Retrospective study of predictors of bone metastasis in colorectal cancer patients

BACKGROUND: We explored risk factors for bone metastasis (BMs) in colorectal cancer (CRC) to improve in early diagnosis and follow-up and to reduce bone metastasis. METHODS: With a retrospective analysis of 2066 patients with CRC treated in our institution from January 2006 to January 2015, we assessed high-risk variables associated with bone metastasis using univariate and multivariate analyses. RESULTS: Of those subjects studied, 102 patients developed BMs, including 62 of 1014 the rectal cancer patients and 40 of the 1052 colon cancer patients. Lung metastases were accounting for 59.8% of the BMs (χ(2) = 17.7, p<0.01) and hepatic metastases were accounting for 34.3% of BMs (χ(2) = 3.06,p >0.05). BMs were diagnosed more rapidly in the presence of lung metastases(6.9 months versus 11.6 months for liver metastases). Univariate analysis revealed that BMs were associated with primary tumor location (p < 0.001), lung metastases (p < 0.001), initial stage (p = 0.001), radiotherapy (p < 0.001) and serum carcinoembryonic antigen (CEA) (p=0.001). Multivariate analysis revealed that primary tumor location (rectum), lung metastases, and serum CEA (>5 μg/L) were statistically significant (p <0.05). CONCLUSIONS: BMs in rectal cancer occur more frequently than in colon cancer. Lung metastases predicted potential progression to bone in CRCs more than liver metastases. Primary rectal locations, lung metastases and serum CEA were independent risk factors for BMs in CRC. Thus, patients should receive early bones scanning when presenting with CRC.