Conversion surgery for BRCA-mutated pancreatic ductal adenocarcinoma with liver metastasis treated with platinum-based chemotherapy followed by olaparib.

Background: With recent dramatic developments in chemotherapy, attempts to incorporate surgery into the multidisciplinary treatment of unresectable pancreatic ductal adenocarcinoma with metastasis (UR-M PDAC) have emerged. Maintenance therapy with olaparib after chemotherapy including a platinum-based regimen, which inhibits the poly ADP-ribose polymerase (PARP) involved in DNA repair, was approved for UR-M PDAC with positive BRCA mutations.

Case presentation: A 47-year-old male patient with a high carbohydrate antigen 19-9 (CA19-9) level was diagnosed with PDAC in the pancreatic tail. Staging laparoscopy revealed occult liver metastasis. Because BRCA2 mutation was confirmed, triple combination chemotherapy with SOXIRI (S-1/oxaliplatin/irinotecan) was introduced and continued for 16 weeks, followed by 14 weeks of olaparib. After that, CA19-9 was normalized, and no obvious liver metastases of any size could be seen on imaging studies during chemotherapy. Since staging laparoscopy after chemotherapy proved that the liver metastasis had disappeared, laparoscopic distal pancreatectomy was performed, and curative resection was completed. After adjuvant chemotherapy with olaparib for 12 months, the patient is alive 36 months from his initial diagnosis and 27 months postoperatively without recurrence.

Conclusion: We report a case of PDAC with liver metastasis and BRCA mutation-positivity who underwent conversion surgery and achieved long-term survival after irinotecan-based chemotherapy followed by maintenance therapy with olaparib.