title: If your lump is bigger than a golf ball and growing, think Sarcoma.
abstract: OBJECTIVE
  Only 1 in 100 of primary care consultations regarding new soft tissue lumps (STL) are malignant and are susceptible to a delay in diagnosis. We aimed to generate a Bayesian Belief Network to estimate the likelihood of malignancy in patients to facilitate the initial evaluation of a STL and improve timing and quality of referrals to specialist treatment centres.
  
  
  METHODS
  We evaluated all patients referred with a new STL between 1996 and 2007. Variables investigated focused on patient factors, symptoms and STL characteristics. Relevant data was extracted and coded for statistical analysis.
  
  
  RESULTS
  3018 patients with a STL were assessed, of which 1563 (52%) were benign and 1455 (48%) malignant. The features most conditionally associated with the outcome of interest (Benign or Malignant) are referred to as first-degree associates, and are increasing size, age, size of the lump, and duration of symptoms, in that order. On cross validation, this model demonstrated an AUC of 0.77 (95%C.I. 0.75-0.79).
  
  
  CONCLUSIONS
  For the first time, we have described the hierarchal relationship between factors and created an aide memoire, larger than a golf ball and growing, to trigger referral to tertiary tumor units. Importantly, we found pain to be a poor discriminatory factor. We hope our findings will lead to greater awareness and earlier diagnosis of STL.
authors.affiliation: Bone Tumor Service, The Royal Orthopaedic Hospital, Bristol Road South, Birmingham B31 2AP, United Kingdom. Electronic address: rajpalnandra@nhs.net.
authors.forename: R
authors.initials: R
authors.lastname: Nandra
authors.affiliation: Section of Orthopaedics and Sports Medicine, Department of Molecular Medicine and Surgery, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden. Electronic address: jonathan.forsberg@ki.se.
authors.forename: J
authors.initials: J
authors.lastname: Forsberg
authors.affiliation: Bone Tumor Service, The Royal Orthopaedic Hospital, Bristol Road South, Birmingham B31 2AP, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Grimer
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D001499:Bayes Theorem; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D010146:Pain / Q000209:etiology; D012017:Referral and Consultation; D012189:Retrospective Studies; D012509:Sarcoma / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000150:complications / Q000175:diagnosis / Q000473:pathology*; D062606:Tertiary Care Centers; D013997:Time Factors; D047368:Tumor Burden
keywords: Bayesian belief network; Golf ball; Nomogram; Sarcoma; Soft tissue lump