FDG-PET Predicts Pain Response and Local Control in Palliative Radiotherapy With or Without Systemic Treatment in Patients With Bone Metastasis From Non–small-cell Lung Cancer

Abstract

IntroductionWe sought to evaluate the value of fluorine-18 fluorodeoxyglucose positron emission tomography (PET) in predicting the pain severity, pain response, and in-field tumor control after palliative radiotherapy (RT) in patients with non–small-cell lung cancer (NSCLC) bone metastases. Materials and MethodsThe present retrospective, institutional review board–approved study involved 74 patients with NSCLC and 185 bone metastatic lesions. All patients had undergone PET-computed tomography (CT) scans before and after RT. The pain scores were determined using a numerical rating scale, and the maximal standardized uptake value (SUVmax) at each location was recorded. The pain scores and responses to RT were compared using the pre-RT SUVmax and SUVmax changes after RT. Cox regression analyses were performed to identify the prognostic factors for in-field progression-free survival (PFS) and in-field event-free survival (EFS). ResultsThe pre-RT SUVmax correlated with the initial pain scores (r = 0.885, P < .001), and the decrease in the SUVmax after RT was associated with the pain response to RT (P = .001). During the follow-up period, 47.03% and 38.92% of the lesions showed in-field tumor radiographic progression and in-field events, respectively. The Cox regression analyses showed that a higher pre-RT SUVmax (≥ 8.2) was an independent prognostic factor of worse in-field PFS and worse in-field EFS (hazard ratio [HR] 1.42 and 1.46; P = .044 and P = .005, respectively) and that a greater SUVmax decrease (≥ 28.3%) after RT was an independent prognostic factor of better in-field PFS and better in-field EFS (HR 0.59 and 0.60, respectively; P < .001 for both). ConclusionIn patients with NSCLC osseous metastasis treated with palliative RT, the pre-RT SUVmax predicted the initial pain severity and local control. Moreover, the change in the SUVmax after RT predicted the pain response and local control.