{"entity":{"id":"paper-fahrmann-ca19-9-lead-time-gastroenterology-2021","kind":"paper","name":"Lead-Time Trajectory of CA19-9 as an Anchor Marker for Pancreatic Cancer Early Detection","aka":[],"tldr":"A 2021 study of stored blood from a US screening trial showing that CA 19-9 starts rising about two years before pancreatic cancer is diagnosed and catches half of early-stage cases in the final six months, so it can anchor a multi-marker early detection test.","summary":"Fahrmann and colleagues measured CA 19-9 in blinded sera from 175 subjects collected up to five years before a pancreatic cancer diagnosis and 875 matched controls from the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, and in independent sets of 129 resectable cases and 275 controls (100 healthy, 50 chronic pancreatitis, 125 non-cancerous cysts). Levels rose exponentially from two years before diagnosis; sensitivity reached 60 percent at 99 percent specificity within 0 to 6 months of diagnosis for all cases and 50 percent for early-stage cases. Resectable cases were distinguished from healthy controls at 64 percent sensitivity, from chronic pancreatitis at 46 percent and from cysts at 30 percent, all at 99 percent specificity. Adding LRG1 and TIMP1 raised sensitivity by 13.2 percentage points (P = 0.031) for cases below the CA 19-9 cutoff diagnosed within a year.","asOf":"2026-09-24","links":[{"label":"Gastroenterology 2021","url":"https://doi.org/10.1053/j.gastro.2020.11.052"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/33333055/"}],"tags":["pancreatic-evidence"],"related":["paper-tempero-ca19-9-lewis-antigens-cancer-res-1987","paper-sharma-endpac-model-new-onset-diabetes-gastroenterology-2018","early-detection-roadmap"],"cancers":["pancreatic"],"sections":[],"technologies":["liquid-biopsy","mced","proteomics"],"targets":[],"drugs":[],"companies":[],"institutions":["md-anderson"],"pathways":[],"terms":["ca19-9","tumour-markers","ppv"],"trials":[],"people":["anirban-maitra"],"bottlenecks":["b-early-detection","b-biomarker-validation"],"keyPapers":[],"journals":["gastroenterology"],"dependsOn":[],"notes":[],"journal":"Gastroenterology","year":2021,"doi":"10.1053/j.gastro.2020.11.052","pmid":"33333055","authors":"Fahrmann JF, Schmidt CM, Mao X, et al.","paperType":"translational","findings":["175 pre-diagnostic cases and 875 controls from PLCO; CA 19-9 rose exponentially from two years before diagnosis.","Sensitivity 60 percent at 99 percent specificity within six months of diagnosis, 50 percent for early-stage cases.","LRG1 and TIMP1 added 13.2 percentage points of sensitivity below the CA 19-9 cutoff."],"whatItMeans":"Fixes the window in which a blood test could plausibly work and shows why CA 19-9 alone is not enough: half of early cases are missed even at diagnosis, and Lewis-negative patients are missed entirely.","caveats":["Retrospective, nested in a screening trial that did not screen for pancreatic cancer; performance in a prospective new-onset diabetes cohort is unknown.","99 percent specificity still yields many false positives in an average-risk population."],"participants":1050},"route":"/key-papers/paper-fahrmann-ca19-9-lead-time-gastroenterology-2021/","neighbours":{"paper":[{"id":"paper-sharma-endpac-model-new-onset-diabetes-gastroenterology-2018","kind":"paper","name":"Model to Determine Risk of Pancreatic Cancer in Patients With New-Onset Diabetes","route":"/key-papers/paper-sharma-endpac-model-new-onset-diabetes-gastroenterology-2018/"},{"id":"paper-tempero-ca19-9-lewis-antigens-cancer-res-1987","kind":"paper","name":"Relationship of carbohydrate antigen 19-9 and Lewis antigens in pancreatic cancer","route":"/key-papers/paper-tempero-ca19-9-lewis-antigens-cancer-res-1987/"}],"roadmap":[{"id":"early-detection-roadmap","kind":"roadmap","name":"Early detection roadmap: organ screening → blood tests for many cancers","route":"/roadmaps/early-detection-roadmap/"},{"id":"pancreatic-roadmap","kind":"roadmap","name":"Pancreatic cancer roadmap: from Whipple's operation to gemcitabine, FOLFIRINOX, adjuvant chemotherapy, PARP inhibition, KRAS inhibition, vaccines and the surveillance question","route":"/roadmaps/pancreatic-roadmap/"}],"cancer":[{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"}],"technology":[{"id":"liquid-biopsy","kind":"technology","name":"Liquid biopsy (ctDNA)","route":"/technologies/liquid-biopsy/"},{"id":"mced","kind":"technology","name":"Multi-cancer early detection (MCED)","route":"/technologies/mced/"},{"id":"proteomics","kind":"technology","name":"Proteomics & phosphoproteomics","route":"/technologies/proteomics/"}],"institution":[{"id":"md-anderson","kind":"institution","name":"MD Anderson Cancer Center","route":"/institutions/md-anderson/"}],"term":[{"id":"ca19-9","kind":"term","name":"CA 19-9","route":"/terms/ca19-9/"},{"id":"ppv","kind":"term","name":"Positive predictive value (PPV)","route":"/terms/ppv/"},{"id":"tumour-markers","kind":"term","name":"Tumour markers (CEA, LDH, chromogranin, thyroglobulin)","route":"/terms/tumour-markers/"}],"person":[{"id":"anirban-maitra","kind":"person","name":"Anirban Maitra","route":"/people/anirban-maitra/"}],"bottleneck":[{"id":"b-biomarker-validation","kind":"bottleneck","name":"Biomarkers are not validated or standardised","route":"/bottlenecks/b-biomarker-validation/"},{"id":"b-early-detection","kind":"bottleneck","name":"The hardest cancers are found late","route":"/bottlenecks/b-early-detection/"}],"journal":[{"id":"gastroenterology","kind":"journal","name":"Gastroenterology","route":"/journals/gastroenterology/"}],"idea":[{"id":"idea-pdac-new-onset-diabetes-risk-score-pathway","kind":"idea","name":"Run the ENDPAC score on every new diabetes diagnosis after 50 and scan the high scorers","route":"/ideas/idea-pdac-new-onset-diabetes-risk-score-pathway/"}]}}