The risk of pancreatic cancer in symptomatic patients in primary care: a large case-control study using electronic records

Abstract

BACKGROUND: Over 8000 new pancreatic cancers are diagnosed annually in the UK; most at an advanced stage, with only 3% 5-year survival. We aimed to identify and quantify the risk of pancreatic cancer for features in primary care. METHODS: A case-control study using electronic primary care records identified and quantified the features of pancreatic cancer. Cases, aged ≥40 in the General Practice Research Database, UK, with primary pancreatic cancer were matched with controls on age, sex and practice. Putative features of pancreatic cancer were identified in the year before diagnosis. Odds ratios (OR) were calculated for features of cancer using conditional logistic regression. Positive predictive values (PPV) were calculated for consulting patients. RESULTS: In all, 3635 cases and 16,459 controls were studied. Nine features were associated with pancreatic cancer (all P<0.001 except for back pain, P=0.004); jaundice, OR 1000 (95% confidence interval (CI) 4,302,500); abdominal pain, 5 (4.4, 5.6); nausea/vomiting, 4.5 (3.5, 5.7); back pain, 1.4 (1.1, 1.7); constipation, 2.2 (1.7, 2.8); diarrhoea, 1.9 (1.5, 2.5); weight loss, 15 (11, 22); malaise, 2.4 (1.6, 3.5); new-onset diabetes 2.1 (1.7, 2.5). Positive predictive values for patients aged ≥60 were <1%, apart from jaundice at 22% (95% CI 14, 52), though several pairs of symptoms had PPVs >1%. CONCLUSION: Most previously reported symptoms of pancreatic cancer were also relevant in primary care. Although predictive values were small - apart from jaundice - they provide a basis for selection of patients for investigation, especially with multiple symptoms.