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TOPLINE:

In a large cohort study, patients with low-risk pancreatic cystic lesions had a pancreatic cancer incidence of 1.89 per 1000 person-years — 14 times higher than the general population. Many diagnoses occurred more than 5 years after the initial lesion detection.

METHODOLOGY:

• Pancreatic cystic lesions can be precursors to cancer but are also present in about half the population. As imaging use has increased, so has incidental detection of pancreatic cysts. Most of those lesions are considered “low risk,” but precise estimates of the cancer risk have been lacking, and guidelines on surveillance vary considerably.
• To address that gap, researchers evaluated records from nearly 500,000 patients who underwent abdominal CT or MRI at one large Massachusetts healthcare system between 2009 and 2021. They identified 6064 patients with low-risk pancreatic cystic lesions and a mean follow-up of 3.3 years.
• The outcome was incidence of pancreatic cancer, defined as pathologically confirmed adenocarcinoma, invasive mucinous neoplasms, or high-grade dysplasia, with censoring defined as absence of pancreatic cancer on imaging follow-up for more than 1 year after the initial lesion detection.
• Multivariable cause-specific Cox proportional hazards regression models assessed associations between baseline demographic, clinical, and imaging characteristics and cancer incidence.

TAKEAWAY:

• Among the 6064 patients with low-risk lesions, 38 (0.6%) developed pancreatic cancer — for an incidence of 1.89 cases per 1000 person-years. That is roughly 14-fold higher than the general population rate of 0.14 cases per 1000 person-years.
• Of the 38 patients diagnosed with pancreatic cancer, 26 (68.4%) had cancer arising from the cyst site, while 12 (31.6%) developed cancer in a different region of the pancreas. Overall, 10 patients (26.3%) were diagnosed more than 5 years after the initial lesion detection.
• In multivariable analysis, larger cyst size was associated with pancreatic cancer development (2-3 cm vs < 1 cm; hazard ratio [HR], 5.61), as was main pancreatic duct ectasia (HR, 2.84) and older age (HR, 1.04).
• Compared with a risk stratification model that included cyst size only, adding older age (≥ 70 years) significantly improved estimation of pancreatic cancer risk. Currently, the study authors noted, most guidelines stratify surveillance based on cyst size alone, though some also incorporate age and comorbidities to refine risk estimates.

IN PRACTICE:

“This cohort study found that low-risk [pancreatic cystic lesions] were associated with a sustained long-term pancreatic cancer risk and were best stratified by combining clinical and imaging factors,” the study authors wrote. Because one quarter of cancers were diagnosed more than 5 years after lesion detection, they added, longer follow-up may be warranted to reduce missed or delayed diagnoses.

SOURCE:

The study, led by Arya Haj Mirzaian, MD, MPH, of Brigham and Women’s Hospital, Harvard Medical School, Boston, was published online in JAMA Network Open.

LIMITATIONS:

The retrospective design introduced variability in follow-up intervals and durations. The study relied on imaging-based diagnosis without histopathologic confirmation for most low-risk lesions because they are typically managed without surgery. The cohort was derived from a single healthcare system and most patients were White, which may limit generalizability. The analysis focused on baseline characteristics; future studies that include longitudinal changes in cysts might improve risk assessment.

DISCLOSURES:

Several co-authors reported financial relationships with various commercial sources, and one co-author received grants from the Agency for Healthcare Research and Quality during the conduct of the study. Full disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.