title: Urgent referral for suspected CNS cancer: which clinical features are associated with a positive predictive value of 3 % or more?
abstract: BACKGROUND
  Urgent referral for suspected central nervous system (CNS) cancer is recommended, but little analysis of the referral criteria diagnostic performance has been conducted. New 2015 NICE guidance recommends direct brain imaging for patients with symptoms with positive predictive values (PPV) of 3 %, but further guidance is needed.
  
  
  METHODS
  A 12-month retrospective evaluation of 393 patients referred under previous 2005 NICE 2-week rule criteria was conducted. Analysis was based on the three groups of symptoms forming the referral criteria, (1) CNS symptoms, (2) recent onset headaches, (3) rapidly progressive subacute focal deficit/cognitive/behavioural/personality change. Comparison was made with neuroimaging findings.
  
  
  RESULTS
  Twelve (3.1 %) of 383 patients who attended clinic had CNS cancer suggesting the combination of clinical judgement and application of 2005 criteria matched the 2015 guideline's PPV threshold. PPVs for the three groups of symptoms were (1) 4.1 % (95 % CIs 2.0 to 7.4 %), (2) 1.2 % (0.1 to 4.3 %) and (3) 3.7 % (0.1 to 19.0 %). Sensitivities were (1) 83.3 % (95 % CIs 51.6 to 97.9 %), (2) 16.7 % (2.1 to 48.4 %), and (3) 8.3 % (0.2 to 38.5 %); specificities were (1) 37.2 % (32.3 to 42.3 %), (2) 55.5 % (50.3 to 60.7 %) and (3) 93.0 % (89.9 to 95.4 %). Of 288 patients who underwent neuroimaging, 59 (20.5 %) had incidental findings, most commonly cerebrovascular disease.
  
  
  CONCLUSIONS
  The 2015 guidance is less prescriptive than previous criteria making clinical judgement more important. CNS symptoms had greatest sensitivity, while PPVs for CNS symptoms and rapidly progressive subacute deficit/cognitive/behavioural/personality change were closest to 3 %. Recent onset headaches had the lowest sensitivity and PPV.
authors: Department of Neurology, Royal Preston Hospital, Sharoe Green Lane, Fulwood, Preston, PR2 9HT, UK. hasanmohammad@doctors.org.uk.|Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK. hasanmohammad@doctors.org.uk.
authors: Hasan Raza
authors: HR
authors: Mohammad
authors: Department of Neurology, Royal Preston Hospital, Sharoe Green Lane, Fulwood, Preston, PR2 9HT, UK.
authors: Jeremy
authors: J
authors: Boardman
authors: College of Health and Wellbeing, University of Central Lancashire, Fylde Road, Preston, PR1 2HE, UK.
authors: Laura
authors: L
authors: Howell
authors: Department of Neurology, Royal Preston Hospital, Sharoe Green Lane, Fulwood, Preston, PR2 9HT, UK.
authors: Roger J
authors: RJ
authors: Mills
authors: Department of Neurology, Royal Preston Hospital, Sharoe Green Lane, Fulwood, Preston, PR2 9HT, UK.|Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
authors: Hedley C A
authors: HC
authors: Emsley
mesh_terms: D016543:Central Nervous System Neoplasms / Q000175:diagnosis*; D000066491:Clinical Decision-Making; D019983:Guideline Adherence; D006801:Humans; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D012017:Referral and Consultation; D012189:Retrospective Studies; D013997:Time Factors
keywords: CNS cancer; NICE guidance; Positive predictive value; Retrospective study; Two-week referral