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Langan et al. Art Int Surg 2023;3:140-6 https://dx.doi.org/10.20517/ais.2023.13 Page 3

accurately identifying high-risk cysts. The Fukuoka Consensus was found to have 83% sensitivity and 53%
specificity, which was improved over Sendai but still lacked adequate specificity. Moreover, Lee et al.
evaluated the revised guidelines for predicting malignant potential and compared the diagnostic
[12]
performance and concordance between contrasted CT and MRI . This group found that both CT and MRI
were comparable and high-risk stigmata included enhancing mural nodule > 5 mm, abrupt main pancreatic
duct caliber change, lymphadenopathy, larger main pancreatic duct size, and faster cyst growth rates; and
this is in line with what was identified as high risk in the European Guidelines . In summary, considering
[12]
the relatively high rate of malignancy in initially Sendai-negative lesions as well as the rate of concomitant
malignant lesions, more accurate criteria for clinical decision-making were warranted. In brief, this analysis
was clear that pancreatic cyst patients still needed ways of distinguishing between patients who would
benefit from an aggressive surgical approach and those who qualify for observation without the risk of
missing malignant transformation.

The European Study Group on Cystic Tumours of the Pancreas then published consensus guidelines in
2018 in Gut, which aimed to improve the diagnosis and management of pancreatic cysts . Details that were
[13]
quoted from this analysis included: (1) cyst size greater than 30 mm had a 5% risk of malignancy and
subsequent death within 3 years; (2) cyst size less than 30 mm had a 5-year risk for developing malignancy
of 45% if the cyst increases more than 2 mm per year; and (3) a cyst size increase over 5 mm per year or total
growth of 10 mm had a 20-fold higher risk of malignant progression . Additionally, absolute indications
[13]
for surgery were recommended, including positive cytology for malignancy or high-grade dysplasia, solid
mass, jaundice related to tumor, an enhancing mural nodule greater than 5 mm, or main pancreatic duct
dilation greater than 10 mm. Finally, relative surgical indications were created, including growth rate greater
than 5 mm per year, increased levels of serum CA 19-9, main pancreatic duct dilation between 5 and 9.9
mm, cyst diameter greater than 40 mm, new onset of diabetes, acute pancreatitis caused by the cyst, and an
[13]
enhancing mural nodule less than 5 mm .
Challenges of identification and surveillance
However, extraordinarily pertinent clinical questions remained. For instance, in terms of diagnostic
investigation, which modality most reliably distinguishes neoplastic from non-neoplastic cysts, and which
modality can most reliably detect high-grade dysplasia or early cancer? With respect to surveillance, what is
cost-effective surveillance of cysts, which risk factors for progression need to be considered, and what is the
optimal modality and follow-up scheme for patients after partial pancreatectomy for resection of IPMN? In
other words, how can the pancreatic cyst community better identify and risk stratify mucinous cysts?

Attiyeh et al. in 2018 explored this topic of risk stratification. Using prospectively maintained data from
three high-volume institutions, Memorial Sloan Kettering Cancer Center, Johns Hopkins and the Mayo
Clinic, the authors sought to identify more accurate markers of high-grade dysplasia or carcinoma to help
avoid unnecessary surgery or support potentially curative intervention . Most patients (69%-77%) who met
[14]
high imaging risk criteria for branch duct IPMN and underwent surgical resection were found to have low-
risk disease on pathology (1,028 resected IPMN specimens). The authors concluded that the consequences
of overestimating the risk of malignancy based on imaging criteria should not be understated as
pancreaticoduodenectomy continues to be associated with a 2%-4% risk of mortality and a 20%-25% risk of
major morbidity at high-volume institutions . Therefore, improving our ability to predict high-risk
[14]
mucinous pancreatic cysts would no doubt improve clinical care.

Another topic of controversy in the mucinous pancreas cyst population is the length of follow-up needed
after surgical resection / partial pancreatectomy. Efishat et al. assessed the rates, patterns and predictors of