Background and Objective Pancreatic cancer (PC) is a significant cause of cancer-related mortality, with limited curative options and high rates of cachexia, a debilitating syndrome associated with poor prognosis. While previous research has linked sarcopenia to poor outcomes in PC, the correlation between cachexia and treatment outcomes remains underexplored. This meta-analysis aims to investigate the association between cachexia and overall survival and time to treatment failure in advanced PC patients undergoing first-line chemotherapy. Method A systematic search of electronic databases was conducted following PRISMA guidelines. Eligible studies compared cachexic and non-cachexic PC patients, reporting outcomes of observed survival or time to treatment failure. Data extraction and analysis were performed using Comprehensive Meta-Analysis Version 3.3, employing random-effects models and sensitivity analyses to assess heterogeneity and bias. Results Seven observational studies involving 2834 PC patients were included. The incidence of cachexia was 45% (95% CI: 0.27-0.65), with a higher prevalence in East Asian populations. Cachexic patients experienced significantly earlier treatment failure (SDM: −2.22, 95% CI: −2.6 to −1.7, P = 0.0001) and higher mortality risk (HR: 2.02, 95% CI: 1.17-3.48, P = 0.011) compared to non-cachexic patients. Overall survival was lower in cachexic patients (SDM: −2.34, 95% CI: −3.7 to −0.90, P = 0.001), with considerable heterogeneity across studies. Meta-regression analysis revealed significant differences between countries but insignificant correlations with age. Conclusion Cachexia is associated with reduced overall survival, early chemotherapy failure, and elevated mortality in advanced PC patients undergoing first-line chemotherapy. Recognition and management of cachexia are crucial for optimizing treatment outcomes and improving patient survival. Future research should focus on prospective studies to better understand the impact of cachexia on treatment response and develop tailored interventions to mitigate its adverse effects.