Bone Metastases in Newly Diagnosed Colorectal Cancer by Tumor Location: a Population-based Study

Purpose Bone metastasis (BM) in colorectal cancer (CRC) is rare and data on population-based incidence is lacking. We aimed to evaluate the incidence of BM and the risk factors for BM in CRC. Methods The Surveillance, Epidemiology, and End Results (SEER) database was interrogated as part of the analysis. We used multivariable logistic and Cox regression analyses to determine predictors for the presence of BM at diagnosis, and the elements associated with poor survival. Kaplan–Meier analysis was used to estimate the survival difference among subgroups. Results A total of 166,388 adult patients were identified between 2010 and 2013 as being diagnosed with CRC. Of these, 1,659 patients developed BM representing 1% of the entire CRC cohort and 5.5% of patients had metastatic disease. The median survival period of patients with BM was merely 11.3 months. We found that extracranial metastases number and tumor site were associated with BM at CRC diagnosis and these parameters were also associated with poorer survival in the BM cohort. Unlike other solid tumors, patients with bone metastasis had poorer survival and the median survival time (MST) was significantly shortened for single metastasis disease or when lung and liver metastasis were present.Conclusions The findings of this study clearly reveal the incidence and prognosis for patients with BM at time of CRC diagnosis. Our findings lend support for positive treatment of BM without other organ metastasis.