Incidence of bone metastases in patients with organ-specific cancers: A nationwide population-based cohort study.

ABSTRACT

BACKGROUND: Bones are the third most common site of metastasis, although bone metastasis (BM) incidence varies widely. This study investigated the incidence of BM in the most common cancers in Taiwan to present the recent treatment landscape in patients with organ-specific cancers. METHODS: Data from the National Health Insurance Research Database of Taiwan were used to identify adult patients diagnosed with organ-specific cancers between January 1, 2000 and December 31, 2015. Kaplan-Meier analysis was used to quantify cumulative BM incidence at follow-up. BM incidences associated with different cancers were calculated comprehensively and stratified by sex, age group and follow-up periods, and age- and sex-adjusted hazard ratios (HRs) of BM were calculated using multivariate Cox regression analysis. RESULTS: Among 938 776 participants (mean follow-up, 9.2 years), liver (19.6%), colorectal (17.1%) and lung (15.1%) cancers were most commonly associated with BM. The mean interval between a primary cancer diagnosis and BM was 2 years. BM incidence varied widely among cancers; lung cancer (3213 per 105 person-years) was associated with the highest BM risk, followed by oesophageal, prostate and breast cancer. HRs of BM were significantly higher for lung cancer (HR = 8.1) than for other cancers. CONCLUSION: The estimated BM incidence provided insight into oncological clinical practice trends in the Asia-Pacific region. BM incidence may vary among populations. Understanding the principles of clinical evaluation in patients with cancer of unknown primary origin can facilitate appropriate treatment recommendations.