Table 1. Probabilities for decision
tree
|
Name of branch |
Definition
of branch (a) Watchful Following Option |
Probability: variable and value |
Source |
|
Dysp regresses from CIN 1 |
Dysplasia regresses from CIN 1/watchful follow |
preggfol = .57 |
Ostor, 1993 |
|
Dysp persists as CIN 1 |
Dysplasia persists as CIN 1/watchful follow |
ppergfol = proporpersist * (1 - preggfol) = .74*(1- 57) = .318 |
Ostor, 1993 |
|
Dysp progresses to CIN 2 |
Dysplasia progresses to CIN 2/watchful follow |
pCIN2 = propCIN2* (1-preggfol-ppergfol) = .5 * (1-.57-.318) = .056 |
Authors' judgment |
|
Dysp progresses to CIN 3 |
Dysplasia progresses to CIN 2/watchful follow |
# = .056 |
Nasiell, 1986, Ostor, 1993, Authors' judgment |
|
Dis req invas proc (1) |
Persisting dysplasia requires invasive procedure/persists (Invasive Procedure Situation 1) |
pCIN1reqinvproc = .35*pdisreqinvas = .35 * .2 = .07 |
Authors' judgment |
|
Does not req invas proc |
Persisting dysplasia does not require invasive procedure/persists |
# = .93 |
# |
|
1st Cryo g dys pers |
Doctor chooses cryotherapy/dysplasia persists and does not require invasive procedure |
pcryogpersist = pcryovsinvas = .75 |
Authors' judgment |
|
Dr. choose invas proc (4) |
Doctor chooses invasive procedure/dysplasia persists and does not require invasive procedure (Invasive Procedure Situation 4) |
# = .25 |
# |
|
Cure with 1 cryo g pers |
Cryotherapy cures dysplasia/dysplasia persists and doctor chooses cryotherapy |
pcurg1cryopers = .98*pcurgcryo = .98 * .95 = .931 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, Authors' judgment |
|
Not cured |
Cryotherapy does not cure persisting dysplasia |
# = .069 |
# |
|
Possible to view |
It is possible to view cervix with colposcope /cryotherapy did not cure persisting dysplasia |
pviewg1cryfail = pviewgimcryfail = .70 |
Jobson, 1984, Einerth, 1988, Ferenczy, 1985 |
|
Not viewable, diagnosis requires invas proc (11) |
It is not possible to view cervix with colposcope /cryotherapy did not cure persisting dysplasia (Invasive Procedure Situation 11) |
# = .30 |
# |
|
Dis req invas proc (2) |
Disease requires invasive procedure /cryotherapy did not cure persisting dysplasia, and cervix can be viewed adequately with colposcopy (Invasive Procedure Situation 2) |
pdreqinvg1crgper = 1 - .81 * (1 -
pdisreqinvas) = 1 - .81 * (1 - .2) = .352 |
Authors' judgment |
|
Inv proc not required |
Disease does not require invasive procedure /cryotherapy did not cure persisting dysplasia, and cervix can be viewed |
# = .648 |
# |
|
Doc choose cryo |
Doctor chooses to repeat cryotherapy /first cryotherapy failed on persisting dysplasia, and invasive procedure is not required |
p2cryg1crfaigper = .20 * pcryovsinvas = .20 * .75 = .15 |
Authors' judgment |
|
Dr. choose inv proc (3) |
Doctor chooses invasive procedure /first cryotherapy failed on persisting dysplasia, and invasive procedure is not required (Invasive Procedure Situation 3) |
# = .85 |
# |
|
Cure g 2 cryos |
The second cryotherapy cures the dysplasia that had been treated with cryotherapy after persisting |
pcurg2cryo = .95 * pcurgcryo = .95 * .95 = .903 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, Authors' judgment |
|
Cryo ineffective (9) |
The second cryotherapy fails to cure the dysplasia that had been treated with cryotherapy after persisting (Invasive Procedure Situation 9) |
# = .097 |
# |
|
Dis req invas proc (51) |
Progressing dysplasia requires invasive procedure/ progresses to CIN 2 (Invasive Procedure Situation 51) |
pCIN2reqinvproc = pdisreqinvas = .20 |
Authors' judgment |
|
Does not req inv proc |
Progressing dysplasia does not require invasive procedure /progresses to CIN 2 |
# = .80 |
# |
|
1st Cryo g dys prog |
Doctor chooses cryotherapy /dysplasia progresses to CIN 2 and does not require invasive procedure |
pcryogCIN2 = .8 * pcryovsinvas = .8 * .75 = .60 |
Authors' judgment |
|
Dr. chooses invas proc (121) |
Doctor chooses invasive procedure /dysplasia progresses to CIN 2 and does not require invasive procedure (Invasive Procedure Situation 121) |
# = .40 |
# |
|
Cure with 1 cryo g prog |
Cryotherapy cures dysplasia/dysplasia progresses to CIN 2 and doctor chooses cryotherapy |
pcurg1cryoprog = .95 * pcurgcryo = .95 * .95 = .903 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, Authors' judgment |
|
