A multi-center study of 349 pancreatic mucinous cystic neoplasms: Preoperative risk factors for adenocarcinoma.

Abstract

231 Background: Pancreatic mucinous cystic neoplasms (MCN) are defined by presence of ovarian stroma per WHO 2000 classification. Given their malignant potential, current guidelines recommend resection. However, there are limited data on preoperative risk factors for adenocarcinoma (AC) and high grade dysplasia (HGD) occurring in an MCN. Methods: MCN resections from 2000-2014 at the 8 institutions of the Central Pancreas Consortium were included. Patients with and without AC/HGD were compared. Primary aims were to determine preoperative risk factors for AC/HGD in an MCN and to assess outcomes of MCN-associated AC. Results: Of 1667 resections for pancreatic cystic lesions, 349 pts (21%) had an MCN with 52 (15%) having MCN-associated AC/HGD. Male gender (29 vs 8%; p<0.001), head/neck location (39 vs 13%; p<0.001), increased MCN size (7.2 vs 4.6 cm; p=0.004), radiographic presence of a solid component/mural nodule (54 vs 20%; p<0.001), and duct dilation (43 vs 12%; p<0.001) were associated with AC/HGD compared to benign MCN. All persisted as independent predictors of MCN-associated AC/HGD (Table). AC/HGD was not associated with presence of radiographic septations or preoperative cyst fluid analysis (CEA, amylase, or mucin). Median CA19-9 for patients with AC/HGD was 210 vs 15 U/ml for those without (p=0.001). In the 44 pts with AC, 41 (93%) had lymph nodes harvested with nodal metastases in only 14 (34%). Median FU for pts with AC was 27 mos. AC recurred in 12 pts (27%) with a 3-yr RFS of 59%. OS for pts with MCN-associated AC was 64% at 3 yrs. Conclusions: Adenocarcinoma or high grade dysplasia is present in 15% of resected pancreatic mucinous cystic neoplasms. Pre-operative factors associated with AC/HGD in an MCN include male gender, head/neck location, larger MCN, solid component/mural nodule, and duct dilation on imaging. MCN-associated AC appears to have decreased LN involvement and increased RFS and OS compared to typical pancreatic ductal adenocarcinoma. [Table: see text]