Intraindividual Comparison of F-18–NaF PET-CT vs Tc-99m–MDP SPECT in Detecting Bone Metastasis in High-Risk Prostate and Breast Cancers

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In a Canadian phase III trial (MITNEC-A1) reported in The Lancet Oncology, Bénard et al found that fluorine-18–sodium fluoride (F-18–NaF) positron-emission tomography-computed tomography (PET-CT) was more accurate in detecting skeletal metastases vs technetium-99m–methylene diphosphonate (Tc-99m–MDP) single-photon emission CT (SPECT) in intraindividual comparisons in patients with high-risk prostate or breast cancers.

Study Details

In the multicenter trial, 261 patients (204 with prostate cancer and 57 with breast cancer) with high risk/clinical suspicion for bone metastasis but no previously documented bone involvement, enrolled between July 2014 and March 2017, underwent both Tc-99m–MDP SPECT and F-18–NaF PET-CT scans within 14 days. Reviewers interpreted findings of each modality without knowledge of other imaging findings. A combination of histopathologic, clinical, and imaging follow-up for up to 24 months was used as the reference standard to assess imaging results.

Key Findings

Median follow-up was 735 days (interquartile range = 727­–750 days). According to reference methods, 109 (42%) of the 261 patients had bone metastases.

F-18–NaF PET-CT was more accurate than Tc-99m–MDP SPECT in detecting metastatic lesions identified by reference methods: 84.3% (95% confidence interval [CI] = 79.9%–88.7%) vs 77.4% (95% CI = 72.3%–82.5%), with a difference of 6.9% (95% CI = 1.3%–12.5%, P = .016).

Sensitivity was 78.9% vs 63.3% (P = .0007); specificity was 88.2% vs 87.5% (P = .86); positive predictive value was 82.7% vs 78.4% (P = .38); and negative predictive value was 85.4% vs 76.9% (P = .0006).

No adverse events were reported.

The investigators concluded, “[F-18]-NaF has the potential to displace [Tc-99m]-MDP as the bone imaging radiopharmaceutical of choice in patients with high-risk prostate or breast cancer.”

François Bénard, MD, of BC Cancer Research Institute, Vancouver, is the corresponding author for The Lancet Oncology article.  

Disclosure: The study was funded by the Canadian Institutes of Health Research. For full disclosures of the study authors, visit

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