Table 14: Two way sensitivity analysis of chemotherapy and radiotherapy in CT positive
patients
Chemotherapy Costs | ||||||||
Radiotherapy costs |
4000 |
6000 |
8000 |
9784 |
10000 |
12000 |
14000 | |
6000 |
79436.1 |
87582.1 |
95728.1 |
102994.3 |
103874.0 |
112020.0 |
120166.0 | |
8000 |
66571.8 |
74717.7 |
82863.7 |
90129.9 |
91009.7 |
99155.6 |
107301.6 | |
10000 |
53707.4 |
61853.3 |
69999.3 |
77265.5 |
78145.3 |
86291.3 |
94437.2 | |
12000 |
40843.0 |
48989.0 |
57134.9 |
64401.1 |
65280.9 |
73426.9 |
81572.8 | |
13922 |
28480.3 |
36626.3 |
44772.3 |
52038.5 |
52918.2 |
61064.2 |
69210.2 | |
14000 |
27978.6 |
36124.6 |
44270.6 |
51536.8 |
52416.5 |
60562.5 |
68708.5 | |
16000 |
15114.2 |
23260.2 |
31406.2 |
38672.4 |
39552.1 |
47698.1 |
55844.1 | |
18000 |
2249.90 |
10395.8 |
18541.8 |
25808.0 |
26687.8 |
34833.7 |
42979.7 | |
20000 |
-10614.4 |
-2468.5 |
5677.4 |
12943.6 |
13823.4 |
21969.4 |
30115.3 |
In the CT positive results we see that as the chemotherapy cost increase the ICER starts
to increase, however when the radiotherapy cost increase the ICER start to fall and eventually
PET comes to dominates the CWU strategy. A possible explanation of the difference between
the results of the CT positive and CT negative patients is the different distribution of the
underlying disease. The chemotherapy costs raise in both N2/3 and M1 and so the ICER
increases as chemotherapy costs increase. But, because there are nearly 1.3 more futile
radiotherapies in the CWU strategy compared to only 0.075 in the PET strategy; we see that at
low prices for radiotherapy this means that PET is the far more expensive strategy, but as
radiotherapy costs start to increase then so do the total costs for the CWU strategy reducing the
difference in costs between the two strategies making PET strategy more cost effective.
Testing the NICE distribution
The NICE paper used a different underlying distribution of lung cancer and, although,
their distribution improved on some of the assumptions made in previous model it was felt that
it may have had a rate of metastasis that was too high for N0/1 patients and that overall the
number of N2/3 patients was too low. Therefore, their distribution was not used as the base
case. Although it did have the added benefit in suggesting that the rate of metastasis would not
be the same for both N0/1 and N2/3 patients so it was decided to test the distribution.
Table 15: The NICE distribution
Cost $A |
Incremental |
QALYS |
Incremental |
ICER | |
NICE distribution of lung cancer patients___________________________________________________ | |||||
CT negative PET CT negative CWU |
1361521.06 1391567.23 |
30,046 |
215.64808 215.42801 -0.22 DOMINATED |
NICE distribution of lung cancer patients______________________________________________ | |||||
CT positive PET |
598912.2 |
_______________70.25457_____________ | |||
CT positive CWU |
671965.1 |
73053 |
73.24 |
________2.98 |
24484.222 |
It was found that for CT negative patients the PET strategy dominated the CWU
strategy this was also what was found in the NICE model with sending all patients to
24