Continuing pancreas cyst surveillance indefinitely is reasonable
BY LAUREN G. KHANNA, MD, MS
Pancreas cysts remain a clinical challenge. The true incidence of pancreas cysts is unknown, but from MRI and autopsy series, may be up to 50%. Patients presenting with a pancreas cyst often have significant anxiety about their risk of pancreas cancer. We as a medical community initially did too; but over the past few decades as we have gathered more data, we have become more comfortable observing many pancreas cysts. Yet our recommendations for how, how often, and for how long to evaluate pancreas cysts are still very much under debate; there are multiple guidelines with discordant recommendations. In this article, I will discuss my approach to patients with a pancreas cyst.
NYU Langone Health
Dr. Lauren Khanna
At the first evaluation, I review available imaging to see if there are characteristic features to determine the type of pancreas cyst: IPMN (including main duct, branch duct, or mixed type), serous cystic neoplasm (SCA), mucinous cystic neoplasm (MCN), solid pseudopapillary neoplasm (SPN), cystic neuroendocrine tumor (NET), or pseudocyst. I also review symptoms, including abdominal pain, weight loss, history of pancreatitis, and onset of diabetes, and check hemoglobin A1c and Ca19-9. I often recommend magnetic resonance cholangiopancreatography (MRCP) if it has not already been obtained and is feasible (that is, if a patient does not have severe claustrophobia or a medical device incompatible with MRI). If a patient is not a candidate for treatment should a pancreatic malignancy be identified, because of age, comorbidities, or preference, I recommend no further evaluation.
Where cyst type remains unclear despite MRCP, and for cysts over 2 cm, I recommend endoscopic ultrasound (EUS) for fluid sampling to assist in determining cyst type and to rule out any other high-risk features. In accordance with international guidelines, if a patient has any concerning imaging features, including main pancreatic duct dilation >5 mm, solid component or mural nodule, or thickened or enhancing duct walls, regardless of cyst size, I recommend EUS to assess for and biopsy any solid component and to sample cyst fluid to examine for dysplasia. Given the lower sensitivity of CT for high-risk features, if MRCP is not feasible, for cysts 1-2 cm, I recommend EUS for better evaluation.
If a cyst is determined to be a cystic NET; main duct or mixed-type IPMN; MCN; or SPN; or a branch duct IPMN with mural nodule, high-grade dysplasia, or adenocarcinoma, and the patient is a surgical candidate, I refer the patient for surgical evaluation. If a cyst is determined to be an SCA, the malignant potential is minimal, and patients do not require follow-up. Patients with a pseudocyst are managed according to their clinical scenario.
Many patients have a proven or suspected branch duct IPMN, an indeterminate cyst, or multiple cysts. Cyst management during surveillance is then determined by the size of the largest cyst and stability of the cyst(s). Of note, patients with an IPMN also have been shown to have an elevated risk of concurrent pancreas adenocarcinoma, which I believe is one of the strongest arguments for heightened surveillance of the entire pancreas in pancreas cyst patients. EUS in particular can identify small or subtle lesions that are not detected by cross-sectional imaging.
If a patient has no prior imaging, in accordance with international and European guidelines, I recommend the first surveillance MRCP at a 6-month interval for cysts <2 cm, which may offer the opportunity to identify rapidly progressing cysts. If a patient has previous imaging available demonstrating stability, I recommend surveillance on an annual basis for cysts <2 cm. For patients with a cyst >2 cm, as above, I recommend EUS, and if there are no concerning features on imaging or EUS, I then recommend annual surveillance.
While the patient is under surveillance, if there is more than minimal cyst growth, a change in cyst appearance, or development of any imaging high-risk feature, pancreatitis, new onset or worsening diabetes, or elevation of Ca19-9, I recommend EUS for further evaluation and consideration of surgery based on EUS findings. If an asymptomatic cyst <2 cm remains stable for 5 years, I offer patients the option to extend imaging to every 2 years, if they are comfortable. In my experience, though, many patients prefer to continue annual imaging. The American Gastroenterological Association guidelines promote stopping surveillance after 5 years of stability, however there are studies demonstrating development of malignancy in cysts that were initially stable over the first 5 years of surveillance. Therefore, I discuss with patients that it is reasonable to continue cyst surveillance indefinitely, until they would no longer be interested in pursuing treatment of any kind if a malignant lesion were to be identified.
There are two special groups of pancreas cyst patients who warrant specific attention. Patients who are at elevated risk of pancreas adenocarcinoma because of an associated genetic mutation or a family history of pancreatic cancer already may be undergoing annual pancreas cancer screening with either MRCP, EUS, or alternating MRCP and EUS. When these high-risk patients also have pancreas cysts, I utilize whichever strategy would image their pancreas most frequently and do not extend beyond 1-year intervals. Another special group is patients who have undergone partial pancreatectomy for IPMN. As discussed above, given the elevated risk of concurrent pancreas adenocarcinoma in IPMN patients, I recommend indefinite continued surveillance of the remaining pancreas parenchyma in these patients.
Given the prevalence of pancreas cysts, it certainly would be convenient if guidelines were straightforward enough for primary care physicians to manage pancreas cyst surveillance, as they do for breast cancer screening. However, the complexities of pancreas cysts necessitate the expertise of gastroenterologists and pancreas surgeons, and a multidisciplinary team approach is best where possible.
Dr. Khanna is chief, advanced endoscopy, Tisch Hospital; director, NYU Advanced Endoscopy Fellowship; assistant professor of medicine, NYU Langone Health. Email: Lauren.Khanna@nyulangone.org. There are no relevant conflicts to disclose.
References
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Del Chiaro M et al. Gut. 2018 May;67(5):789-804
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