Maira Zia*, Elin Lundström, Johanna Mårtensson, Mark Lubberink, Aglaia Schiza and Anders Sundin
RECIST 1.1 tumour size measurements on CT/MRI are the mainstay of cancer therapy monitoring. However, bone metastases are consistently difficult to evaluate for hormonal therapy response often escaping CT detection. This study aimed to assess dynamic and static [18F]sodium fluoride-([18F]NaF)-PET/MRI by combining standardized uptake value (SUV) and net influx rate (Ki) from PET with the apparent diffusion coefficient (ADC), proton density fat fraction (PDFF) and effective transverse relaxation rate (R2*) from MRI for monitoring hormonal therapy effect on bone metastases. In this prospective study, three breast cancer patients underwent a 60-minute dynamic whole-body [18F]NaF-PET/MRI before and after hormonal therapy. In PET images, pelvic and spine metastases (approx. n=10/patient) with high/intermediate uptake were delineated by applying an adaptive threshold algorithm to provide SUVmean and SUVmax. Pharmacokinetic modeling was performed and Ki was calculated using a two-tissue reversible model. VOI measurements of ADC, PDFF and R2* utilized the OLEA medical software. The changes between baseline and follow-up data were calculated, statistically analysed and utilized linear regression. [18F]NaF-PET/MRI provided a powerful method for monitoring hormonal therapy response in breast cancer bone metastases as reflected by decreases in SUV and Ki. MRI parameters showed changes consistent with therapy response, although only R2* reached statistical significance.
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Journal of Cancer Clinical Trials received 95 citations as per Google Scholar report
