Fluorine‐18‐fluorodeoxyglucose‐positron emission tomography evaluation in metastatic bone lesions in lung cancer: Possible prediction of pain and skeletal‐related events

Background Fluorine‐18‐fluorodeoxyglucose‐positron emission tomography (FDG‐PET) uptake in primary lesions has been well studied, but little information is available about metastatic bone lesions in patients with lung cancer. The present study was performed to evaluate the relationships between metastatic bone FDG uptake and clinical parameters in patients with lung cancer. Methods FDG uptake was evaluated as the maximum standardized uptake (SUVmax) value of each targeted bone lesion, and the bone to primary lesion ratio of SUVmax (B/P ratio) was calculated. Forty‐nine patients (27 men and 22 women) with a diagnosis of lung cancer (small cell lung cancer [SCLC], n = 7; non‐small cell lung cancer [NSCLC], n = 42) with bone metastasis, and a total of 185 bone metastatic lesions were evaluated. Results The SUVmax in bone and the B/P ratio were significantly higher in patients with pain and subsequent development of skeletal‐related events than in those without pain or skeletal‐related events, respectively. In addition, the SUVmax in metastatic bone lesions and the B/P ratio in SCLC were significantly lower than those in NSCLC, despite similar FDG uptake in the primary tumor. Conclusion Our findings suggest that FDG‐PET evaluation in metastatic bone lesions could be useful to predict initial pain and subsequent clinical outcomes of local bone status in initially diagnosed lung cancer patients with bone metastasis. In addition, our results suggest that there could be histological differences in the biological activity of bone metastatic lesions in lung cancer, especially between SCLC and NSCLC.