title: Branch duct intraductal papillary mucinous neoplasms: does cyst size change the tip of the scale? A critical analysis of the revised international consensus guidelines in a large single-institutional series.
abstract: OBJECTIVE
  The aim of this study was to critically analyze the safety of the revised guidelines, with focus on cyst size and worrisome features in the management of BD-IPMN.
  
  
  BACKGROUND
  The Sendai guidelines for management of branch duct (BD) intraductal papillary mucinous neoplasm (IPMN) espouse safety of observation of asymptomatic cysts smaller than 3 cm without nodules (Sendai negative). Revised international consensus guidelines published in 2012 suggest a still more conservative approach, even for lesions of 3 cm or larger. By contrast, 2 recent studies have challenged the safety of both guidelines, describing invasive carcinoma or carcinoma in situ in 67% of BD-IPMN smaller than 3 cm and in 25% of "Sendai-negative" BD-IPMN.
  
  
  RESULTS
  Review of a prospective database identified 563 patients with BD-IPMN. A total of 240 patients underwent surgical resection (152 at the time of diagnosis and 88 after being initially followed); the remaining 323 have been managed by observation with median follow-up of 60 months. No patient developed unresectable BD-IPMN carcinoma during follow-up. Invasive cancer arising in BD-IPMN was found in 23 patients of the entire cohort (4%), and an additional 21 patients (3.7%) had or developed concurrent pancreatic ductal adenocarcinoma. According to the revised guidelines, 76% of resected BD-IPMN with carcinoma in situ and 95% of resected BD-IPMN with invasive cancer had high-risk stigmata or worrisome features. The risk of high-grade dysplasia in nonworrisome lesions smaller than 3 cm was 6.5%, but when the threshold was raised to greater than 3 cm, it was 8.8%, and 1 case of invasive carcinoma was found.
  
  
  CONCLUSIONS
  Expectant management of BD-IPMN following the old guidelines is safe, whereas caution is advised for larger lesions, even in the absence of worrisome features.
authors.affiliation: Departments of *Surgery †Pathology ‡Gastroenterology and §Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
authors.forename: Klaus
authors.initials: K
authors.lastname: Sahora
authors.forename: Mari
authors.initials: M
authors.lastname: Mino-Kenudson
authors.forename: William
authors.initials: W
authors.lastname: Brugge
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Thayer
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Ferrone
authors.forename: Dushyant
authors.initials: D
authors.lastname: Sahani
authors.forename: Martha B
authors.initials: MB
authors.lastname: Pitman
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Warshaw
authors.forename: Keith D
authors.initials: KD
authors.lastname: Lillemoe
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Fernandez-del Castillo
mesh_terms: D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002278:Carcinoma in Situ / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D010180:Pancreatectomy; D010181:Pancreatic Cyst / Q000401:mortality / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D010183:Pancreatic Ducts / Q000473:pathology*; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000601:surgery / Q000628:therapy*; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D015996:Survival Rate; D047368:Tumor Burden; D057832:Watchful Waiting