Diagnosis of pancreatic ductal carcinoma / Шинэ санаа Шинэ нээлт

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal type of gastrointestinal cancer, with a 5-year survival rate of 5%; it remains a significant, unresolved therapeutic challenge. Its aggressive features include insidious presentation, unresectability due to early involvement of major vessels, debilitating symptoms at the late stage and de novo chemoresistance. However, according to the Japan Pancreatic Cancer Registry, the 5-year survival of UICC Stages 0 and 1a are 85.8% and 68.7%, respectively. Early diagnosis plays an important role in improving the overall survival of patients with PDAC; therefore, efforts should focus on early diagnosis and the reliable identification of patients who will most likely benefit from major surgical intervention. Patients with risk factors, including family history, accompanying disease, diabetes mellitus, chronic pancreatitis and intraductal papillary mucinous neoplasms (IPMN), should be followed up for early detection of PDAC. In Japan, a national team has undertaken such surveillance of patients with IPMN. The protocol comprises a semi-annual follow up using various modalities to detect not only IPMN carcinoma, but also PDAC concomitant with IPMN. I will address this protocol in detail. The most accurate imaging technique for PDAC diagnosis and staging is considered to be contrast-enhanced computed tomography (CECT). Whereas CT should be the first choice in patients with suspected PDAC, endoscopic ultrasound (EUS) is the most accurate, particularly for detecting small lesions (< 10 mm). EUS combines the potential of endoscopy, which enables visualization of the mucosal surface of the gastrointestinal (GI) tract, with ultrasonography. Thus, EUS is able to provide detailed, high-resolution images of the pancreas. However, whether a lesion is malignant or benign is unable to be discriminated solely from EUS imaging features. Obtaining samples from suspicious lesions or lymph nodes using EUS-guided fine-needle aspiration (FNA), offers the potential for cytological or histological diagnoses of pancreatic lesions with high sensitivity and specificity. Since accurate preoperative evaluation is essential to select the appropriate management strategy, the roles of EUS and EUS-FNA are crucial. Stage 0 PDAC (carcinoma in situ) has recently been discovered. This stage of PDAC is unable to be diagnosed using EUS-FNA, because EUS-FNA is only applicable after PDAC forms a cancerous mass (worse than stage1). Thus, diagnostic methods other than imaging require development. Presently, endoscopic retrograde pancreatography (ERP) combined with cytology is able to detect Stage 0 PDAC, and in Japan, nasopancreatic drainage tubes have recently been used to collect pancreatic juice for cytodiagnosis. I would also like to introduce this method.