Dose-Volume Predictors for Patient-reported Late Diarrhoea, Faecal Incontinence and Urgency after Pelvic Radiotherapy.

AIMS: Pelvic radiotherapy adds significantly to the curative treatment of many pelvic malignancies. However, this cure comes at a cost for many patients, where late bowel toxicities, such as faecal incontinence, urgency and diarrhoea, adversely affect quality of life. Despite the implementation of advanced radiotherapy techniques in many centres, there are deficiencies in our knowledge of how to make best use of these techniques to minimise these late toxicities, with dose-volume constraints specifically for late effects needing definition. The aims of this study were to establish dose-volume predictors for patient-reported late bowel toxicities and derive constraints for clinical use to reduce the risk of these toxicities. MATERIALS AND METHODS: All radiotherapy patients treated in our institution between 2012 and 2014 for gynaecological and urological cancers (bladder, prostate where pelvic nodes are treated) were identified. Patients were sent patient-reported toxicity questionnaires at 12 and 24 months after treatment. Planning computed tomography scans were retrospectively contoured with different definitions of bowel as organs at risk (OARs). Dose-volume data for each OAR were collected and predictors of these toxicities found using multivariate analysis. For those dose-volume predictors found to be significant on multivariate analysis, statistically significant and clinically relevant dose-volume constraints were derived. Furthermore, data collected were used to validate constraints from published studies. RESULTS: Faecal urgency, incontinence and diarrhoea rates were found in 52, 23.5 and 18.7% of the 203 patients included at 12 months following radiotherapy. Dose-volume parameters for sigmoid colon and large bowel were significant for these toxicities, and constraints for these OARs were derived, which are promising. A previously published constraint for bowel loops was validated with our data. CONCLUSIONS: The sigmoid colon and large bowel are important OARs for the development of faecal urgency, incontinence and diarrhoea. Promising constraints for these OARs were derived, which require further validation before prospective clinical use.

Computed tomography versus magnetic resonance imaging in high-dose-rate prostate brachytherapy planning: The impact on patient-reported health-related quality of life.

PURPOSE: High-dose-rate (HDR) prostate brachytherapy uses volumetric imaging for treatment planning. Our institution transitioned from computed tomography (CT)-based planning to MRI-based planning with the hypothesis that improved visualization could reduce treatment-related toxicity. This study aimed to compare the patient-reported health-related quality of life (hrQOL) and physician-graded toxicity outcomes of CT-based and MRI-based HDR prostate brachytherapy. METHODS: From 2016 to 2019, 122 patients with low- or intermediate-risk prostate cancer were treated with HDR brachytherapy as monotherapy. Patients underwent CT only or CT and MRI imaging for treatment planning and were grouped per treatment planning imaging modality. Patient-reported hrQOL in the genitourinary (GU), gastrointestinal (GI), and sexual domains was assessed using International Prostate Symptom Score and Expanded Prostate Cancer Index Composite Short Form-26 questionnaires. Baseline characteristics, changes in hrQOL scores, and physician-graded toxicities were compared between groups. RESULTS: The median follow-up was 18 months. Patient-reported GU, GI, and sexual scores worsened after treatment but returned toward baseline over time. The CT cohort had a lower baseline mean International Prostate Symptom Score (5.8 vs. 7.8, p = 0.03). The other patient-reported GU and GI scores did not differ between groups. Overall, sexual scores were similar between the CT and MRI cohorts (p = 0.08) but favored the MRI cohort at later follow-up with a smaller decrease in Expanded Prostate Cancer Index Composite Short Form-26 sexual score from baseline at 18 months (4.9 vs. 19.8, p = 0.05). Maximum physician-graded GU, GI, and sexual toxicity rates of grade ≥2 were 68%, 3%, and 53%, respectively, with no difference between the cohorts (p = 0.31). CONCLUSION: Our study shows that CT- and MRI-based HDR brachytherapy results in similar rates of GU and GI toxicity. MRI-based planning may result in improved erectile function recovery compared with CT-based planning.

Patient-reported outcomes and health-related quality of life in prostate cancer treated with a single fraction of high dose rate brachytherapy combined with hypofractionated external beam radiotherapy.

AIMS: High dose rate (HDR) brachytherapy offers a highly conformal approach to radiotherapy delivery, enabling dose escalation. We report our experience using a combined HDR boost and external beam radiotherapy (EBRT) approach and its associated toxicity and effect on quality of life. MATERIALS AND METHODS: Patients with intermediate- or high-risk prostate cancer were treated with a single fraction HDR boost and EBRT between July 2008 and March 2010. Patient-reported toxicity data were collected at baseline and regular intervals after radiotherapy using International Prostate Symptom Score and Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic scales (LENT-SOMA) questionnaires; health-related quality of life data were captured by the Expanded Prostate Cancer Index Composite (EPIC) questionnaire. RESULTS: Ninety-five patients received an HDR boost of 12.5 Gy followed by EBRT delivered as 37.5 Gy in 15 fractions over 3 weeks. The International Prostate Symptom Score peaked 6 weeks after radiotherapy (median value: 9). The LENT-SOMA bladder/urethra mean baseline score was 0.35 and peaked 6 weeks after radiotherapy (mean = 0.59). Difficulties with urinary flow and frequency were the most common reported symptoms. LENT-SOMA rectum/bowel mean scores at baseline were 0.24 and peaked after 6 months (mean = 0.37). Bowel urgency was the most common reported toxicity. EPIC urinary scores returned to baseline values at 6 months and bowel median scores recovered after 24 months. There were no statistically significant associations between patient or dosimetric parameters and patient-reported outcomes. CONCLUSION: A combined HDR boost and hypofractionated EBRT regimen offers a well-tolerated method of dose escalation with acceptable levels of patient-reported toxicity.