Regional cancer genetics services in the UK base many of their risk assessments on the careful evaluation of a family history of disease. The pathological details of cancers in relatives can help refine this risk assessment and alter subsequent management. By analysing a variety of medical records, we surveyed how often a reported family history was discrepant from that recorded in the records, and how often this impacted on surveillance recommendations. Our survey analysed pathology confirmation and risk assessment in families over a 7-month period of referrals. 839 cancers were reported and 476 were independently confirmed. The accuracy of a reported family history differed depending on the reported site of a cancer and on the degree of relationship to the patient. Whilst the majority of reported cancers (84%) were confirmed, a change in risk assessment through pathology confirmation resulted in altered management in 20% of all referrals.