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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] Ç‚

 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] Ç‚

 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. Ç‚ 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