Bone metastases among newly diagnosed cancer patients: a population-based study

(i) To analyze age-adjusted incidence rates of synchronous bone metastases diagnosed alongside primary malignancy from 2010 to 2018 in the US population, (ii) determine the incidence proportions (IPs) and characteristics of synchronous bone metastases among newly diagnosed cancer patients in the USA especially pediatric cases, and (iii) assess the implications of synchronous bone metastases on cancer patient's survival, and identify the survival risk factors for these cancer patients.

Utilizing data from the Surveillance, Epidemiology, and End Results (SEER) program (2010-2018), we calculated age-adjusted IPs and annual percentage change (APC), and employed logistic regression and Cox regression models for our analysis.

3 300 736 cancer patients were identified. The age-adjusted incidence rates of synchronous bone metastases increased from 2010 (18.04/100 000) to 2018 (20.89/100 000; APC: 2.3, 95% confidence interval [CI], 1.4-3.1), but decreased in lung cancer (average APC: -1.0, 95% CI, -1.8 to -0.3). The highest IPs were observed in pediatric neuroblastoma (43.2%; 95% CI, 39.8%-46.7%) and adult small cell carcinoma (23.1%; 95% CI, 22.7%-23.4%). Multivariate logistic analyses revealed that primary tumor characteristics were correlated with higher bone metastases risk. Survival analyses also showed varied prognostic outcomes based on metastasis sites and demographics among cancer patients. Landmark analyses further indicated among long-term cancer survivors (≥3 and ≥5 years), patients with de novo bone metastases had the poorest survival rates compared with those with other synchronous metastases (P < 0.001).

This study provides a population-based estimation of the incidence and prognosis for synchronous bone metastases. Our findings highlight the need for early identification of high-risk groups and multidisciplinary approaches to improve prognosis of cancer patients with de novo bone metastases.