Background: Patient portals within electronic health records (EHR) have become increasingly essential in promoting patient-centered oncology care. They offer opportunities for completing symptom surveys that can aid in symptom management, facilitate patient-clinician communication, and enable health monitoring. As part of the Northwestern University Improving the Management of Symptoms During and Following Cancer Treatment (NU IMPACT) study, we examined the relationship between symptom severity, anxiety, health literacy, and shared decision-making with usage of three common features in the patient portal (portal). Methods: This study included adults diagnosed with cancer in the NU IMPACT study. Participants completed baseline surveys on socio-demographics, health literacy (Single Item Literacy Screener), anxiety (Patient-Reported Outcomes Measurement Information System; PROMIS), with high anxiety scored as ≥60 vs <60, shared decision-making (CollaboRATE), and symptom severity (Patient-Reported Outcome version of the Common Terminology Criteria for Adverse Events; PRO-CTCAE). Portal activities one year following enrollment were extracted from EHRs. Portal usage patterns of patient-initiated messages, portal lab and clinical note views were counted as number of days the activity was used over the year and categorized as tertiles. Multivariable ordinal logistic regression models were used to examine associations between survey measures and ordered tertiles of patient portal activities. Results: Participants (N=3,464) were mostly female (66%), White (85%), with a mean (SD) age of 61(13) years old. The frequency ranges of patient-initiated messages over a year were 0-163 days, labs viewed were 0-350 days, and clinical notes viewed were 0-103 days. Participants with at least one severe or very severe symptom on the PRO-CTCAE were more likely to be in higher tertiles of patient-initiated portal messages (OR: 1.37, 95% CI: 1.17-1.61), lab views (OR: 1.48, 95% CI: 1.26-1.74), and clinical note views (OR: 1.19, 95% CI: 1.01-1.40). Participants with higher levels of anxiety were more likely to be in higher tertiles of patient-initiated portal messages (OR: 1.54, 95% CI: 1.28-1.85), lab views (OR: 1.22, 95% CI: 1.01-1.46), and clinical note views (1.42, 95% CI: 1.18-1.71). Participants with higher health literacy were more likely to be in higher tertiles of patient-initiated portal messages (OR: 1.38, 95% CI: 1.09-1.74) and lab views (OR: 1.34, 95% CI: 1.06-1.69), but not note views (OR: 1.03, 95% CI: 0.82-1.30). Shared decision making was not associated with portal usage. Conclusions: Patients with greater symptom severity and anxiety may turn to the portal for symptom management. Certain features within the portal may demand a higher level of health literacy for engagement. Understanding the factors that promote and impede portal usage can help optimize cancer care delivery.