Current recommendations for surveillance and surgery of intraductal papillary mucinous neoplasms may overlook some patients with cancer.
BACKGROUND
The 2012 Sendai Criteria recommend that patients with 3 cm or larger branch duct intraductal papillary mucinous neoplasms (BD-IPMN) without any additional "worrisome features" or "high-risk stigmata" may undergo close observation. Furthermore, endoscopic ultrasound (EUS) is not recommended for BD-IPMN <2 cm. These changes have generated concern among physicians treating patients with pancreatic diseases. The purposes of this study were to (i) apply the new Sendai guidelines to our institution's surgically resected BD-IPMN and (ii) reevaluate cyst size cutoffs in identifying patients with lesions harboring high-grade dysplasia or invasive cancer.


METHODS
We retrospectively reviewed 150 patients at a university medical center with preoperatively diagnosed and pathologically confirmed IPMNs. Sixty-six patients had BD-IPMN. Pathologic grade was dichotomized into low-grade (low or intermediate grade dysplasia) or high-grade/invasive (high-grade dysplasia or invasive cancers). Fisher's exact test, chi-square test, student's t test, linear regression, and receiver operating characteristic (ROC) analyses were performed.


RESULTS
The median BD-IPMN size on imaging was 2.4 cm (interquartile range 1.5-3.0). Fifty-one (77 %) low-grade and 15 (23 %) high-grade/invasive BD-IPMN were identified. ROC analysis demonstrated that cyst size on preoperative imaging is a reasonable predictor of grade with an area under the curve of 0.691. Two-thirds of high-grade/invasive BD-IPMN were <3 cm (n = 10). Compared to a cutoff of 3, 2 cm was associated with higher sensitivity (73.3 vs. 33.3 %) and negative predictive value (83.3 vs. 80 %, NPV) for high-grade/invasive BD-IPMN. Mural nodules on endoscopic ultrasound (EUS) or atypical cells on endoscopic ultrasound-fine needle aspiration (EUS-FNA) were identified in all cysts <2 and only 50 % of those <3 cm. Forty percent of cysts >3 cm were removed based on size alone.


CONCLUSIONS
Our results suggest that "larger" size on noninvasive imaging can indicate high-grade/invasive cysts, and EUS-FNA may help identify "smaller" cysts with high-grade/invasive pathology.
Department of Surgery, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave, CHS 72-215, Los Angeles, CA, 90095, USA.
Andrew H
AH
Nguyen
Paul A
PA
Toste
James J
JJ
Farrell
Barbara M
BM
Clerkin
Jennifer
J
Williams
V Raman
VR
Muthusamy
Rabindra R
RR
Watson
James S
JS
Tomlinson
O Joe
OJ
Hines
Howard A
HA
Reber
Timothy R
TR
Donahue
D000368:Aged; D021441:Carcinoma, Pancreatic Ductal / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D003560:Cysts / Q000000981:diagnostic imaging* / Q000473:pathology*; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D018297:Neoplasms, Cystic, Mucinous, and Serous / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D010180:Pancreatectomy; D010183:Pancreatic Ducts; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy*; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D047368:Tumor Burden; D057832:Watchful Waiting