Information Technology Reference
In-Depth Information
The case information for the second run that has specific personal information is the
following:
Case 2: we use the following specific information (with personal information):
Suppose that the patient (Michael Dodd) is diagnosed with (HNPCC) colon cancer
stage III.
Michael's father had colon cancer, the time between the diagnosis and the death was 3
years.
Michael's older sister had colon cancer, the time between the diagnosis and the death
was 4 years.
The information stored in the knowledge database is contained in Table 1.
Using the input information in case 2, we are able to get the revised 5-year survival chance.
Figure 8 is the output screen capture for case 2.
Fig. 8. A screen capture of the individualized 5-year survival probability for a person with
colon cancer of stage III
As you can see from the output in Figure 8, the 5-year survival probability is revised down
words. Since in this case, we have more information (patient's father's cancer history;
patient's older sister's cancer history), the evidence based reasoning software takes the new
information into account and produces more accurate output. With regard to the event of 5-
year survival, these evidences reduce the probability. Thus, they are negative evidences
according to our evidence theory. Specifically, the 5-year survival probability is revised from
35-65% down to 15-45%. The following is the rationale and steps to get this new result.
1.
We first calculate the degree of prior probability (in this case, take the data from Table 1
( 65%)) as follows:
degree(prior)
= 10 log
10
(0.65)
= - 1.9
