Resectable Pancreatic Cancer with CA19-9 > 500 U/mL: A Biological Indicator for Survival Benefit with Intensive Neoadjuvant Chemotherapy.

BACKGROUND

While anatomical resectability guides pancreatic cancer treatment, carbohydrate antigen (19-9 (CA19-9) serves as a biological indicator of disease burden. Current guidelines suggest considering neoadjuvant chemotherapy (NAC) for cases with markedly elevated CA19-9, but specific threshold values and treatment strategies remain undefined. This retrospective study aimed to evaluate the efficacy of intensive NAC using gemcitabine plus nab-paclitaxel or fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) for anatomically resectable pancreatic cancer with elevated CA19-9 (> 500 U/mL).

PATIENTS AND METHODS

We analyzed patients with anatomically resectable pancreatic cancer and CA19-9 > 500 U/mL treated between 2014 and 2022. Initial planned treatments were either 4-month intensive NAC followed by surgery (NAC group) or upfront surgery (UPS group). Survival outcomes were evaluated using retrospective intention-to-treat analysis.

RESULTS

Among 184 included patients, 46 received NAC and 138 underwent upfront surgery. The NAC group demonstrated significantly improved overall survival compared with the UPS group (median 52.7 vs. 22.7 months, P < 0.001). Resection rates were 89.1% and 76.1% in the NAC and UPS groups, respectively. Among resected cases, the NAC group achieved higher lymph node-negative resection rates (53.7% vs. 23.8%, P < 0.001) and better post-resection CA19-9 normalization rates (75.6% vs. 56.1%, P = 0.037). Survival benefits were maintained even in cases with CA19-9 > 2000 U/mL (median OS 52.7 vs. 18.9 months, P = 0.025).

CONCLUSIONS

CA19-9 > 500 U/mL serves as an effective indicator for implementing intensive NAC in anatomically resectable pancreatic cancer. This biomarker-based strategy effectively extracts the beneficial group from NAC, prolonging survival outcomes through better systemic disease control.