A large multicenter study of recurrence after surgical resection of branch-duct intraductal papillary mucinous neoplasm of the pancreas.

BACKGROUND: Surgery for pancreatic branch-duct intraductal papillary mucinous neoplasm (BD-IPMN) is indicated for therapy of symptomatic patients and to prevent development of invasive cancer. There is currently no consensus on management of BD-IPMN patients after surgical resection. The aim of this retrospective multicenter study was to determine the recurrence and long-term survival after surgical resection of BD-IPMN and to determine the predictive factors of recurrence.

METHODS: All patients who underwent surgery for BD-IPMN from 2005 to 2011 at 2 centers were identified. The diagnosis of BD-IPMN was based upon imaging and endosonographic analysis, and was confirmed by pathological analysis. The lesions were classified into 4 categories according to the WHO classification. Data on cyst characteristics, operative procedure, recurrence, and follow-up were evaluated. Recurrence was defined as the presence of BD-IPMN or mass in the remnant pancreas after surgery as seen on follow-up imaging. Recurrence suspected on imaging was confirmed via histological analysis when possible.

RESULTS: A number of 271 patients (67% female; mean age 63.4 yrs) with BD-IPMN underwent surgical resection. The mean size of the cyst was 24.2mm (range, 12-80). There were 34 (12.5%) patients with an associated mass. 82 (30.3%) patients had worrisome features in the cyst on pre-operative EUS, included mural nodules (N.=25), solid component (N.=27), debris (N.=25), and a dilated major pancreatic duct (N.=5). 144(53%) patients had a pancreaticoduodenectomy for head lesions, 125 (46%) had distal pancreatectomy for tail/body lesions, and 1 (1%) underwent a total pancreatectomy. Histology showed 86% with noninvasive IPMN (adenoma 31%, moderate dysplasia 24%, severe dysplasia or carcinoma in situ 31%) and 14% with invasive IPMN. The mean patient follow-up was 28 months (range, 10-180 months). Recurrence in the remnant pancreas occurred in 34 (12.5%) patients. Of the patients with recurrence, 3/34 had invasive carcinoma and 31/34 had noninvasive cystic lesions; all patients with invasive carcinoma recurrence were those with a previous invasive IPMN. On MVA, risk factors for cyst recurrence were severe dysplasia/intraductal carcinoma in situ and invasive IPMN even after adjusting for elevated CEA (>193 ng/mL), type of surgery, and cyst size (OR 2.8, 95% CI=1.1-7.3; P=0.028). 3 patients who had invasive IPMN and 1 who had severe dysplasia patient with recurrence died, all because of recurrent cancer, with the mean time from recurrence to death being 36 months.

CONCLUSIONS: The risk of BD-IPMN recurrence after resection depends upon the histological type, with the highest-risk groups being those with severe dysplasia/intraductal carcinoma in situ and invasive IPMN. Even after negative resection margins, the pancreatic remnant still harbors a risk of recurrence which requires long-term surveillance.