The prognostic value of CA19-9 response after neoadjuvant therapy in patients with pancreatic cancer: a systematic review and pooled analysis

Background Pancreatic cancer (PC) is a highly aggressive and refractory disease, with disappointing 5-year survival rates. Regarding the wide application of neoadjuvant treatment in patients with PC, how the post-neoadjuvant Carbohydrate antigen 19-9 (CA19-9) response could translate into a survival benefit is not clearly understood. We aimed to evaluate the correlation of the CA19-9 response with overall survival (OS) in patients with PC receiving neoadjuvant therapy. Methods An extensive electronic search in PubMed, Embase, and the Cochrane Library was performed to identify relevant articles, from which data relevant to independent correlations of the CA19-9 response with overall survival (OS) were extracted for analysis. A random-effects model was used to calculate the pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs). Results Altogether, 17 eligible studies were identified in the systematic review. Pooled analysis showed that CA19-9 response > 50% (HR, 0.43; 95% CI 0.29-0.56; P < 0.001) and normalization of CA19-9 (HR, 0.52; 95% CI 0.42-0.63; P < 0.001) after neoadjuvant treatment are significantly associated with promising overall survival. The results also showed that optimal CA19-9 response after neoadjuvant treatment was significantly related to a favorable prognosis (HR = 0.49, 95% CI 0.42-0.55, P < 0.001; I2 = 45.1%, P = 0.04). Subgroup analysis revealed there were no prognostic difference between CA19-9 > 50% and normalization of CA19-9 after neoadjuvant treatment (P = 0.338), but the duration of neoadjuvant chemotherapy over 4 months was significantly associated with expanded postoperative survival (P = 0.013). Conclusions Serum CA19-9 is valuable in determining the effect of neoadjuvant treatment in patients with PC. Post-neoadjuvant CA19-9 response > 50% or CA19-9 normalization was related to a more promising overall survival, suggesting that optimal CA19-9 response may be a suitable prognostic index to guide treatment decisions.