to assess the value of transrectal sonourethrography in the diagnosis of dysuria after bipolar transurethral plasmakinetic prostatectomy (TUPKP). Seventy-seven male patients with dysuria after TUPKP underwent transrectal sonourethrography. The clinical data were then compared with the surgical outcomes. The following pathologies were diagnosed: Bladder neck atresia (17/77), bladder orifice strictures (15/77), membranous urethral strictures (21/77), pars cavernosa urethral stricture (12/77), residual prostate gland (5/77), external urethral orifice stricture (2/77), calculi in the prostatic urethra (2/77), flap in the internal urethral orifice (2/77), and postoperative dysfunction of the bladder detrusor muscle (1/77). Transrectal sonourethrography is a reliable diagnostic method for numerous pathologies that occur in patients with dysuria after TUPKP and is a clinically useful tool.