The overall level of physical and psychological symptom burden of advanced cancer patients (ACP) in an outpatient setting is notoriously difficult to assess. Therefore, more efficient and objective assessment is needed to accomplish this important task. The aim of this study was to compare the physical and psychological symptom burden rated by palliative care nurse (PCN) versus patient's self-rating. This retrospective German cohort study analyzed symptom burden using an electronic patient-reported outcome measure (ePROM). After referral to an outpatient specialized palliative care team, a PCN assessed the patient's symptoms both up to three months before initial presentation (IP) and at IP.Group differences were identified using analyses of variance (ANOVA). Further descriptive analysis of patient characteristics was used. The study enrolled 164 ACP who were referred to a specialized palliative care (SPC) team. Mean age was 62 (± 12.6) years. Gastrointestinal (n = 46; 28.0%), lung (n = 32; 19.5%), and breast cancer (n = 34; 20.7%) were the most common entities. Most frequent reasons for referral were pain (n = 55; 33.5%) and social care problems (n = 36; 22.0%). Patients reported significantly higher grades on depression (n = 144; Z = -2.8, p = 0.005), anxiety (n = 144; Z = -2.376, p = 0.018), and worsened general condition (n = 139; Z = -7.005, p < 0.001). ACP in an outpatient setting were more frequently referred to SPC for pain management and assistance with social problems with regard to the cancer and its limitations. Psychological distress was underrated by the PCN in comparison with patient self-reporting through ePROM. This underlines the importance of self-reported outcome measurement.