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.