BACKGROUND: The classic endpoints in cancer clinical trials typically include tumour control rate, overall survival, or disease-free survival; however, it is becoming essential to consider the impact of cancer treatments on patients' quality of life (QoL) (1,2). Cancer researchers have used different methods to assess the effectiveness of therapeutic interventions according to their influences on health-related QoL (3,4). As with other cancer treatments, while radiotherapy (RT) can benefit cancer patients, its side effects can negatively impact QoL (5). Patients undergoing pelvic radiotherapy frequently develop acute gastrointestinal (GI) and genitourinary (GU) toxicities during treatment (6,7). If aware, the multidisciplinary team can manage ongoing problems patients are experiencing. This includes medical management, nutritional support and advice, and referral to other specialties (8). To date, most studies on toxicities from pelvic RT have used clinician-reported outcomes (CROs) for reporting intra-treatment assessments and guiding clinical practice and symptom management, but recent research shows that PROs better capture the quality of life issues that patients care about. In addition, consideration of patient-reported outcomes (PROs) leads to increased cancer treatment tolerance, reduced emergency room visits, earlier detection of recurrences, and improved survival (9,10). To our knowledge, there is no published prospective data assessing the association of CROs with PROs for GI/GU toxicities and QoL in patients undergoing radiation therapy to the pelvis. Therefore, there is a need to objectively examine how RT affects QoL in this patient group.

RATIONALE: Most patients who have radical pelvic RT as a treatment for cancer experience some degree of GI and GU toxicities (6,7). Anticipation, identification, and correct management of symptoms may significantly improve the QoL for those patients. This work aims to incorporate patient's voices during treatment and enhance the communication between patients and physicians, improve patients quality of life, and help early detection of adverse events All patients receiving standard or hypofractionated pelvic RT for the first time at the McGill University Health Centre Radiation Oncology clinic are eligible. Patients will complete, through a mobile application (Opal) and in real-time, validated electronic PRO questionnaires about acute GI/GU toxicities and QoL. These questionnaires will be administered at baseline, after each visit during RT, and at two subsequent time points, i.e., at two weeks and three-month follow-up visits. We will document data on any need for further assessment, prescriptions, emergency room visits, or admissions. The treating physician will fill in the traditional intra-treatment forms simultaneously.

ANALYSIS PLAN: Patient and treatment demographics will be summarized using proportions of categorical variables. We will perform a descriptive analysis for all GI/GU symptoms reported through patient and clinician questionnaires and assess the association between PROs and CROs over time using Somers' D statistic, Bowker's Symmetry test, and multilevel random effects regression models.

HYPOTHESIS: We hypothesize significant discordance between PROs and CROs when assessing GI/GU toxicities of pelvic RT and that CROs alone are insufficient in measuring GI toxicities as they fail to capture the impact on patients' quality of life. The study findings will assess the need for improved GI/GU symptom assessment and support the creation of a new algorithm that includes both patient and clinician input. In addition, physicians can influence the patients' quality of life by anticipating the problems and toxicities that need additional care, which they can appropriately expedite.