Endoscopic ultrasound and early diagnosis of pancreatic cancer

Pancreatic cancer screening

PURPOSE

This article reviews the current evidence surrounding pancreatic cancer screening. The current targets of screening include identification of early pancreatic cancer, as well as the two most important precursor lesions; intraductal papillary mucinous neoplasm and high grade pancreatic intraepithelial neoplasia. Given the relatively low incidence of pancreatic adenocarcinoma in the general population, patients with elevated risk based on family history or an underlying genetic syndrome are felt to be the most appropriate patients to undergo screening.

METHODS

An extensive review of the literature was performed and the major findings of the available literature regarding pancreatic screening are reviewed in detail.

RESULTS

Several prospective trials have evaluated pancreatic cancer screening in high-risk groups. The results of those trials are summarized in this article. Current consensus guidelines and recommendations from the International Cancer of the Pancreas Screening Consortium Summit are also discussed.

CONCLUSIONS

The exact benefit of pancreatic cancer screening remains unclear at this time, but emerging evidence suggests that there is a window of opportunity to detect precursor lesions and early pancreatic adenocarcinomas in high-risk patient populations. Better understanding of the pathway of carcinogenesis will hopefully improve our ability to detect early, resectable pancreatic carcinomas, and provide a mortality benefit to patients at significantly elevated risk of pancreatic adenocarcinoma.

Endoscopic ultrasonography for surveillance of individuals at high risk for pancreatic cancer

Pancreatic cancer is a highly lethal disease with a genetic susceptibility and familial aggregation found in 3%-16% of patients. Early diagnosis remains the only hope for curative treatment and improvement of prognosis. This can be reached by the implementation of an intensive screening program, actually recommended for individuals at high-risk for pancreatic cancer development. The aim of this strategy is to identify pre-malignant precursors or asymptomatic pancreatic cancer lesions, curable by surgery. Endoscopic ultrasound (EUS) with or without fine needle aspiration (FNA) seems to be the most promising technique for early detection of pancreatic cancer. It has been described as a highly sensitive and accurate tool, especially for small and cystic lesions. Pancreatic intraepithelial neoplasia, a precursor lesion which is highly represented in high-risk individuals, seems to have characteristics chronic pancreatitis-like changes well detected by EUS. Many screening protocols have demonstrated high diagnostic yields for pancreatic pre-malignant lesions, allowing prophylactic pancreatectomies. However, it shows a high interobserver variety even among experienced endosonographers and a low sensitivity in case of chronic pancreatitis. Some new techniques such as contrast-enhanced harmonic EUS, computer-aided diagnostic techniques, confocal laser endomicroscopy miniprobe and the detection of DNA abnormalities or protein markers by FNA, promise improvement of the diagnostic yield of EUS. As the resolution of imaging improves and as our knowledge of precursor lesions grows, we believe that EUS could become the most suitable method to detect curable pancreatic neoplasms in correctly identified asymptomatic at-risk patients.