From the Guidelines
To monitor IPMN, MRI is the preferred imaging modality for follow-up, with EUS used in selected cases, as recommended by the European evidence-based guidelines on pancreatic cystic neoplasms 1.
Monitoring Strategy
For low-risk IPMNs (< 3 cm, no worrisome features):
- Perform MRI/MRCP every 6-12 months for the first 2 years
- If stable, extend to every 1-2 years thereafter For higher-risk IPMNs (≥ 3 cm or worrisome features):
- Conduct MRI/MRCP every 3-6 months
- Consider endoscopic ultrasound (EUS) with fine-needle aspiration annually Additional monitoring recommendations:
- Annual clinical evaluation for symptoms (abdominal pain, weight loss, jaundice)
- Serum CA 19-9 testing annually
- Continue surveillance indefinitely, as IPMNs can progress over many years
Rationale
Monitoring is crucial because IPMNs have malignant potential, and regular imaging allows for early detection of changes in size, morphology, or the development of worrisome features that may indicate progression to pancreatic cancer 1. MRI/MRCP is preferred due to its high sensitivity and lack of radiation exposure. EUS provides detailed imaging and allows for tissue sampling if needed, and its use is supported by guidelines such as those from the American College of Radiology 1. The surveillance interval is based on the risk stratification of the IPMN, with more frequent monitoring for higher-risk lesions.
Key Considerations
- The European evidence-based guidelines on pancreatic cystic neoplasms recommend lifelong surveillance following resection of an IPMN, with follow-up imaging using MRI or EUS 1.
- The American Gastroenterological Association suggests that patients with pancreatic cysts <3 cm without a solid component or a dilated pancreatic duct undergo MRI for surveillance in 1 year and then every 2 years for a total of 5 years if there is no change in size or characteristics 1. However, the most recent and highest quality study, the European evidence-based guidelines on pancreatic cystic neoplasms 1, recommends MRI as the preferred imaging modality for follow-up, which takes precedence over other recommendations.
From the Research
Monitoring Intraductal Papillary Mucinous Neoplasms (IPMN)
To monitor IPMN, several methods can be employed, including:
- Endoscopic ultrasound (EUS) with or without fine-needle aspiration (FNA) to assess the morphology of cysts and identify high-risk characteristics 2
- Contrast-enhanced multidetector computed tomography (MDCT) to differentiate IPMN from other cystic lesions and attribute them to branch duct or main duct IPMN 3
- Magnetic resonance imaging (MRI) in combination with magnetic resonance cholangiopancreatography (MRCP) to depict the fine architecture of cystic tumors 3
- Periodic surveillance at 6-12 month intervals for small and asymptomatic branch duct IPMNs 3
Factors to Consider in Monitoring IPMN
Several factors should be considered when monitoring IPMN, including:
- Cyst size, as larger cysts are more likely to be malignant 4, 5
- Presence and size of mural nodules, as these are associated with an increased risk of malignancy 4, 6
- Main pancreatic duct (MPD) diameter, as dilation of the MPD is associated with an increased risk of malignancy 4, 6
- Thickened or enhancing cyst wall, as these features are associated with an increased risk of malignancy 6
- Lymphadenopathy, as this is associated with an increased risk of malignancy 6
Surveillance Intervals
The optimal surveillance interval for IPMN is unknown, but it is recommended that patients be followed at least annually with history and physical and optimal cross-sectional imaging 5. The surveillance interval should be decreased and the extent of testing increased based on patients with higher oncologic risk stratification 5.
Imaging-Based Models
Imaging-based models can be used to predict the malignant potential of IPMN, and these models perform comparably to international consensus guidelines 6. These models can help determine surgical candidacy for patients with IPMNs and allow for appropriate treatment decision-making 6.