CA19-9 Response to First-Line Neoadjuvant FOLFIRINOX and Second-Line Gemcitabine/Nab-Paclitaxel for Patients with...

Area of Science:

• Oncology
• Gastroenterology
• Medical Oncology

Background:

• Response to second-line neoadjuvant therapy in operable pancreatic cancer is not well-studied.
• This study investigates carbohydrate antigen 19-9 (CA19-9) response to first-line and second-line chemotherapy regimens.

Purpose of the Study:

• To evaluate the efficacy of first-line (1L) and second-line (2L) neoadjuvant chemotherapy in operable pancreatic cancer (PC).
• To assess the role of CA19-9 response in predicting treatment outcomes for PC patients.

Main Methods:

• Identified operable PC patients with elevated CA19-9 (≥35 U/mL) and normal bilirubin (<2 mg/dL) receiving 1L FOLFIRINOX (FFX).
• Patients were restaged after 2 months; response determined by tumor size reduction on CT or ≥50% CA19-9 decline with preserved performance status.
• Subsequent treatment involved continuing FFX or switching to gemcitabine/nab-paclitaxel (GnP) for total neoadjuvant therapy.

Main Results:

• Of 108 patients receiving 1L FFX, 76 (70%) continued FFX and 32 (30%) switched to GnP.
• Among patients switching to GnP, 27 had no response to 1L FFX; 26 (96%) responded to 2L GnP.
• After 4 months, CA19-9 response rates were 82% for FFX continuation versus 97% for GnP switch (p=0.04).

Conclusions:

• Lack of biochemical response (CA19-9) to 2 months of 1L FFX may identify a subgroup with a high response rate to 2L GnP.
• Assessing treatment response at 2-month intervals is crucial for optimizing neoadjuvant therapy in operable pancreatic cancer.