Incidental Pancreatic Findings: When to Follow Up?

With a constant increase in volume of imaging and improvements in quality of US, CT and MRI equipment, radiologists have to deal with tsunami of incidental findings ("incidentalomas") on daily basis.^1,2 Some of these findings can be easily dismissed. Others may simulate malignancy and cause an unnecessary surgery. ³ A small subset of incidentalomas represent an asymptomatic high-risk lesions with malignant potential or cancer and will require an urgent surgical or gastroenterological referral. ¹ A significant proportion of patients with incidental lesions will need an imaging follow up. ² Assessment of incidental findings has multitudinous consequences for the patient, the referring physician, and the healthcare system. Waiting for the results of cross-sectional imaging examinations can cause an anxiety for the patient. Moreover, it can be logistically challenging to schedule follow up CTs or MRIs, as we learned during recent pandemic. The referring physician’s fear of medico-legal effects of missed cancers may lead to a ‘cascade syndrome’ of avoidable testing. ² Lastly, follow up necessitated by incidentalomas has a major financial cost for our healthcare system. This is of paramount importance in an era of skyrocketing utilization of cross-sectional imaging and accompanying challenge to ensure appropriate use of limited healthcare resources.

There is a large body of literature focused on optimal evaluation of abdominal incidentalomas. The American College of Radiology (ACR) published first white paper on management of incidental findings in 2010, followed by additional ACR white papers. The familiarity with and adherence to multiple guidelines can be a daunting task for the busy radiologist. Furthermore, differences in practice patterns between Canada and the United States add an additional layer of complexity for Canadian radiologists seeking recommendations about the management of incidentalomas. In this issue of the CARJ, Fung et al. on behalf of the Canadian Association of Radiologists (CAR) Incidental Findings Working Group present Canadian guidelines for the management of pancreatic incidentalomas, with a particular emphasis on incidental pancreatic cysts. ⁴ The CAR Incidental Findings Working Group members should be commended for providing a concise and an updated summary on this controversial topic.

Radiologists started to report more incidental pancreatic cystic lesions approximately 2 decades ago due to introduction of multi-detector CT technology (MDCT) and the proliferation of MDCT and MRI scanners. Khalid et al. noted a 20-fold increase in number of cystic pancreatic lesions detected on cross-sectional imaging over 17 years. ⁵ Reported prevalence of these lesions is 1%-2.6% on CT and 13.6%-15.9% on MRI. ¹ When radiologist makes a suggestion for the management of incidental pancreatic cystic lesion, the morphology and the size of the lesion should be considered, as well as patient’s age and co-morbidities. The CAR guidelines present common scenarios which are encountered in routine clinical practice in both academic and community settings. Recommendations on the part of the CAR working group include: (1) avoid follow up in simple pancreatic cysts smaller than 5 mm in maximal diameter; (2) establishment of an upper limit of 75 years for follow up examinations; (3) five-year surveillance limit for the majority of patients. Notably, patients with cystic lesions demonstrating worrisome features (e.g., mural nodule, focal wall thickening) or simple cysts larger than 2.4 cm should be referred to gastroenterology for additional work up potentially including endoscopic ultrasound +/- FNA due to the higher risk of mucinous neoplasm. ⁴

Given the increased frequency of detection of pancreatic incidentalomas, these evidence-based recommendations will help to ensure that patients with significant findings are not missed or lost to follow up, balanced with an avoidance of excessive imaging in patients with minimal risk of malignancy.