Although many of the symptoms of cancer are well documented, they are also very common in benign conditions. It is therefore difficult for a General Practitioner (GP) to identify which patients, presenting with symptoms, warrant further investigation and the level of cancer risk these features represent. Two case-control studies examined all cases of pancreatic (3,647) and oesophagogastric (7.657) cancers arising in the Clinical Practice Research Datalink (CPRD) (previously known as the General Practice Research Database (GPRD» United Kingdom (UK) from 2000-2009. Each case was matched with up to five age, sex and practice matched controls, randomly generated by CPRD. The entire primary care records for one year before the diagnosis of the cancer for all cases and controls were searched to identity features from medical text books, literature, cancer charities and websites. Conditional logistic regression analysis reported all features independently associated with each cancer. Likelihood ratios (LRs) and positive predictive values (PPVs) for these variables were calculated for patients consulting in primary care. Nine features were independently associated with pancreatic cancer. PPVs of individual symptoms and pairs of symptoms were calculated to identify patients with apparently low risk symptoms, but whose total risk warranted further investigation. 1.n the oesophago-gastric study, sixteen features were independently associated with cancer, including a relatively new finding of an association with thrombocytosis which has not been previously reported in association with oesophago-gastric cancer. Although the results largely support national referral guidelines for suspected cancer, they provide a robust evidence base for many of the recommendations. They should also inform commissioning policy for upper gastro-intestinal (GI) endoscopy and help in the selection of patients for endoscopic investigation if the UK's poor survival record is to be improved.