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

the CWU patients, therefore there are more patients that benefit from a reduction in surgical
morbidity than in the PET strategy. Therefore, the ICER of PET over the CWU for CT
negative patients actually becomes less cost effective with it rising to $A19,268 per QALY.

This is also the case for the CT positive patients with the number of QALYs increasing
in both CWU and PET with more surgeries taking place in the CWU patients again and so the
ICER becomes less cost effective rising to 59,630 per QALY. While the opposite is true when
the rate of surgical morbidity increases with the ICERs improving to $A11,728 and $A 46,161
per QALY in both the CT positive and CT negative patients. The sizes of effects are relatively
tight around the baseline results showing that this is a relatively robust result.

Rate of upstaging during Surgery

The rate of upstaging to radical radiotherapy and chemotherapy in N2/3 M0 patients
undergoing thoractomy was 10%. This was increased and decreased by 50% to take into the
consideration the uncertainty of this parameter.

Table 12: Rate of upstaging during surgery for CT negative and CT positive patients

The QALYS were not affected by this change because it is assumed there is no
difference in terms of quality of life or life expectancy for N2/3 M0 patients undergoing
chemotherapy or a combination of chemotherapy and radiotherapy in an attempt to downstage
the cancer. This maybe an incorrect assumption, but there is no evidence to suggest that there
is indeed a difference and so it was felt rather than add in a further baseless assumption to the
model the quality of life and life expectancy would be left unchanged.

However, the costs do increase for both CT negative and CT positive patients as the
rate of upstaging increase with more N2/3 M0 patients being correctly moved to more
expensive chemotherapy and radiotherapy. The ICER in CT negative patients becomes more
cost effective decreasing to $11,205 per QALY and as the rate of upstaging increases due to
more CWU patients undergo surgery, whether this is correct or futile, relative to the PET
patients and this incurs greater cost but without any improvement in benefits. When the rate of
upstaging is decreased this has the opposite effect as fewer patients in the CWU arm undergo
expensive radiotherapy and chemotherapy with no change to the benefits and so the ICER
increase to $A 16,269 per QALY.

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