BACKGROUND AND PURPOSE - Radiotherapy (RT) induced genitourinary (GU) morbidity is typically assessed by physicians as single symptoms or aggregated scores including symptoms from various domains. Here we apply a method to group patient-reported GU symptoms after RT for localized prostate cancer based on their interplay, and study how these relate to urinary bladder dose.
MATERIALS AND METHODS - Data were taken from two Scandinavian studies (N=207/276) including men treated with external-beam RT (EBRT) to 78/70Gy (2Gy/fraction; median time-to-follow-up: 3. 6-6. 4y). Within and across cohorts, bladder dose-volume parameters were tested as predictors for GU symptom domains identified from two study-specific questionnaires (35 questions on frequency, incontinence, obstruction, pain, urgency, and sensory symptoms) using univariate and multivariate logistic regression analysis (MVA) with 10-fold cross-validation. Performance was evaluated using Area Under the Receiver Operating Characteristic Curve (Az).
RESULTS - For the identified Incontinence (2-5 symptoms), Obstruction (3-5 symptoms), and Urgency (2-7 symptoms) domains, MVA demonstrated that bladder doses close to the prescription doses were the strongest predictors for Obstruction (Az: 0. 53-0. 57) and Urgency (Az: 0. 60). For Obstruction, performance increased for the across cohort analysis (Az: 0. 61-0. 64).
CONCLUSIONS - Our identified patient-reported GU symptom domains suggest that high urinary bladder doses, and increased focus on both obstruction and urgency is likely to further add to the understanding of GU tract RT responses.
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. 2016 Feb 12 [Epub ahead of print]
Maria Thor, Caroline Olsson, Jung Hun Oh, Stine Elleberg Petersen, David Alsadius, Lise Bentzen, Niclas Pettersson, Ludvig Paul Muren, Morten Høyer, Gunnar Steineck, Joseph O Deasy
Dept of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, USA. Radiation Physics, University of Gothenburg, Sweden. , Dept of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, USA. , Depts of Medical Physics of Oncology, Aarhus University Hospital, Denmark. , Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Sweden. , Depts of Medical Physics of Oncology, Aarhus University Hospital, Denmark. , Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden. , Depts of Medical Physics of Oncology, Aarhus University Hospital, Denmark. , Depts of Medical Physics of Oncology, Aarhus University Hospital, Denmark. , Division of Clinical Cancer Epidemiology, Department of Oncology, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Sweden. , Dept of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, USA.