patients. Therefore despite the favourable overall ICER of $A 20,291 between the CWU and
PET strategy this hides large potential differences between the CT negative and CT positive
patients.
Testing the Viney et al RCT Trial
The accuracy of the model was tested by comparing it to the Viney et al randomised
control trial with the control group (no PET scan) containing 92 patients and a PET group of 91
patients. In the control arm, 90 of the patients underwent surgery compared with 87 in the PET
arm. The two arms closely resembled the two strategies that are presented here, although some
patients did undergo further tests. There were 7 patients who had mediastinoscopy in the PET
arm and 4 patients that had mediastinoscopy in the control arm. The trial consisted of mainly
stage I patients who therefore had limited mediastinal lymph node involvement and low rate of
distant metastasis, thus the majority of the patients in both arms proceeded straight to
thoractomy explaining the low number of mediastinoscopies carried out in the trial.41
The distribution of N0/1 and N2/3 candidates in the trial was inputted into the model
and the percentage of patients going to mediastinoscopy was changed to represent the
movements of the actual population in the trial. The model predicted that for the no PET arm
there would be 82.77 patients having surgery compared to the trial where 90 patients
underwent a thoractomy. The main reason for the difference was because the rate of metastasis
in model presented here seems to be too high or at least for those patients with stage I disease.
The rate of metastasis was then changed to 5% in the model the rate used in other economic
models such as Dietlein and this gave a result of 87.35 patients proceeding to thoractomy.42
The model predicted for the PET arm that there would be 81.86 patients that would receive
surgery again an underestimation of the 87 patients that did receive surgery in the trial. Once
again changing the rate of metastasis to 5% provided a result closer to the trial result with 87.1
patients receiving a surgery. Therefore, it would seem, at least, for stage I NSCLC patients the
rate of metastasis is too high in the model presented here.
The HTBS study with its similar model to the one presented here assessed the Van
Tintertern et al trial, which differed from the Viney trial in that any patients with NSCLC were
recruited into the model instead of just stage I and II patients. It was found that the HTBS
model predicted the trial well with their model predicting the difference in futile operations
between the CWU and PET arms being that PET saved 17 operations per 100 in the model;
whereas the Dutch trial showed there were actually 16 operations per 100 saved.4344
The results of testing the models against the random clinical trails suggest that the
overall level of metastasis for all patients with NSCLC maybe correct. However, as the NICE
study suggests, the rate of metastasis may change depending on which stage of NSCLC the
patients have and with the results here actually suggesting that for stage I candidates the rate of
distant metastasis maybe too high.45
41 Viney, R. C., M. J. Boyer, et al. (2004). "Randomized controlled trial of the role of positron emission
tomography in the management of stage I and II non-small-cell lung cancer.[see comment]." Journal of Clinical
Oncology 22(12).
42 Dietlein, M., K. Weber, et al. (2000). "Cost-effectiveness of FDG-PET for the management of potentially
operable non-small cell lung cancer: priority for a PET-based strategy after nodal-negative CT results." Eur J Nucl
Med 27(11): 1598-609.
43 Bradbury et al. Health Technology Board Scotland, “Positron emission tomography (PET) imaging in cancer
management” October 2002. “Economic Evaluation”, pp.23-24.
44 van Tinteren, H., O. S. Hoekstra, et al. (2002). "Effectiveness of positron emission tomography in the
preoperative assessment of patients with suspected non-small-cell lung cancer: the PLUS multicentre randomised
trial." Lancet 359(9315).
45 National Institute of Health and Clinical Effectiveness, “The Diagnosis and treatment of Lung Cancer; Methods,
Evidence and Guidance. National Collaboration Centre of Acute Care. 2005. Appendices p.271.
19
More intriguing information
1. CONSUMER ACCEPTANCE OF GENETICALLY MODIFIED FOODS2. The name is absent
3. The name is absent
4. The name is absent
5. THE WELFARE EFFECTS OF CONSUMING A CANCER PREVENTION DIET
6. The Global Dimension to Fiscal Sustainability
7. How we might be able to understand the brain
8. Whatever happened to competition in space agency procurement? The case of NASA
9. If our brains were simple, we would be too simple to understand them.
10. The name is absent