Natural history of asymptomatic pancreatic cystic neoplasms

The management of asymptomatic pancreatic cysts is controversial and indications for excision are based on pathology and natural history.

This study aimed to examine outcomes of asymptomatic lesions using a protocol based on size and cyst fluid analysis.

Asymptomatic cysts were identified from a prospectively maintained database. Sequential cross-sectional imaging studies were assessed, and results of endoscopic ultrasound-guided aspiration were co-analysed.

A total of 338 asymptomatic patients underwent evaluation. Overall, 84 cysts were <1.5 cm and 254 were ≥1.5 cm in diameter. Median patient follow-up was 5.1 years [interquartile range (IQR): 4.1-6.9 years]. In the group in which cysts measured <1.5 cm in diameter, median cyst size was 1.0 cm (IQR: 0.6-1.2 cm) at presentation and increased to 1.2 cm (IQR: 0.7-1.6 cm) during follow-up. Five (6.0%) patients underwent resection, all within 2 months of presentation. In the group in which cysts measured ≥1.5 cm in diameter, median cyst size was 2.5 cm (IQR: 2.0-3.4 cm) at presentation and increased to 2.7 cm (IQR: 3.0-4.2 cm). A total of 63 (24.8%) patients underwent resection. Surgery was performed with 2 months in 53 (84.1%) patients, within 12 months in four (6.3%) patients and at >12 months post-presentation in six (9.5%) patients. A total of 70.6% of resected specimens were identified as malignancies or mucinous lesions.

Asymptomatic cysts of <1.5 cm in diameter can safely be followed by imaging and are expected to undergo little change. A quarter of all asymptomatic cysts measuring ≥1.5 cm are appropriately resected based on imaging and cyst fluid analysis.