Incidentally found pancreatic cysts common, usually benign

Last Updated: 2017-09-21

By Will Boggs MD

NEW YORK (Reuters Health) - Nearly half of people who undergo magnetic resonance cholangiopancreaticography (MRCP) have incidentally discovered pancreatic cysts with a diameter of 2 mm or greater, according to results from the Study of Health in Pomerania (SHIP).

Pancreatic cysts are independent predictors of pancreatic cancer, but most are asymptomatic. Previous reports suggest prevalences of 2.6% on CT scan, as high as 19.6% on thick-slice MRI, and up to 50% on autopsy studies of elderly individuals.

Dr. Marie-Luise Kromrey from University Medicine Greifswald, in Germany, and colleagues used data from the prospective, population-based SHIP to assess the incidence, prevalence, and clinical outcome of incidentally detected pancreatic cysts.

Among 1,077 participants who had imaging, 494 had pancreatic cysts 2 mm or larger, for a weighted prevalence of 49.1%, according to the September 11 Gut online report.

Most (81.1%) had 1 to 5 cysts, 13.0% had 6 to 10 cysts, 3.8% had 11 to 20, and 2.2% had more than 20. Nearly two-thirds of the cysts (63.6%) were <5 mm; only 0.7% were >20 mm.

"Only about 6% of cysts and 2.5% of the study group initially presented with cysts of more than 1 cm and thus might be clinically meaningful," the researchers note.

Cyst prevalence, cyst count, and maximum cyst size increased with age.

At 5-year follow-up, 52.7% of participants showed pancreatic cysts, including 48 of 367 individuals who had no visible cysts at baseline, for a weighted 5-year incidence of 12.9% (2.6% per year).

Half the people with pancreatic cysts at baseline showed an increase in maximum cyst size at follow-up. Total cyst number increased in 35.9% of patients and was stable or declined in the rest. Only 24.1% showed an increase in both number and diameter of the cystic lesion at follow-up.

Three of 2,333 participants died of pancreatic cancer: two had not consented to MRI; the third underwent MRCP, which showed no signs of tumor or cysts.

"Against the background of remaining controversies concerning the management of incidentally detected pancreatic cysts, a restrictive therapeutic and follow-up approach can be supported," the researchers conclude. "Screening of the general population for pancreatic cystic lesions to reduce the risk of malignant transformation and to reduce the burden of pancreatic cancer cannot be recommended."

Dr. Karl K. Kwok from UCLA School of Medicine, in California, who recently reported that most deaths in patients with asymptomatic pancreatic cysts are unrelated to pancreatic cancer, told Reuters Health by email, "The high prevalence of asymptomatic pancreatic cysts (almost 50%) in this study cohort is surprising. In a sense, this reflects a general trend in modern medicine of increased medical testing, which invariably detects more findings that may not be clinically significant but can generate a substantial amount of health anxiety and unnecessary follow-up testing."

"Patients tend to assume the worst-case scenario when diagnosed with a pancreatic cyst," he said. "In reality, the vast majority of people with an incidentally discovered pancreatic cyst will never progress to a life-limiting pancreatic neoplasm."

Dr. Kwok noted that given increasing understanding of the natural history of pancreatic cysts, many resources are now available to guide general practitioners and specialists. For example, he said, "our medical group has found that a patient's underlying comorbidities greatly impact their ultimate risk of non-pancreatic-cancer death, even among those with high-risk pancreatic cysts."

Dr. James Scheiman, professor emeritus at the University of Michigan and now at the University of Virginia, in Charlottesville, has researched pancreatic cysts extensively. He told Reuters Health, "Cysts are common, particularly very small ones. Many will grow slowly, and the risk of malignancy seems very low for small, incidentally found cysts. These data support less-aggressive diagnostic and surveillance interventions for low-risk cysts in asymptomatic patients."

"Knowing which ones are neoplastic and quantifying risk of malignant potential remain a key focus of future study," Dr. Scheiman said. "A one-size-fits-all approach to the patient with pancreatic cysts is a challenge, and risk must be assessed and follow-up individualized."

Dr. Kromrey did not respond to a request for comments.

SOURCE: http://bit.ly/2jG2nLv

Gut 2017.