Background: Palliative care (PC) corresponds to an approach that enhances the quality of life for patients facing life-threatening diseases, such as cancer, as well as for their families. There are various models for providing palliative care. Early referral to PC of patients with advanced cancer has a significant positive impact on their quality of life. However, the criteria for early referral still remain controversial. Objectives: To evaluate patients’ symptomatic intensity and perception of quality of life on admission to a PC unit and to analyze these two variables according to different models of approach (outpatient and inpatient care). Methods: A cross-sectional, descriptive, and correlational study was conducted with a sample of 60 patients sequentially admitted to a PC unit from palliative outpatient consultations or other inpatient services in a tertiary hospital dedicated to oncology care. The evaluation protocol included a sociodemographic and medical questionnaire, the Edmonton Symptom Assessment Scale (ESAS), and the Palliative Care Outcome Scale (POS) completed by patients within the first 24 h after admission. Results: The participants were mostly male (61.7%), with a median age of 72 years. The majority of patients (n = 32; 53.3%) were undergoing outpatient treatment, while the remaining individuals (n = 28; 46.7%) were transferred from other hospital services (inpatient care). In the outpatient care group, higher scores for fatigue and dyspnea were observed. Conversely, in the inpatient care group, higher scores were observed for pain, depression, and anxiety. There were significant differences between the two groups regarding the POS dimensions of meaning of life, self-feelings, and lost time. In the inpatient group, there was a longer time between diagnosis and referral to PC; however, it was also in the inpatient group that there was less time between PC referral and first PC evaluation, between PC referral and PC unit admission, and between PC referral and death. There were no significant correlations between referral times and ESAS/POS scores in the inpatient and outpatient groups. Conclusions: The patients admitted to the Palliative Care Unit presented a high symptom burden and changes in the perception of quality of life. However, there are no statistically significant differences between one model of approach in relation to the other. It was found that poorer symptom control and quality of life were associated with a shorter referral time for PC, because this was only initiated after curative care was suspended, particularly in our institutional context. Early referrals to the PC team are essential not only to relieve symptom-related distress but also to improve treatment outcomes and quality of life for people with cancer.