A. M. Awe1, V. Rendell3, M. Lubner2, E. Winslow3 1University Of Wisconsin,School Of Medicine & Public Health,Madison, WI, USA 2University Of Wisconsin,Department Of Radiology,Madison, WI, USA 3University Of Wisconsin,Department Of Surgery,Madison, WI, USA
Introduction: Determining an appropriate surveillance strategy for pancreatic cysts (PC) presents a challenge due to management guideline heterogeneity and a relatively poor ability to predict the malignant potential of PCs. Current management protocols use maximum axial diameter (MAD) to steer treatment; however, other measures may better capture the evolution of PCs. The aim of this study is to determine whether MAD is an appropriate surrogate measure for volume and surface area of PCs.
Methods: A single-institution retrospective analysis of patients with radiologically confirmed PCs was conducted. Patients with a PC >1cm and a contrast-enhanced CT or MR scan were included. Patients with pancreatic pseudocysts, underlying pancreatitis, genetic syndromes, or solid tumors were excluded. MAD, volume, and surface area data were collected using HealthMyne, a novel lesion detecting software. Pearson’s correlations were used to determine associations between volume and MAD, and surface area and MAD for total patients and size sub-groups from the Fukuoka guidelines for PC surveillance and treatment.
Results: In total, 202 patients were included in the analysis. The MADs of the cysts ranged from 1.0 cm to 7.5 cm. PC volume as a function of the MAD for all PC sizes had a strong correlation of r=0.94. When sub-grouped by size based on the Fukuoka guidelines, correlations with volume varied: 1-2 cm (n=87), 2-3 cm (n=61), and >3 cm (n=54) PCs had correlations of 0.78, 0.53, 0.90, respectively (Fig. 1A-C). Volumes ranged for 1-2 cm cysts from 0.3- 3.8 cm3, for 2-3 cm cysts from 1.1- 10.8 cm3, and for >3 cm cysts from 6.7- 104.3 cm3. Based on volume alone, 95 cysts (47%) overlapped in Fukuoka size groupings. PC surface area as a function of the MAD for all PC sizes had a strong correlation of r=0.96. When sub-grouped by Fukuoka guideline size, correlations varied: 1-2 cm (n=87), 2-3 cm (n=61), and >3 cm (n=54) had correlations of 0.80, 0.56, 0.92, respectively (Fig. 1D-F). Surface area ranged for 1-2 cm cysts from 0.2- 13.2 cm2, for 2-3 cm cysts from 7.3- 29.6 cm2, and for >3 cm cysts from 19.6- 126.2 cm2. Based on surface area alone, 77 cysts (38%) overlapped between axial diameter size groupings in the Fukuoka guidelines.
Conclusion: Overall, there is strong correlation between PC volume, surface area and MAD, suggesting that unidimensional size is an appropriate surrogate measure. However, grouping PCs based on the Fukuoka guideline size criteria reveals poor volume and surface area correlation with MAD for small cysts. This suggests volume and surface area may be a useful adjunct measurements to guide surveillance and treatment decisions for smaller PCs.
