The diagnostic dilemma of highly suspicious solid pancreatic head lesions: repeated tissue diagnosis may not be necessary.

Background: For unresectable pancreatic cancer a repeat tissue diagnosis is usually required for chemotherapy, even if the 1st tissue is ‘suspicious for cancer’. We aimed to determine whether ‘suspicious’ tissue alone or in combination with a suspicious imaging and/or elevated CA19-9 might be sufficient to confirm the diagnosis of cancer. Methods: Information was gathered from a prospective database (2005-2013)for all pancreatic head lesions that underwent an EUS(Endoscopic Ultrasound) guided tissue diagnosis. Data was analysed using Microsoft Excel and IBM SPSS21. Results: 772(69.5%) of 1125 EUS-FNA patients had a suspicious solid pancreatic head lesion on initial imaging. 238(21%) patients required >1 attempt at tissue diagnosis. Suspicious cytology/histology alone had 97.2% specificity for diagnosing malignancy. Suspicious imaging + Ca19-9≥100 + suspicious cytology/histology, was 99.8% specific. Suspicious pancreatic mass with metastasis + Ca19-9 ≥800, without any histology/cytology was 99.8% specific. All of the above had sensitivities of 13.8 – 78.2%. Conclusion: A combination of a strongly suspicious imaging, a suspicious cytology or histology and CA19-9 ≥100 is highly specific(99.8%) for pancreatic adenocarcinoma or cholangiocarcinoma. Therefore such patients may not require any further tissue diagnosis. Similarly the combination of a suspicious pancreatic mass with metastatic disease on imaging and CA19-9 ≥800 is also highly specific(99.8%) and therefore such patients may not require any tissue diagnosis at all.