Prevalence of bone pain decreases as lymph node stage increases in nonsmall cell lung cancer patients

According to lung cancer guidelines, positron emission tomography scan is recommended for initial evaluation of bone metastasis. However, guidelines differ in their recommendations for when it should be used. We investigated the appropriate use of bone imaging in nonsmall cell lung cancer (NSCLC) patients. One hundred seventy-seven consecutive NSCLC patients who had distant metastases at presentation and were admitted between January 2012 and April 2016 were retrospectively reviewed. Among patients with bone metastases, we explored bone pain, number of bone metastases, location of bone metastases, and clinical tumor (T) and lymph node (N) classification. Sixty-three patients had bone metastases. There was a trend toward an increase in prevalence of bone metastases as lymph node stage increased. The prevalence of bone pain significantly decreased as N stage increased (p = 0.017). N0 and N2-3 patients were more likely to have multiple bone metastases (p = 0.038). Compared with patients who had a single bone metastasis, patients with multiple metastases had a significantly higher probability of having at least 1 bone metastasis located in the thorax or upper abdomen. All N0 patients have at least 1 bone metastasis in the thorax or upper abdomen. Clinical N0 NSCLC patients with bone metastasis are likely to have bone pain and have multiple bone metastases. N2-3 patients are more likely to have bone metastases but less likely to have bone pain. If NSCLC patients do not have bone pain, and CT of the chest and upper abdomen does not reveal any lymph node or bone metastasis, further survey for bone metastases may be omitted; bone imaging should be performed in N2 and N3 patients regardless of symptoms.