e18306 Background: Cancer patients are increasingly likely to visit an emergency department (ED) for acute care compared to the general population. Cancer patients who visit the ED often have long wait times, increased exposure to infection, and lesser quality treatment. The Centers for Medicare & Medicaid Services (CMS) is encouraging efforts to decrease survivor acute care visits. The purpose of this study was to examine cancer-related ED visits using a national population-based sample to understand why they are seeking care in an ED. Methods: A retrospective cohort study of U.S. patients who visited EDs between June 1, 2017 and May 31, 2018 was conducted using the National Syndromic Surveillance Program (NSSP) BioSense Platform. Cancer patients were identified using International Classification of Diseases, 10th Revision (ICD-10) codes for any cancer type and specifically for cancers of the bladder, female breast, cervix, colon and rectum, kidney, liver, lung, ovary, pancreas, prostate, or uterus. Symptoms were identified using syndromic definitions and key-word queries. Significance testing (p-value ≤0.01), was used to assess differences in the prevalence of symptoms by cancer type. Results: There were 97 million visits to EDs during the study period, 710,297 (0.8%) were among cancer survivors. Slightly more were female (50.1%) than male (49.5%); more were aged 65 or older (53.6%) than 18-64 (1.4-35.3%). The most common symptoms were pain (19%), gastrointestinal (14%), respiratory (12%), neurologic (5%), fever (5%), and injury (4%). Prevalence of symptoms differed significantly by cancer type. Some symptoms were higher among those with specific cancer types compared to all cancers in aggregate: pain (cervical, liver, pancreas); gastrointestinal (pancreas, liver, colorectal); respiratory (lung); neurologic (liver, lung), fever (pancreas, liver), injury (prostate), and bleeding (colorectal, liver). Conclusions: Use of NSSP data enabled a descriptive characterization of more than half of the U.S. ED visits among cancer patients. These comprehensive findings inform best practices to reduce unplanned acute care and help inform possible modifications in treatment and care protocols among survivors of specific cancers.