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Table 1 Health State Transition Model Parameters

From: Cost-effectiveness analysis of anal cancer screening in women with cervical neoplasia in British Columbia, Canada

Parameter Point Estimate SE Distribution used in PSA Source
Transition probability
 AIN Status     
  No AIN 88 % 3.2 % Dirichlet Santoso, 2010 [13]
  AIN1 11 % 3.1 %   
  AIN2+ 1 % 1.0 %   
 Screening utility of Pap     Santoso, 2010 [13]
  Sensitivity 40 % 2.6 % Normal  
  Specificity 94 % 2.6 % Beta  
 Resection failure rate 10 % 1.0 % Normal Abbasakoor, 2005
 AIN1 lesion recurrence rate 25 % 3.2 % Normal  
 AIN2+ lesion recurrence rate 25 % 3.1 % Normal  
 Pre-cancer survival     Palefsky, 1998 [35]
  Development of new AIN1 3.5 % 1.3 % Beta  
  Remission of AIN1 3.5 % 1.5 % Beta  
  Progression from AIN1 to AIN2+ 20 % 2.0 % Normal  
 Development of cancer     Adapted from Malachek 2012 [36] for HIV- MSM
  AIN2+ to Early-stage ASCC 0.012 % 0.001 % Normal  
  AIN2+ to Late-stage ASCC 0.006 % 0.001 % Normal  
  AIN2+ to Metastatic ASCC 0.002 % 0.0004 % Normal  
 Cancer survival     AJCC 2010 [2, 37]
Uronis 2007
  Progressive disease following early-stage treatment 20 % 2.5 % Normal  
  Progressive disease following late-stage treatment 50 % 4.1 % Normal  
  Recurrence 15 % 1.2 % Normal  
  Progression to metastatic disease 50 % 2.2 % Normal  
  Death from progressive disease 80 % 4.1 % Beta  
  Death from metastatic disease 100 % 0.5 % Beta  
Health utilities˧
 No AIN 0.98 0.028 Beta Insinga, 2007 [38] ǂ
 Undetected AIN1 0.98 0.024 Beta Insinga, 2007 [38]
 Undetected AIN2+ 0·98 0.024 Beta Insinga, 2007 [38]
 Screen-detected lesion, resection 0·87 0.085 Beta Insinga, 2007 [38]
 Successfully-managed ASCC     
  First year 0·57 0.020 Normal Conway, 2012 [39]
  Subsequent years 0·82 0.068 Beta Melnikow, 2010 [40] ǂ
 Progressive ASCC 0.57 0.020 Normal Conway, 2012 [39]
 Metastatic ASCC 0.57 0.020 Normal Conway, 2012 [39]
Costs
 Cost of anal swab $6 $6 Gamma BC Cancer Agency
 Cost of anoscopy $7.55 $7.55 Gamma BC Ministry of Health
 Cost of resecting an anal lesion $73.96 $73.96 Gamma BC Ministry of Health
 Cost of a screening appointment $30.15 $30.15 Gamma BC Ministry of Health
 Cost of treating ASCC $11,625 $11,625 Gamma BCCA Ŧ
 Cost of cancer follow-up appointment $464 $46 Gamma Tsoi, 2010 [27]
 Cost of managing progressive ASCC $18,377 $3634 Normal Czoski-Murray, 2010 [19]
 Cost of managing metastatic disease $36,612 $7288 Normal Tsoi, 2010 [27]
  1. ASCC anal squamous cell carcinoma, AIN anal interepithelial neoplasia, AIN1/AIN2+ low-grade/high-grade AIN, CIN cervical interepithelial neoplasia
  2. ˧ N.B. Utilities are assumed to be constant over the value of a cycle length (i.e., 1 year)
  3. ǂ N.B. Because anal screening utility weights were not available, utilities were assumed to be similar to values found in women screened and treated for cervical lesions/cancers
  4. Ŧ Based on cost of BCCA Chemoradiation protocols GIPART, GICART [26] – drug and administration costing data provided by BCCA Systemic Therapy Program