Background Ambulatory palliative care clinics are associated with improved outcomes in cancer patients, including short-term quality of life. However, their impact on individual patient-reported symptoms is not well understood.

Aim We evaluated the impact of ambulatory palliative care on individual symptoms in adult cancer patients.

Design Following a standard protocol (PROSPERO: CRD42022321909), investigators independently identified randomised and non-randomised intervention studies that assessed patient-reported symptom scores using validated symptom assessment scales longitudinally. Data were synthesised using random-effects meta-analyses.

Data sources Database of PubMed, CINAHL, EMBASE, PsycINFO and Cochrane Central was searched from inception to September 2023 for eligible studies.

Results 20 studies encompassing 4 prospective cohort studies, 1 randomised control trial and 15 retrospective studies were included. Most studies focused on cohorts with advanced cancers of mixed primary tumour type, were colocated within or linked to a tertiary cancer centre and assessed symptoms using the Edmonton Symptom Assessment Scale (ESAS). The meta-analyses confirmed evidence for improvement in pain (standardised mean difference (SMD) 0.31, 95% CI 0.18 to 0.44), anxiety (SMD 0.31, 95% CI 0.12 to 0.49), fatigue (SMD 0.31, 95% CI 0.10 to 0.51), insomnia (SMD 0.29, 95% CI 0.15 to 0.42), depression (SMD 0.25, 95% CI 0.09 to 0.40), drowsiness (SMD 0.23, 95% CI 0.11 to 0.34), well-being (SMD 0.28, 95% CI 0.12 to 0.45) and overall symptom burden (SMD 0.29, 95% CI 0.22 to 0.36). There was no evidence for improvement in nausea (SMD 0.19, 95% CI −0.02 to 0.40), dyspnoea (SMD 0.16, 95% CI 0.02 to 0.29) and appetite scores (SMD 0.14, 95% CI −0.00 to 0.29).

Conclusions Ambulatory palliative care had positive effects on multiple common symptoms. The strength of this evidence however is low, largely due to the considerable heterogeneity among included studies. Further research could determine thresholds on symptom assessment scales to guide urgency of referral, timing of follow-up and optimal multidisciplinary staff involvement.