Incidental, Small (< 3 cm), Unilocular, Pancreatic Cysts: Factors That Predict Lesion Progression during Imaging Surveillance

Abstract

ObjectiveTo explore the features that predict size increase and development of potential malignant features in incidentally detected, unilocular cystic pancreatic lesions (CPLs) less than 3 cm in diameter, during subsequent follow-up.Materials and MethodsWe retrieved data of patients diagnosed with unilocular CPLs less than 3 cm in diameter during the period from November 2003 through December 2014, using a computerized search. All serial CT and MR images were analyzed to identify the number, size, and location of CPLs; dilatation of the main pancreatic duct; and occurrence of worrisome features and high-risk stigmata of malignancy in the lesion. The characteristics of CPLs were compared between the increase (i.e., size increase during subsequent follow-up) and no-increase groups. For CPLs in the increase group, subgroup analysis was performed according to the lesion size at the last follow-up (< 3 cm vs. ≥ 3 cm).ResultsAmong 553 eligible patients, 132 (23.9%) had CPLs that increased in size, and 421 (76.1%) had CPLs that did not, during follow-up. Of the 132, 12 (9.1%) CPLs increased to diameters ≥ 3 cm at the final follow-up. Among the various factors, follow-up duration was a significant independent factor for an interval size increase of CPLs (p < 0.001). In the increase group, initial cyst size was a significant independent factor to predict later size increase to or beyond 3 cm in diameter (p < 0.001), and the initial cyst diameter ≥ 1.5 cm predicted such a growth with a sensitivity and specificity of 83% and 72%, respectively. No significant factors to predict the development of potential malignant features were identified.ConclusionFollow-up duration was associated with an interval size increase of CPLs. Among the growing CPLs, initial cyst size was associated with future lesion growth to and beyond 3 cm.

Development of a stratification tool to identify pancreatic intraductal papillary mucinous neoplasms at lowest risk of progression

“…Cyst size being an independent predictor of progression comes as no surprise, given that a size of 3 centimetres or greater is defined as a worrisome feature and therefore incorporated in our composite endpoint. However, it has been shown in other cohorts that initial cyst size is a predictor of cyst growth, development of other worrisome features, and malignancy . The predictive value of cyst multifocality has been described less often, but is not a new finding.…”

Follow-up of Incidentally Detected Pancreatic Cystic Neoplasms: Do Baseline MRI and CT Features Predict Cyst Growth?

“…Third, the minimum imaging follow-up period for inclusion was 12 months; thus, size change assessment in some individuals was limited. Fourth, our study included PCNs with cross-modality follow-up (CT or MRI) that could theoretically lead to some perceived or measured size differences, given the different spatial resolutions of CT and MRI (19,31,32). Furthermore, we excluded patients with a familial predisposition of PCNs; thus, our conclusions cannot be extended to PCNs in patients with a known predisposition to having pancreatic cysts.…”

International external validation of a stratification tool to identify branch‐duct intraductal papillary mucinous neoplasms at lowest risk of progression

“…38%) and somewhat larger at diagnosis (14 vs. 12 mm). Initial cyst size and multifocality have been identified as predictors for growth and the development of WFs in both our cohorts and others, 32,[34][35][36][37] and therefore, this difference could (partially) explain why the validation cohort had a higher percentage of patients developing WFs than the development cohort (20% vs. 13%). Nevertheless, both differences are small and therefore may not represent a clinically relevant difference.…”