Purpose: Family physicians (FPs) have to recognize alarm symptoms and estimate the probability of cancer to manage these symptoms correctly. Mostly, patients start the consultation with a spontaneous statement on why they visit the doctor. This is also called the reason for encounter (RFE). It precedes the interaction and interpretation by FPs and patients. The aim of this study is to investigate the predictive value of alarm symptoms as the RFE for diagnosing cancer in primary care.Design and setting: Retrospective cohort study in a Dutch practice-based research network (Family Medicine Network).Method: We analyzed all patients >45 years of age listed in the practice-based research network, FaMe-net, in the period 1995 to 2014 (118.219 patient years). We focused on a selection of alarm symptoms as defined by the Dutch Cancer Society and Cancer Research UK. We calculated the positive predictive value (PPV) of alarm symptoms, spontaneously mentioned in the beginning of the consultation by the patient (RFE), for diagnosing cancer.Results: The highest PPVs were found for patients spontaneously mentioning a breast lump (PPV 14.8%), postmenopausal bleeding (PPV 3.9%), hemoptysis (PPV 2.7%), rectal bleeding (PPV 2.6%), hematuria (PPV 2.2%) and change in bowel movements (PPV 1.8%).Conclusion: Patients think about going to their physician and think about their first uttered statements during the consultation. In the case of cancer, the diagnostic workup during the consultation on alarm symptoms will add to the predictive value of these reasons for encounter. However, it is important to realize that the statement made by the patient entering the consultation room has a significant predictive value in itself. (J Am Board Fam Med 2017;30:806 -812.)