Results of a phase 3 trial support the use of 18F-sodium fluoride (18F-NaF) over 99mTc-methylene diphosphonate (99mTc-MDP) for the detection of bone metastasis.
PET-CT with 18F-NaF proved more accurate than single-photon emission CT (SPECT) with 99mTc-MDP for detecting bone metastasis in patients with high-risk prostate or breast cancer. These results were published in The Lancet Oncology.
The trial (MITNEC-A1; ClinicalTrials.gov Identifier: NCT01930812) included 261 evaluable patients with high-risk prostate cancer (n=204) or breast cancer (n=57) who required bone scintigraphy for the detection of metastasis.
The median age was 68.8 years in the prostate cancer group and 58.5 years in the breast cancer group. All prostate cancer patients and 4% of breast cancer patients were men. A majority in both groups (79% and 81%, respectively) were White.
Prior treatments (in the prostate and breast cancer groups, respectively) included primary surgery (42% and 79%), radiotherapy (26% and 56%), chemotherapy (4% and 65%), androgen deprivation therapy (61% and 0%), and hormone therapy (0% and 54%).
Each patient underwent 18F-NaF PET-CT and 99mTc-MDP SPECT within 14 days of each other. The overall accuracy of the 2 imaging modalities — based on independent reviews from 2 experts for each modality — was compared with histopathologic, clinical, and imaging outcomes observed during a 24-month follow-up (reference standard).
According to the reference standard, 42% of patients had bone metastases. Metastases were more likely in patients with prostate cancer (44%) than in those with breast cancer (33%).
Sensitivity was significantly higher with 18F-NaF PET-CT than with 99mTc-MDP SPECT (78.9% and 63.3%, respectively; P =.0007). The same was true for negative predictive value (85.4% and 76.9%, respectively; P =.0006) and accuracy (84.3% and 77.4%, respectively; P =.016).
However, 18F-NaF PET-CT and 99mTc-MDP SPECT had similar specificity (88.2% and 87.5%, respectively; P =.86) and positive predictive value (82.7% and 78.4%, respectively; P =.038).
There were 65 patients who had metastatic bone lesions on both scans. In this group, the 18F-NaF PET-CT scans detected significantly more lesions than the 99mTc-MDP SPECT scans (P <.0001).
During 18F-NaF PET-CT , patients’ blood pressure and heart rate were observed to decrease between baseline and 60 minutes after 18F-NaF injection, but these changes were not considered clinically relevant. No grade 1 or higher adverse events occurred during 18F-NaF PET-CT.
“Considering all the advantages and the ability to detect bone metastasis with higher sensitivity and accuracy, 18F-NaF has the potential to displace 99mTc-MDP as the bone imaging radiopharmaceutical of choice,” the researchers concluded.
Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Bénard F, Harsini S, Wilson D, et al. Intra-individual comparison of ¹⁸F-sodium fluoride PET–CT and 99mTc bone scintigraphy with SPECT in patients with prostate cancer or breast cancer at high risk for skeletal metastases (MITNEC-A1): A multicentre, phase 3 trial. Lancet Oncol. Published online November 4, 2022. doi:10.1016/S1470-2045(22)00642-8