Background: Early diagnosis of cancer is an important challenge in general practice. Symptoms are the most common starting points.
Objective: To assess the association between symptoms presented and subsequent cancer.
Design: A cohort study of all patients seen consecutively by GPs. Prospective recording of cancer diagnosis, new cancer or new recurrence.
Setting: Two hundred and eighty-three general practice surgeries and 10 working days.
Method: During patient consultations, GPs registered seven focal symptoms and three general symptoms, commonly considered as warning signs of cancer (WSC). Follow-up 6-11 months later with registration of any subsequent diagnosis of cancer was done.
Results: Of 51 073 patients, 6321 (12.4%) had recordings of 7704 WSC. During a median follow-up period of 8 months, 263 patients were diagnosed with cancer and 59 of them with recurrence of a previously diagnosed cancer. Of the cancer patients, 106 (40%) had presented one or more WSC during a preceding consultation. Examined symptoms had likelihood ratios for cancer from 1.5 to 8.2 and positive predictive values (PPVs) from 0.8% to 3.8%. Limited to older age groups, PPVs were a little higher. General symptoms were rarely associated with cancer unless a focal symptom had been recorded as well. Multiple symptoms increased the probability of cancer.
Conclusion: 12.4% of GP patients presented with WSC. A general symptom may have cancer diagnostic value, but usually, only when it occurs along with a focal symptom. PPV of any single symptom is low, and decisions about referral require additional information.