shows a new study published in Gastroenterology.
While other studies have shown potential benefit in screening high-risk individuals, “a concern is that in absence of sufficiently large control groups with unscreened controls,” the outcomes may be influenced by lead-time bias. The current study is the first to address that important limitation.
The study, which was led by Derk C.F. Klatte, MD, of the department of gastroenterology and hepatology at Leiden University Medical Center, the Netherlands, included 43,762 patients from the Netherlands Cancer Registry who were diagnosed with PDAC between January 2000 and December 2020. Using a 1:5 ratio, researchers matched 31 patients who were diagnosed in the pancreatic cancer surveillance cohort against 155 patients in the non-surveillance group.
Leiden University Medical Center
Dr. Derk C.F. Klatte
“We show that surveillance for PDAC in high-risk individuals results in significant earlier detection, increased resectability, and improved survival as compared with average-risk individuals diagnosed with PDAC not under surveillance. This reaffirms that pancreatic surveillance for certain in high-risk individuals is beneficial and could have a meaningful impact on disease course,” the authors wrote.
PDAC has the worst outcomes all cancers and is on pace to become the second-leading cause of cancer-related mortality. By the time a tumor is detected, it is usually unresectable or has developed distant metastases. In principle, early detection could improve outcomes, but there is no test that is adequate for population-wide screening. Surveillance must therefore concentrate on individuals deemed to be at heightened risk. Prospective studies have shown a benefit of pancreatic cancer screening in patients who are at high-risk. Such studies may be misleading, however, due to the potential for lead-time bias. This can occur when a condition is detected at an earlier time than it would have been identified based on clinical signs, as usually occurs in nonscreened populations, and this asymptomatic lag time between diagnosis and initial symptoms does not get incorporated into a survival analysis. The result can be an artificially longer survival time following diagnosis in the screened population.
Guidelines from the International Cancer of the Pancreas Screening (CAPS) consortium, the American Society for Gastrointestinal Endoscopy, and American Society of Clinical Oncology recommend surveillance in high-risk cases.
In this study, researchers conducted a propensity score matched cohort analysis of patients from the general population with primary PDAC who were diagnosed outside of a screening program, with carriers of a germline CDKN2A/p16 mutation who were diagnosed after surveillance.
The surveillance group received a stage 1 diagnosis in 38.7% of cases, versus 5.8% of those outside of surveillance (odds ratio [OR], 0.09; 95% confidence interval [CI], 0.04-0.19). Surgical resection occurred in 71.0% of surveillance patients, versus 18.7% of non-surveillance patients (OR, 10.62; 95% CI, 4.56-26.63), and stage 4 diagnoses were much more common in the nonsurveillance population (61.3% versus 9.7%). Among the patients who did not undergo surveillance, 61.3% were diagnosed with stage 4 disease compared with 9.7% of those in the surveillance group.
The 5-year survival rate (unadjusted for lead-time) in the surveillance group was 32.4% and 4.3% in the nonsurveillance group. The median overall survival was 26.8 months in the surveillance group compared with 5.2 months in the nonsurveillance group, (hazard ratio, 0.22; 95% CI, 0.14-0.36). The mortality rate per 100 person-years was 114.5 (95% CI, 96.2–135.3) in nonsurveillance patients and 21.9 (95% CI, 13.4–33.8) in surveillance patients.
Despite the apparent benefit of screening, there is room for improvement. “Although the outcomes presented here are encouraging and endorse our earlier findings, a significant proportion of surveillance patients (61%) still had poor outcomes because of diagnosis in a late stage (T2–4N0M0 and nodal or distant metastatic PDAC), with a 5-year survival of 16%,” the authors wrote.
The study received no funding and the authors declared no conflicts.
