Economic Evaluation of Positron Emission Tomography (PET) in Non Small Cell Lung Cancer (NSCLC), CHERE Working Paper 2007/6

Results

Baseline

The model was built and run in an EXCEL spreadsheet with 100 patients progressing
through the model. In the base case result there were 34.3% of patients who were CT positive
and 65.6% patients who were CT negative. The CT negatives patients comprised of around 48
patients who were potentially surgically operative and close to 17 who were eligible for non
surgical treatment. The results of the CT negative patients are given in table 6.

Table 6: CT negative patients

There is a minute difference between the PET and CWU strategies in the number of
patients that undergo correct operations this includes patients who were correctly staged but
died as a result of surgery. The small difference is accounted for by the CWU patients having
to undergo 82% more mediastinoscopies than the PET arm and therefore having a higher risk
of dying before having a correct operation. This also accounts for the negligible increase in
number of missed operations with more patients dying in mediastinoscopy in the CWU
strategy.

However, the main difference between the two strategies occurs with there being
around a total of 13.44 more futile surgical operations in the CWU strategy compared to only
0.24 in the PET strategy. This result can be mostly explained by 58% of the CWU patients
progressing straight to surgery without undergoing a mediastinoscopy thus accounting for
around 9.7 of the futile operations. The other futile thoractomies can be explained by a more
accurate staging by PET with its high sensitivity and specificity of 0.86 and 0.9 and then
following positive patients up with a mediastinoscopy this allows better results than just
conducting a pure mediastinoscopy due to its low sensitivity of 0.72. Despite the futile
operations the CWU is still on average cheaper than the PET strategy by around $A400 due to
the extra cost of PET scanning. The average QALYs between the two strategies are quite close
with a difference of only 0.026 per patient. The relatively small difference in QALYs and costs
suggests that the two strategies will be very sensitive to changes in model inputs.

There were 34.3% of patients who were CT positive with around 14.6 patients who
were suitable for surgery and 21.6 suitable for non surgical treatment. The baseline results of
the CT positive patients can be seen in table 7.

Table 7: CT positive patients

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