Cost-effectiveness of MRI and PET imaging for the evaluation of axillary lymph node metastases in early stage breast cancer.

BACKGROUND: UK guidelines for breast cancer recommend axillary nodal assessment via surgical methods such as sentinel lymph node biopsy (SLNB). However, these procedures are associated with adverse effects such as lymphoedema. Magnetic resonance imaging (MRI) and positron emission tomography (PET) are non-invasive imaging techniques. The aim of this study is to evaluate the cost-effectiveness of MRI and PET compared with SLNB for assessment of axillary lymph node metastases in newly-diagnosed early stage breast cancer patients in the UK.
METHODS: An individual patient discrete-event simulation model was developed in SIMUL8(®) to estimate the lifetime costs and benefits of replacing SLNB with MRI or PET, or adding MRI or PET before SLNB. Effectiveness outcomes were derived from a recent systematic review; patient utilities and resource use data were sourced from the literature.
RESULTS: Based on our analysis the baseline SLNB strategy is dominated by the strategies of replacing SLNB with either MRI or PET. The strategy of replacing SLNB with MRI has the highest total quality-adjusted life years (QALYs) and lowest total costs. However, clinical evidence for MRI is based on a limited number of small studies and replacing SLNB with MRI or PET leads to more false-positive and false-negative cases. The strategy of adding MRI before SLNB is cost-effective, but subject to greater uncertainty.
CONCLUSIONS: Based on this analysis the most cost-effective strategy is to replace SLNB with MRI. However, further large studies using up-to-date techniques are required to obtain more accurate data on the sensitivity and specificity of MRI.