{"entity":{"id":"paper-szpakowski-gallbladder-polyps-20-year-cohort-jama-netw-open-2020","kind":"paper","name":"Outcomes of Gallbladder Polyps and Their Association With Gallbladder Cancer in a 20-Year Cohort","aka":[],"tldr":"Following more than 600,000 people for two decades, those with gallbladder polyps on ultrasound were no more likely to get gallbladder cancer than those without, though the risk did climb for polyps of a centimetre or more; the authors question whether watching polyps finds cancer at all.","summary":"Kaiser Permanente Northern California cohort of 622,227 adults with abdominal ultrasonography between 1995 and 2014. Polyps were present in 5.8 percent of scans (35,870 people) and in 6.0 percent (22 of 365) of people later diagnosed with gallbladder cancer. Among 35,856 people with polyps, 19 (0.053 percent) developed gallbladder cancer, the same as those without polyps (316 of 586,357; 0.054 percent). The cancer rate was 11.3 per 100,000 person-years overall, 1.3 for polyps under 6 mm and 128.2 for polyps of 10 mm or more; among those followed for at least a year it was 3.6. Growth of 2 mm or more at 10 years occurred in 66.2 percent of polyps initially under 6 mm and 52.9 percent of those 6 to under 10 mm, so growth is part of natural history.","asOf":"2026-09-24","links":[{"label":"JAMA Netw Open 2020","url":"https://doi.org/10.1001/jamanetworkopen.2020.5143"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/32421183/"}],"tags":["gallbladder-evidence"],"related":[],"cancers":["gallbladder"],"sections":[],"technologies":["ultrasound"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["gallbladder-polyp","overdiagnosis","screening"],"trials":[],"people":[],"bottlenecks":["b-overdiagnosis"],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"journal":"JAMA Network Open","year":2020,"doi":"10.1001/jamanetworkopen.2020.5143","pmid":"32421183","authors":"Szpakowski JL, Tucker LY.","paperType":"observational","findings":["Gallbladder cancer in 0.053 percent of 35,856 people with polyps vs 0.054 percent of 586,357 without.","Cancer rate 11.3 per 100,000 person-years overall; 1.3 for polyps under 6 mm and 128.2 for 10 mm or more.","Growth of 2 mm or more at 10 years in 66.2 percent of polyps under 6 mm and 52.9 percent of 6 to under 10 mm polyps."],"whatItMeans":"The largest natural history study of gallbladder polyps undermines the surveillance half of the 2022 European guideline: small polyps grow as a matter of course and almost never become cancer, while size at first scan carries most of the risk.","caveats":["US insured population with low gallbladder cancer incidence; findings may not transfer to Chile or northern India.","Polyps removed at cholecystectomy during follow-up are censored, which could understate progression."],"changedPractice":false,"participants":622227},"route":"/key-papers/paper-szpakowski-gallbladder-polyps-20-year-cohort-jama-netw-open-2020/","neighbours":{"cancer":[{"id":"gallbladder","kind":"cancer","name":"Gallbladder cancer","route":"/cancers/gallbladder/"}],"technology":[{"id":"ultrasound","kind":"technology","name":"Ultrasound","route":"/technologies/ultrasound/"}],"term":[{"id":"gallbladder-polyp","kind":"term","name":"Gallbladder polyp (polypoid lesion)","route":"/terms/gallbladder-polyp/"},{"id":"overdiagnosis","kind":"term","name":"Overdiagnosis","route":"/terms/overdiagnosis/"},{"id":"screening","kind":"term","name":"Screening","route":"/terms/screening/"}],"bottleneck":[{"id":"b-overdiagnosis","kind":"bottleneck","name":"Overdiagnosis and false alarms","route":"/bottlenecks/b-overdiagnosis/"}],"roadmap":[{"id":"gallbladder-cancer-roadmap","kind":"roadmap","name":"Gallbladder cancer roadmap: from a chance finding at gallstone surgery to a disease with its own trials","route":"/roadmaps/gallbladder-cancer-roadmap/"}],"idea":[{"id":"idea-gbc-risk-targeted-ultrasound-in-high-incidence-regions","kind":"idea","name":"Risk-targeted ultrasound screening in high-incidence regions, tested against usual care","route":"/ideas/idea-gbc-risk-targeted-ultrasound-in-high-incidence-regions/"}]}}