Dosimetric correlations with urinary quality of life in patients receiving post-prostatectomy radiation therapy

Abstract

Acute urinary toxicity is well-documented in individuals receiving post-prostatectomy radiation. However, dosimetric correlations between bladder dose and acute urinary symptoms in the post-prostatectomy setting have not been well-studied. We examined the relationship between bladder dosimetry and acute changes in individual urinary symptoms among men receiving post-prostatectomy radiation therapy. Patient-reported urinary symptoms were prospectively collected for 90 consecutive prostate cancer patients receiving post-prostatectomy radiation using the validated quality of life instrument Prostate Cancer Symptom Indices. Data were collected prior to treatment and weekly during treatment. Individual symptom scores were examined and a change in severity of an individual symptom (from baseline) of ≥ 2 points was considered clinically significant. DVHs were generated for all the patients. Receiver operating characteristic curves were generated to evaluate the ability of different dose-volume metrics to identify patients who developed individual urinary symptoms during radiation treatment from those who did not. Logistic regression was used to examine the relationship between dose-volume parameters and worsening of individual urinary symptoms. Worsening of individual urinary symptoms during radiation treatment was reported by 7% (urinary flow) to 29% (urgency) of patients. The relative bladder volume receiving moderate doses of radiation was associated with urgency (AUC 0.67 for V30 Gy). Dose-volume parameters were not significantly associated with flow, frequency, nocturia, or dysuria. There is an acute worsening of urinary symptoms among men receiving modern post-prostatectomy radiation. Worsening of urgency is associated with bladder dosimetry while flow, frequency, nocturia, and dysuria are not. This data can be used during treatment planning to reduce acute urinary toxicity during post-prostatectomy radiation.