Cancer risk in patients with recurrent or persistent symptoms: a systematic review

Most cancers are diagnosed following symptomatic presentation. European guidelines supporting general practitioner cancer referrals largely focus on 'alarm' symptoms. However, about half of cancer patients do not present with alarm symptoms. Understanding cancer risk in these patients can help identify those who might need further investigations. This systematic review quantified positive predictive values (PPVs) of recurrent and persistent symptoms for cancer. Evidence from 21 studies reporting on nearly 200,000 patients, identified PPVs for 33 recurrent and 22 persistent symptoms. 'Persistent' and 'recurrent' symptoms were inconsistently defined. In addition to recurrent 'alarm' symptoms, recurrent abdominal distension, abdominal pain and rectal bleeding had PPVs above 3%, the existing English referral threshold, in patients younger than currently recommended for specialist investigation. Persistent symptoms were predominately studied in referred populations. Clearer definitions of recurrence and persistence, and prospective validation of cancer risk for patients with non-alarm symptoms across all age groups are needed to refine guidance and support early cancer diagnosis.