Does Evidence Support Screening for Pancreatic Cancer?

August 14, 2019

The U.S. Preventive Services Task Force released a new review of the benefits and harms of imaging-based screening for pancreatic cancer.

The U.S. Preventive Services Task Force (USPSTF) found that imaging-based screening for pancreatic cancer can detect the malignancy in individuals with high familial risk based on a review published in JAMA.  But the evidence base for screening is still substantially limited and the organization recommends against screening in asymptomatic adults.

“Screening to detect pancreatic cancers and their potential precursor lesions could improve survival if it facilitated surgical resection for early-stage disease,” wrote authors led by Nora B. Henrikson, PhD, MPH, of the Kaiser Permanente Washington Health Research Institute in Seattle. “However, since incident pancreatic cancer is rare, with 12.6 new cases per 100,000 people in the United States in 2011-2015, identifying populations at the highest risk for pancreatic cancer is critical to developing meaningful screening or early detection programs.”

The USPSTF conducted a review of available studies of pancreatic screening published between 2002 and 2019. This included 13 prospective cohort studies involving a total of 1,317 individuals; they were conducted primarily in people considered to be at high familial risk for pancreatic adenocarcinoma.

None of the studies reported the effect of screening on pancreatic adenocarcinoma morbidity, mortality, or all-cause mortality. All of the studies did report on the diagnostic yield of screening, with a range of 0 to 75 cases per 1,000 persons. Screening methods varied, including the use of endoscopic ultrasound, MRI, and/or computed tomography. A total of 18 cases of pancreatic adenocarcinoma were detected across 1,156 adults in the studies, compared with none detected in 161 average-risk adults.

Nine of the studies reported on the procedural harms (involving 675 patients) or psychological harms (271 patients). No serious harms from screening were found. In one study, 25.5% of individuals experienced mild pain after endoscopic ultrasound screening and 6.0% of patients reported adverse events related to anesthesia. With regard to the psychological harms, distress levels remained in normal ranges throughout the studies.

“Imaging-based screening in groups at high familial risk can detect pancreatic adenocarcinoma with limited evidence of minimal harms,” the authors concluded. “However, the effect of screening on morbidity and mortality in groups at high familial risk has not been studied, and no data are available in average-risk populations.” They added that there is limited evidence to assess the benefits or harms of surgical intervention for screen-detected pancreatic adenocarcinoma.

In an accompanying editorial, Aimee L. Lucas, MD, MS, of the Icahn School of Medicine at Mount Sinai in New York, and Fay Kastrinos, MD, MPH, of Columbia University Irving Medical Center, wrote that it could be anticipated that screening in average-risk adults would produce more harm than good, given that only about 1.6% of individuals in the U.S. will develop this malignancy.

“With this relatively low prevalence, even an ideal screening test with 99% sensitivity and 99% specificity would yield 1000 false positive results if applied to 100,000 patients,” Lucas and Kastrinos wrote. “These false positive results would require subsequent diagnostic evaluation and accrue additional complications, costs, and patient distress that would cause the risks of screening to outweigh any potential benefit.”

However, certain high-risk individuals may still benefit from screening. These include individuals with two or more blood relatives affected with pancreatic cancer, and potentially those with germline mutations in ATM, BRCA1/2, CDKN2A, and several other genes.

“Accurate assessment of an asymptomatic individual’s risk for pancreatic cancer is of the utmost importance in deciding whether surveillance is warranted,” they wrote. “Further study is needed to fully define the population who should be screened and by what optimal strategy to improve outcomes and minimize harms resulting from pancreatic cancer surveillance in individuals at increased risk.”