Incidence of Patients with Bone Metastases at Diagnosis of Solid Tumors in Adults: A Large Population-Based Study

Background: Bone is one of the most common metastatic sites of solid malignancies. Bone metastases can significantly increase mortality and decrease the quality of life of cancer patients. In the United States, around 350,000 people die each year with bone metastasis. The aim of this study was to analyze and update the incidence and prognosis of bone metastases among solid tumors at the time of cancer diagnosis and its incidence in each solid cancer.Methods: We used the Surveillance, Epidemiology, and End Results (SEER) database to identify patients diagnosed with solid cancers originating outside of bone and joints cancer between 2010-2016. Data were stratified by age, sex, and race. Patients with tumor in suit or with an unknown bone metastases stage were excluded. Then we selected most of sites where cancer often occurred, leaving 2,207,796 patients for the final incidence analysis. For the survival analysis, patients were excluded if they were diagnosed at autopsy or death certificate, as well as patients with unknown follow-up. Incidence of bone metastases and overall survival was compared between patients with different primary tumor sites.Results: We identified 2,470,634 patients, included 426,594 patients with metastatic disease and 113,317 patients with bone metastases, for incidence analysis. The incidence of bone metastases among the metastatic subset is 88.74% in prostate cancer, 53.71% in breast cancer and 38.65% in renal cancer. In descending order, patients with other cancers of the genitourinary system (except renal, bladder, prostate, testicular) (37.91%), adenocarcinoma of the lung (ADC) (36.86%), other Gynecologic (36.02%), small-cell lung cancer (SCLC) (34.56%), non-small cell lung cancer not otherwise specified and others (NSCLC(NOS/Others)) (33.55%) and Bladder (31.08%) cancers. The rate of bone metastases is 23.19% in SCLC, 22.50% in NSCLC(NOS/Others), 20.28% in ADC, 8.44% in squamous cell carcinoma of the lung (SCC) and 4.11% in bronchioloalveolar carcinoma (NSCLC(BAC)). As far as the digestive system is considered, the overall bone metastases rate is 7.99% in esophagus, 4.47% in gastric, 4.42% in hepatobiliary, 3.80% in pancreas, 3.26% in other digestive organs, 1.24% in colorectal 1.00% in anal. Besides, incidence of bone metastases among entire cohort in breast and prostate cancer is 3.73% and 5.69%.Conclusions: The results of this study provide population-based estimates of the incidence for patients with bone metastases at initial diagnosis of their solid tumor. The findings can help clinicians to early detect bone metastases by bone screening in order to anticipate the occurrence of symptoms and favorably improve the prognosis.Funding: This work was funded by the National Natural Science Foundation of China (81501933, 81572214), Zhejiang Provincial Natural Science Foundation of China (LY14H060008), Zhejiang Provincial Medical and Health Technology Foundation of China (2018KY129), Wenzhou leading talent innovative project (RX2016004) and Wenzhou Municipal Science and Technology Bureau (Y20170389).Declaration of Interest: All authors report there are no conflicts of interest related to the present article.