To investigate the predictive value of [18F]-fluoromethylcholine positron emission tomography/computed tomography (PET/CT)-derived parameters on progression-free survival (PFS) in oligometastatic prostate cancer patients treated with stereotactic body radiation therapy (SBRT).
In [18F]-fluoromethylcholine PET/CT scans of 40 consecutive patients with ≤4 metachronous metastases treated with SBRT we retrospectively measured the number of metastases, standardized uptake values (SUVmean, SUVmax, SUVpeak), metabolically active tumor volume (MATV), and total lesion choline uptake. Partial-volume correction was applied using the iterative deconvolution Lucy-Richardson algorithm.
Thirty-seven lymph node and 13 bone metastases were treated with SBRT. Thirty-three patients (82.5%) had 1 lesion, 4 (10%) had 2 lesions, and 3 (7.5%) had 3 lesions. After a median follow-up of 32.6 months (interquartile range, 35.5 months), the median PFS was 11.5 months (95% confidence interval 8.4-14.6 months). Having more than a single metastasis was a significant prognostic factor (hazard ratio 2.74; P = .03), and there was a trend in risk of progression for large MATV (hazard ratio 1.86; P = .10). No SUV or total lesion choline uptake was significantly predictive for PFS, regardless of partial-volume correction. All PET semiquantitative parameters were significantly correlated with each other (P ≤ .013).
The number of choline-avid metastases was a significant prognostic factor for progression after [18F]-fluormethylcholine PET/CT-guided SBRT for recurrent oligometastatic prostate cancer, and there seemed to be a trend in risk of progression for patients with large MATVs. The lesional level of [18F]-fluoromethylcholine uptake was not prognostic for progression.
International journal of radiation oncology, biology, physics. 2018 Feb 13 [Epub ahead of print]
Matthijs Cysouw, Esther Bouman-Wammes, Otto Hoekstra, Alfons van den Eertwegh, Maartje Piet, Jeroen van Moorselaar, Ronald Boellaard, Max Dahele, Daniela Oprea-Lager
Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands. Electronic address: ., Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands., Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands., Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands., Department of Urology, VU University Medical Center, Amsterdam, The Netherlands., Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands; Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, Groningen, The Netherlands.