Background: Incurable cancer often constitutes an enormous challenge to patients, affecting their physical and psychosocial well-being profoundly. Targeted types of treatment (early palliative care) have been developed in recent years to support people in this stage. This review summarises what is currently known about the effects of these treatments regarding improving health-related quality of life, depression, symptom intensity and survival in adults diagnosed with advanced cancer compared with treatment as usual/standard cancer care. Methods: We searched Cochrane Central Register of Controlled Trials, MEDLINE , EMBASE , CINAHL, PsycINFO and Opengrey together with three clinical trial registers and reference lists of articles. Additionally, we contacted authors of completed and on-going studies. All randomised and cluster-randomised controlled trials (RCTs) on professional palliative care services that provided palliative specialist or co-ordinated comprehensive care for patients in early advanced stages of cancer were included. The review was conducted within the Cochrane Palliative and Supportive Care Group. Results: We could include six randomised and cluster-randomised controlled trials involving 1407 participants. Three trials evaluated interventions delivered by specialized palliative care teams and the others evaluated models of coordinated care. Compared with usual cancer care alone, early palliative care significantly increased health-related quality of life with small effect size (SMD 0.17, 95% confidence interval, CI 0.02 to 0.32, participants = 1176, odds ratio = 1.36, 95% CI 1.04 to 1.79). For survival, levels of depresson and symptom intensity quality of evidence was not yet sufficient. Conclusions: Early palliative care interventions are effective for increasing quality of life in advanced cancer patients. Although we found only small effect sizes, we consider this as clinically relevant in an advanced disease stage with limited prognosis. Upcoming results from several on-going trials will improve decisions on further outcomes.