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

The purpose of the present study was to evaluate the prognostic value of the maximal standardized uptake value (SUVmax) from serial positron emission tomography scans in patients with bone metastases from non-small-cell lung cancer. The results showed that the pre-RT SUVmax predicted the initial pain severity and local control. Moreover, the change in the SUVmax after palliative radiotherapy predicted the pain response and local control rate. Introduction: We 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 Methods: The 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). Results: The 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). Conclusion: In 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.