Background: Treatment related side effects after chemotherapy are common, with significant toxicities seen in 78.2% to 98.3% of patients allocated to two study arms of a lymphoma trial [1]. While most oncology clinics provide patient education before treatment, onetime delivery of large amounts of information without reiteration of crucial facts results in information gaps, delay in seeking care, culminating in potentially avoidable ED visits and hospitalizations. Technology based symptom monitoring can facilitate early detection of complications, reduce symptom burden and cost of care. Here we update our study [2] of utility of a mobile-health tool for timely management of cancer treatment related toxicities in a community-based oncology practice. Methods: A web-based mobile application consisting of a patient interface, a provider interface and an embedded analytic platform was developed. Patient ‘check-ins’ incorporating a brief introduction and chemotherapy toxicity questionnaires are delivered through automated text or email. Toxicity questionnaires are based on the NCI-PRO-CTCAE ITEMS-ENGLISH form builder. The provider interface incorporates a ‘patient records summary’ page and a ‘tracker’ page, allowing the oncology care team to monitor responses in real-time. Responses exceeding pre-specified thresholds generate a color-coded ‘flag’ and are marked for follow up. Flags result in a phone call followed by in-person evaluation if necessary. All interventions are time stamped. Patient experience is measured concurrently using a Likert-scale as well as free-text response box. Results: 310 patients were enrolled as of January 21, 2021. Median age was 64 years. There were 49% females.8916 check-ins were sent out and 2963 responses recorded for an overall response rate of 33.23%. 531 responses provided by 109 unique patients were flagged for follow up, amounting to 6% of all responses. Fatigue was the most common symptom flagged for follow-up (454), followed by nausea/vomiting or diarrhea (167), abdominal pain (140), cough/dyspnea (140) and numbness/tingling (138). Follow up was prompt, with 60% of patient symptoms followed up on the same day and of these, 84% followed-up within 4 hours of patient reported symptom. Patient experience was consistently favorable. 72% of patients reported an experience score of ≥ 4 (1-5 scale, 5 being the most favorable). Conclusions: Electronic capture of symptoms using connected technology is feasible and can be used for timely management of treatment related complications. References: Bartlett, N.L., et al., Dose-Adjusted EPOCH-R Compared With R-CHOP as Frontline Therapy for Diffuse Large B-Cell Lymphoma: Clinical Outcomes of the Phase III Intergroup Trial Alliance/CALGB 50303. J Clin Oncol, 2019. 37(21): p. 1790-1799. Sanyal, A. Mobile health tool for monitoring cancer treatment complications. 2020. ASCO Quality Care Symposium: American Society of Clinical Oncology.