Background: The Improving Patient Experience and Health Outcomes Collaborative (iPEHOC) aims to improve health outcomes through uptake of electronic patient reported outcome measures (e-PROMs) in oncology practices in Ontario and Quebec. Building on screening with the Edmonton Symptom Assessment System (ESAS), e-PROMs were triggered based on cut scores to focus multidimensional assessment and management of pain (BPI), fatigue (CFS), anxiety (GAD-7) and depression (PHQ-9). Methods: Multifaceted implementation strategies and practice change coaching facilitated the use of e-PROMs to improve symptom outcomes. A mixed-method, pre-post quasi-experimental design assessed process and impact of the intervention on symptom screening rates, symptom burden, patient experience and activation, clinician satisfaction, team collaboration and health care use. Mann-Whitney U statistics examined significance of change from baseline to the 8-month post comparison. Qualitative data explored uptake of e-PROMs in practice. Results: Over the implementation period 10,248 ESAS screens were completed in iPEHOC clinics; 17.5% triggered an additional e-PROM. A slight improvement was noted in person-centeredness of communication (mean change of 1.43 to 1.37; four-point scale of 1 = very satisfied, 4 = very dissatisfied) and in team collaboration. A significant increase in patient activation levels (p = 0.045) was related to decreased emergency department visits (2% pre/post change, p = 0.81) and hospitalization within 30 days of an e-PROMs completion (2.2% change, p = 0.034) in Ontario. Patients and clinicians perceived e-PROMs as valuable to focus communication in the clinic visit and for shared treatment planning. Focus group data suggests that patients use e-PROMs as a ‘self-check-in’, to communicate their symptoms and normalize disclosure of depression in clinical care. Conclusions: Uptake of e-PROMs in diverse settings is complex and demanding. Improving symptom management quality requires PROM data to be fed-back for ‘real-time’ use in the clinical encounter and practice change facilitation for meaningful use in routine care.