Monitoring the Therapy of Osteosarcoma Metastases with SPECT/CT

Abstract

A 43-year-old man presented with a history of osteogenic sarcoma of lower third of the right femur bone. In dynamic monitoring (2011–2018) in the Nuclear Medicine Department of N.N. Blokhin National Medical Research Centre of oncology, Moscow, Russia a total of 48 radionuclide diagnostic studies were performed: 24 bone scans, 19 SPECT/CT (areas of interest) and 5 dynamic scintigraphies. The results of radionuclide diagnostics allowed to identify 6 episodes of progression of the underlying condition earlier than X-ray methods of imaging in the form of appearance of new metastases in bones, right lung and continued growth of some previously identified metastases in different periods of observation. Time between relapse detection and treatment ranged from 1 to 12 months. First of all it was because of the clinicians distrust to the results of radionuclide studies that were not confirmed by X-Ray at early stages. During the relapse treatment process patient received standard and innovative therapies: 10 courses of polychemotherapy, two surgeries for endoprosthesis replacement of the right knee and femur, upper lobectomy of the right lung, radiation therapy for metastasis in the left iliac bone (total boost dose – 52 Gy), radiation therapy on the CyberKnife device on metastases in the head of the 7th right rib and metastasis in the right lung, 2 sessions of ultrasonic thermal ablation on the HIFU in the area of metastases in the neck of the right femur,5 courses of bisphosphonates. The method of hybrid imaging of SPECT/CT allowed us to reliably monitor the effectiveness of the therapy. Postradiation changes in osteosarcoma metastases consisted in a decrease bone (pathological) metabolism, while radio-intensity indices did not change. For the first time we observed the effect of ultrasonic thermal ablation in the treatment of bone metastases. The effect of the treatment manifested very quickly and we visualized it as a defect of accumulation of radiopharmaceutical, which is a consequence of damage to the tumor vessels and tissue necrosis. In the observation of osteosarcoma recurrence SPECT with osteotropic radiopharmaceuticals demonstrates advantages over PET with 18F-FDG. Bone scan and SPECT/CT have proven to be reliable methods of dynamic control of a patient with osteosarcoma.