The 18F-FDG PET/CT response to radiotherapy for patients with spinal metastasis correlated with the clinical outcomes

Abstract

PurposeTo evaluate the potential role of 18F-fluorodeoxyglucose-positron emission tomography/computerized tomography (FDG-PET/CT) for predicting treatment response after radiotherapy (RT) in patients with spinal metastases.Materials and methodsA retrospective analysis was performed of 42 patients with spinal metastases who received RT from January 2010 to December 2014. All patients underwent FDG-PET/CT before and after treatment. Changes in metabolic responses, expressed as the maximum, mean, peak standardized uptake values (SUVmax, SUVmean, SUVpeak), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were analyzed to determine their association with clinical outcomes.ResultsThe median age at the time of spinal metastasis diagnosis was 58 years. Median progression-free survival (PFS) and overall survival after RT were 15 months and 22.4 months, respectively. RT produced a significant decrease in SUVmean (2.27 to 1.41), SUVmax (6.87 to 2.99), SUVpeak (5.75 to 2.33) and TLG (52.84 to 24.17) when compared with the baseline values (p<0.001). The mean pain score decreased from 3.86 before RT to 0.79 after RT (p<0.001). There were significant linear relationships between maximum SUV and pain scores at baseline (r = 0.321, p = 0.038) and after treatment (r = 0.369, p = 0.016) as well as TLG at baseline (r = 0.428, p = 0.005) and after treatment (r = 0.403, p = 0.009). Local progression after treatment was identified in 12 patients (28.6%). Univariate analyses showed that >70% reduction in maximum SUV after treatment was independently associated with good PFS (p = 0.036).ConclusionsRT is an effective treatment for patients with spinal metastases, and there were significant changes in PET parameters compared with baseline. The metabolic response measured by SUV and TLG changes in FDG-PET/CT correlated with the clinical outcomes, especially with shorter PFS in patients who had higher residual maximum SUV after treatment.

Radiomic signature of 18F fluorodeoxyglucose PET/CT for prediction of gastric cancer survival and chemotherapeutic benefits

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“…Youland et al 64 retrospectively evaluated pre‐ and post‐treatment PET‐CT scans in patients with metastatic melanoma treated with SBRT and found that the incidence of flare effect could be significantly reduced when the first scan is performed >2.3 months after SBRT. Using PERCIST criteria, Choi et al evaluated whether changes in PET parameters after treatment with RT for spinal metastases can predict clinical outcomes 65 . They reported that metabolic response to RT, as measured by a change in SUV between baseline and post‐treatment, was predictive of progression‐free survival (PFS) and that a higher residual SUV post‐treatment was associated with a relative resistance to pain relief.…”