Rapid Growth Rates of Suspected Pancreatic Cyst Branch Duct Intraductal Papillary Mucinous Neoplasms Predict Malignancy.
BACKGROUND
The majority of branch duct intraductal papillary mucinous neoplasms (BD-IPMNs) are recommended for surveillance imaging based on consensus guidelines. However, growth rates that should prompt concern for malignant transformation of BD-IPMN are unknown.


OBJECTIVE
To determine whether BD-IPMN growth can predict an increased risk of malignancy and define growth rates concerning for malignant BD-IPMN.


METHODS
The study is a retrospective, multicenter study of suspected BD-IPMN patients undergoing imaging surveillance. All patients underwent EUS evaluation followed by surveillance imaging.


RESULTS
Two hundred and eighty-four patients with suspected BD-IPMN without worrisome features or high-risk stigmata were followed for a median 56 months and underwent a median of four imaging studies. Nine patients (3.2 %) developed malignant BD-IPMN. Malignant BD-IPMN grew at a faster rate (18.6 vs. 0.8 mm/year; P = 0.05) compared to benign BD-IPMN. BD-IPMN growth rate between 2 and 5 mm/year was associated with an increased risk of malignancy with hazard ratio (HR) of 11.4 (95 % CI 2.2-58.6) when compared to subjects with BD-IPMN growth rate <2 mm/year (P = 0.004). BD-IPMN growth rate ≥5 mm/year had a hazard ratio of 19.5 (95 % CI 2.4-157.8) (P = 0.005). BD-IPMN growth rate of 2 mm/year had a sensitivity of 78 %, specificity of 90 %, and accuracy of 88 % to identify malignancy. Total BD-IPMN growth was also associated with increased risk of malignancy (P = 0.003) with all malignant IPMNs growing at least 10 mm prior to cancer diagnosis.


CONCLUSIONS
BD-IPMN growth rates ≥2 mm/year and total growth of ≥10 mm should be considered worrisome features for BD-IPMN at increased risk of malignancy.
Division of Gastroenterology, University of California San Diego Health Sciences, 9500 Gilman Drive (MC 0956), La Jolla, CA, 92093-0956, USA, wilsontkwong@gmail.com.
Wilson T
WT
Kwong
Robert D
RD
Lawson
Gordon
G
Hunt
Syed M
SM
Fehmi
James A
JA
Proudfoot
Ronghui
R
Xu
Andrew
A
Giap
Raymond S
RS
Tang
Ingrid
I
Gonzalez
Mary L
ML
Krinsky
Thomas J
TJ
Savides
D000230:Adenocarcinoma / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D019160:Endosonography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000000981:diagnostic imaging / Q000473:pathology*; D010181:Pancreatic Cyst / Q000473:pathology; D010183:Pancreatic Ducts; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D011159:Population Surveillance; D012372:ROC Curve; D012189:Retrospective Studies; D047368:Tumor Burden