Successful Conversion Surgery for Unresectable Microsatellite Instability-High Pancreatic Tail Cancer Following...

Area of Science:

• Oncology
• Immunotherapy
• Pancreatic Cancer Research

Background:

• Pancreatic cancer typically has a low prevalence of microsatellite instability-high (MSI-high) status (<1%).
• Pembrolizumab is approved for MSI-high cancers unresponsive to chemotherapy.
• This case explores pembrolizumab's efficacy in a rare MSI-high pancreatic cancer subtype.

Observation:

• A 78-year-old male with unresectable metastatic pancreatic tail cancer (UR-M) showed high MSI due to MSH2/MSH6 loss.
• Six cycles of pembrolizumab resulted in a partial response.
• Immune-related renal dysfunction led to treatment discontinuation.

Findings:

• Positron emission tomography/computed tomography revealed decreased lymph node metastasis uptake post-pembrolizumab.
• The patient underwent successful radical resection (pancreaticoduodenectomy, adrenalectomy, lymph node sampling).
• At 6 months post-surgery, the patient remains alive and recurrence-free.

Implications:

• This case demonstrates successful conversion surgery for MSI-high UR-M pancreatic cancer using pembrolizumab.
• It underscores the potential of pembrolizumab in this specific molecular subtype.
• Proactive MSI testing is crucial for identifying candidates for immunotherapy and curative surgery.