Background General practitioners (GPs) use gut feelings to diagnose cancer in an early stage, but little is known about its impact.

Method Prospective cohort study of patients in 44 general practices throughout the Netherlands, from January 2010 until December 2013. GPs completed a questionnaire regarding gut feelings, patient and GP characteristics, if they noticed a cancer-related gut feeling during patient consultation. Follow-up questionnaires were sent 3 months later requesting information about the patient's diagnosis. χ², univariate and multivariate logistic regression and multilevel analyses were performed.

Results A gut feeling (N=366) is most often triggered by weight loss (24%, N=85) and rare GP visits (22%, N=76), but all triggers were not predictive of cancer in a multivariate analysis. Most GPs (95%) acted immediately on the gut feeling, either referring to a specialist or by performing additional medical tests. The average positive predictive value of cancer-related gut feeling was 35%, and it increased with 2% for every year a patient becomes older, and with 3% for every year a GP becomes older.

Conclusions GP's gut feeling for cancer proves to be a useful tool in diagnosing cancer and its relative high predicting value increases if the GP is older or more experienced and when the patient is older. How can younger GPs be trained to increase the predictive value of their gut feeling?