Molecular Imaging in the selection and evaluation of response in patients treated with Radium-223 in six different solid tumors: A single center experience
Abstract Objective: Evaluate impact after 223 Ra therapy and 18 F-NaF (sodium fluoride) PET/CT in the selection and evaluation of response in patients treated with 223 Ra in six different solid tumors. Material and Methods: Twenty patients with metastatic castration-resistant prostate cancer (mCRPC), seven metastatic castration-sensitive prostate cancer (mCSPC), three osteosarcoma, two breast cancer, two non-small cell lung cancer (NSCLC), one chondrosarcoma, one chordoma and one patient lung neuroendocrine carcinoma. Three groups of study were defined according total skeletal tumor-burden obtained by 18 F-NaF PET/CT, group 1 <1000cm 3 , group 2 1001–2999cm 3 and group 3 >3000cm 3 VOI´s. A semi-quantitative comparison was performed measuring the SUVmax values of VOIs values in all bone metastases in each patient previous to receive the first cycle of 223 Ra, after 3 and 6 cycles. Results: 30 patients non-progress disease was documented after 24±4 weeks. 8 patients progress disease was presented after three cycles of 223 Ra, two patients with osteosarcoma, four patients with mCRPC, one patient with chondrosarcoma and one patient with NSCLC. Group 1 patients showed better response rates compared to group 3 (p<0.05). Group 2 patients who showed improvement clinical and radiological, had prostate malignancies compared to those in the same group, but non-prostatic malignancies (p<0.05). No significant difference in group 2 patients compared to group 3 (p<0.67). Symptomatic skeletal-related event was observed in 7 patients. Conclusion: 18 F-NaF PET/CT allows to identify patients who show osteoblastic bone activity and discard or confirm progression in the interval PET/CT image, allowing change of treatment, reducing costs. High tumor-burden strongly suggests a poor response to treatment