Abstract
BACKGROUND: Osteosarcoma (OS) is one of the most common primary malignant bone tumors. At present, research on the value of quantitative (99m)Technetium-methylene diphosphonate single photon emission computed tomography/computed tomography ((99m)Tc-MDP SPECT/CT) for predicting neoadjuvant chemotherapy (NACT) efficacy in OS is limited. The purpose of this study was to assess the predictive value of quantitative (99m)Tc-MDP SPECT/CT in predicting NACT efficacy in OS. METHODS: This retrospective study collected (99m)Tc-MDP bone scans and quantitative (99m)Tc-MDP SPECT/CT data of all OS patients from February 2019 to February 2025 at Beijing Jishuitan Hospital, Capital Medical University. The NACT efficacy was assessed based on postoperative pathology. The predictive value of maximum tumor/nontumor radioactive count (T/NTmax), and maximum standardized uptake value (SUVmax) before and after NACT were evaluated. The percentage change of T/NTmax [△T/NT, △T/NT = 100% × (Post-T/NTmax - Pre-T/NTmax)/Pre-T/NTmax] and SUVmax [△SUVmax, ΔSUVmax = 100% × (Post-SUVmax - Pre-SUVmax)/Pre-SUVmax] were also analyzed. RESULTS: A total of 67 patients with OS were enrolled in this retrospective study, including 26 patients with good efficacy and 41 patients with poor efficacy. Post-SUVmax was significantly lower in the good efficacy group than that in the poor efficacy group [19.1 (7.4, 37.3) vs. 34.9 (21.6, 60.8), P=0.006]. The good efficacy group showed significantly greater reductions in ΔT/NTmax [-20.2% (-37.7%, 1.7%) vs. 24.3% (-18.9%, 77.1%), P=0.004] and ΔSUVmax [-32.5% (-60.3%, -13.3%) vs. 21.0% (-11.0%, 48.3%), P<0.001] compared to the poor efficacy group. ΔSUVmax showed a significantly higher area under the curve (AUC) than ΔT/NTmax (0.811 vs. 0.712, P=0.021), indicating higher predictive value. CONCLUSIONS: Quantitative (99m)Tc-MDP SPECT/CT is an efficient technique for predicting NACT efficacy in OS.