Introduction:
Serum carbohydrate antigen 19-9 (CA19-9) is routinely used in the management of pancreatic cancer for diagnosis, prognostication and surveillance purposes despite its low specificity.
Case presentation:
This case report demonstrates the challenges of interpreting elevated serum CA19.9 levels in a patient with pancreatic cancer. We performed a Whipple's procedure in an otherwise fit 78-year-old man for pancreatic adenocarcinoma. One year after surgery, he presented with a non-malignant anastomotic stricture that was associated with an elevated serum CA19-9. Subsequently, he presented with biliary sepsis secondary to an infected liver cyst. CA19-9 in the cyst fluid and serum were elevated. On both of these occasions, serum CA19-9 normalised without any clinical or radiological evidence of recurrence.
Discussion:
Despite sound clinical acumen and investigations, it may be hard to differentiate cancer recurrence from benign aetiologies. Benign conditions may cause elevation of CA19-9, even in the setting of previous malignancy. Persistently high CA19-9 level post-decompression raises suspicion of malignancy.
Conclusion:
This case serves as a reminder for clinicians that non-specific increases in CA19-9 after curative surgery is not uncommon. We recommend careful interpretation of CA19-9 levels in combination with clinical history, physical examination and radiological investigations.