Thomas Falasca, physician and author of Physician’s Guide to Better Medical Decision Making: Critical Thinking in Medicine
The fearsome nature of pancreatic cancer makes screening and early treatment of this aggressive malignancy an attractive concept. Such screening and early treatment is the subject of a recent editorial in JAMA Surgery (published online August 6, 2019). While the article is optimistic for the future of screening and early treatment of pancreatic cancer, it is less sanguine about the present situation. Importantly, its reservations regarding the present provide special insight into screening’s limitations.
The article relates that the United States Preventive Services Task Force (USPSTF) “found no evidence that screening for pancreatic cancer improves disease-specific survival.”
One screening issue is that even a highly specific test will generate a number of false positives dependent on the number of people screened. If the number screened is large and the disease incidence is not, the number of false positives can be significant. The problem of false positives can be ameliorated if screening is confined to populations with a high baseline incidence of the disease. False positives are harmful when subsequent treatment involves chemotherapy and aggressive surgery.
These considerations could change if the disease incidence increases or if morbidity and mortality of the interventions decreases.
Another screening problem is that the rapid progression of pancreatic cancer makes the window of opportunity for screening very narrow. Patients might need to be screened repeatedly at very short intervals. While slow progression velocity makes colon cancer screening attractive, rapid progression velocity may make pancreatic cancer screening unattractive.
These are important issues regarding the screening of otherwise normal people and it is fortunate that the issue of pancreatic screening has illuminated them.
