The MULTI-MIBI Study, recently published in the European Journal of Nuclear Medicine and Molecular Imaging, represents a significant step forward in the effort to build a more intelligent and proportionate diagnostic pathway. The study tested the feasibility of using [99mTc]Tc-sestamibi (MIBI) SPECT/CT across multiple UK centres to differentiate benign from malignant renal tumours at the time of diagnosis, with encouraging results.
This pragmatic, multi-centre feasibility study recruited 50 patients with newly diagnosed cT1 renal masses across six NHS sites. The scan was well tolerated, logistically achievable, and produced images of diagnostic quality in every case. Importantly, qualitative scan interpretation showed very high inter-reader agreement (Gwet’s coefficient ~0.94), providing reassurance that this imaging modality can be reproducible in real-world practice without the need for significant additional training for scan acquisition or interpretation.
While this feasibility study was underpowered to report accurate measures of diagnostic accuracy, initial results were encouraging. Sensitivity for malignancy was 97%, with a negative predictive value of 87.5%, meaning MIBI SPECT/CT was a reliable tool for ruling out malignant disease — a critical requirement for any de-escalation tool. Specificity was more modest (53.8%), but would in practice mean that the number of patients undergoing surgery for benign disease could be halved with the introduction of this imaging technique. There was one notable false negative – a low-grade eosinophilic papillary RCC. A larger trial is planned to report real-world measures of diagnostic accuracy and implications for clinical practice.
The MULTI-MIBI study represents an important pivot toward a more tailored approach to managing small renal masses. It demonstrates that a large-scale trial of MIBI SPECT/CT for small renal tumours is feasible, and affirms its potential role as a non-invasive, safe, and widely accessible imaging test.
Future work will help determine whether this imaging approach can reduce unnecessary surgeries, improve patient outcomes, and offer a cost-effective alternative to current standard pathways.
More broadly, this work contributes to a growing effort to refine how we assess and manage incidentally detected renal tumours. It supports a more proportionate, evidence-based approach — one that accounts for tumour biology and individual patient risk, and avoids overtreatment where possible.
Written by: Hannah Warren,1,2 and Maxine Tran, MBBS, PhD, FRCS (Urol),1,2 on behalf of the MULTI-MIBI Investigators
- Division of Surgery and Interventional Science, University College London, London, UK.
- Specialist Centre for Kidney Cancer, Urology Department, Royal Free Hospital, London, UK.