Not cured |
Cryotherapy does not cure dysplasia/dysplasia progresses to CIN 2 and doctor chooses cryotherapy |
# = .097 |
# |
|
Possible to view |
It is possible to view cervix with colposcope /cryotherapy did not cure dysplasia that progressed to CIN 2 |
pviewg1cryfail = pviewgimcryfail = .70 |
Jobson, 1984, Einerth, 1988, Ferenczy, 1985 |
|
Not viewable, diagnosis requires invas proc (101) |
It is not possible to view cervix with colposcope /cryotherapy did not cure dysplasia that progressed to CIN 2 (Invasive Procedure Situation 101) |
# = .30 |
# |
|
Dis req invas proc (61) |
Disease requires invasive procedure /cryotherapy did not cure dysplasia that progressed to CIN 2, and cervix can be viewed adequately with colposcopy (Invasive Procedure Situation 61) |
pdreqinvg1crgpro = 1-.525*(1-pdisreqinvas) = 1-.525*(1-.20) = .58 |
Authors' judgment |
|
Inv proc not required |
Disease does not require invasive procedure /cryotherapy did not cure dysplasia that progressed to CIN 2, and cervix can be viewed |
# = .42 |
# |
|
Doc choose cryo |
Doctor chooses to repeat cryotherapy /first cryotherapy failed on dysplasia that progressed to CIN 2, and invasive procedure is not required |
p2cryg1crfaigpro = .1333*pcryovsinvas = .1333 * .75 = .10 |
Authors' judgment |
|
Dr. chooses invas proc (71) |
Doctor chooses invasive procedure /first cryotherapy failed on dysplasia that progressed to CIN 2, and invasive procedure is not required (Invasive Procedure Situation 71) |
# = .90 |
# |
|
Cure g 2 cryos |
The second cryotherapy cures the dysplasia that had been treated with cryotherapy after progressing to CIN 2 |
pcurg2cryogprog = .85 * pcurgcryo = .85 * .95 = .808 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, Authors' judgment |
|
Cryo ineffective (81) |
The second cryotherapy fails to cure the dysplasia that had been treated with cryotherapy after progressing to CIN 2 (Invasive Procedure Situation 81) |
# = .192 |
# |
|
Dis req invas proc (52) |
Progressing dysplasia requires invasive procedure/ progresses to CIN 3 (Invasive Procedure Situation 52) |
pcin3reqinvproc = 1.0 |
Authors' judgment |
|
|
Immediate Cryotherapy Option |
|
|
|
Cure with immed cryotherapy |
Immediate cryotherapy cures dysplasia |
pcurgimcryo = pcurgcryo = .95 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, |
|
Not cured |
Immediate cryotherapy does not cure dysplasia |
# = .05 |
# |
|
Possible to view |
It is possible to view cervix with colposcope /immediate cryotherapy did not cure dysplasia |
pviewgimcryfail = .70 |
Jobson, 1984, Einerth, 1988, Ferenczy, 1985 |
|
Not viewable, diagnosis requires invas proc (13) |
It is not possible to view cervix with colposcope /immediate cryotherapy did not cure dysplasia (Invasive Procedure Situation 13) |
# = .30 |
# |
|
Dis req invas proc (14) |
Disease requires invasive procedure /immediate cryotherapy did not cure dysplasia, and cervix can be viewed adequately with colposcopy (Invasive Procedure Situation 14) |
pdreqinvgimcrfai = 1 - .875 * (1 -
pdisreqinvas) = 1-.875*(1-.2) = .30 |
Authors' judgment |
|
Inv proc not required |
Disease does not require invasive procedure /immediate cryotherapy did not cure dysplasia, and cervix can be viewed |
# = .70 |
# |
|
Doc choose cryo |
Doctor chooses to repeat cryotherapy /immediate cryotherapy did not cure dysplasia, and cervix can be viewed |
p2crygimcryfail = .3333*pcryovsinvas .3333 * .75 = .25 |
Authors' judgment |
|
Dr. chooses invas proc (15) |
Doctor chooses invasive procedure /immediate cryotherapy failed, and invasive procedure is not required (Invasive Procedure Situation 15) |
# = .75 |
# |
|
Cure g 2 cryos |
The second cryotherapy cures the dysplasia that had been immediately treated with cryotherapy |
pcurg2cryo = .95 * pcurgcryo = .95 * .95 = .903 |
Benedet, 1987, Ostergard, 1980, Creaseman, 1981, Authors' judgment |
|
Cryo ineffective, so do invasive proc (16) |
The second cryotherapy fails to cure the dysplasia that had been treated immediately with cryotherapy (Invasive Procedure Situation 16) |
# = .097 |
# |
a The symbol "/" in the
definition of the branch indicates the previous branch, and can be read as
"given".
# indicates this probability is the complement of
probabilities immediately higher in the table.
Return to text at
http://www.fammed.ouhsc.edu/robhamm/mcd4/jfp97txt.htm.