Background: To summarise the prognostic value of PROs in advanced GO cancer. Methods: We searched multiple databases using search terms developed with medical librarians. Studies examining the relationship between baseline PROs and prognosis were included. Two reviewers screened articles and extracted data on study design, survival, univariable and multivariable relationships between PROs and prognosis. QUAL-SYST was used for quality assessment. Discrepancies were resolved by a third reviewer. Results: Of 3002 abstracts, seven studies were included: four pooled analyses of randomised controlled trials (RCTs), two RCTs and one cohort study. Five received QUAL-SYST scores >65%. Total 3,408 patients and 2,761(81%) with PRO data. Median survival ranged from 4.5 to 9.5 months. In one univariable analysis for oesophageal squamous cell cancer (SCC), physical functioning and fatigue measured by QLQ-C30 had prognostic significance. For adenocarcinoma, physical functioning, global QOL, role functioning, emotional functioning (QLQ-C30) were significant in three studies. Pain was significant in three studies (QLQ-C30 n=2, EQ-5D-3L n=1). Fatigue (QLQ-C30) was significant in two studies. Appetite loss (QLQ-C30) was significant in two studies. In multivariable analyses for oesophageal SCC (QLQ-C30) physical and social functioning had prognostic significance. In adenocarcinoma, physical functioning, role functioning, appetite loss, global QOL, social functioning and pain showed prognostic significance (Table). One study showed adenocarcinoma patients with lower anorexia (FAACT-A/CS scores of >37) lived longer (19.3 months) than patients with low scores ≤37 (6.7 months). Conclusions: Baseline PROs for multiple functional domains, symptoms (pain, appetite loss) and overall QOL have prognostic significance in advanced GO cancer. Further research is needed to establish clear levels of the relationship which could assist in communication with patients about prognosis, and stratification for clinical trials.