Bone metastasis from colorectal cancer (CRC) is known as poor prognostic factor. However, the clinical manifestations and outcomes of CRC with bone metastasis are uncertain.
CRC with bone metastasis were searched from January 2006 to April 2016, and bone metastasis was diagnosed by plain x-ray, computed tomography (CT), magnetic resonance image (MRI), whole body bone scan (WBBS) or positron emission tomography (PET). Clinical data including site of bone metastasis, visceral metastasis, laboratory finding at diagnosis of bone metastasis, and K-ras mutation were reviewed. Time to event endpoint was analyzed by Kaplan-Meier survival curves for overall survival (OS).
Of 12,005 CRC patients, 321 (2.7%) had bone metastasis. Colon cancer (58.5%) is more than rectal cancer (41.5%), and pattern of metachronous bone metastasis was 166 (51.7%). Median time to bone metastasis was 28.2 months from diagnosis of CRC in metachronous patients. The most common bone metastasis site was spine (69.5%) and followed by pelvis (52.1%) and long bone (21.6%). At the time of bone metastasis, liver (58.2%), lung (51.5%) and peritoneal (23.8%) metastasis was also observed, and bone only metastasis was 28 (8.5%) patients. High neutrophil-lymphocyte ratio (NLR, ≥3.0), alkaline phosphatase (ALP, ≥123 IU/L) and carcinoembryonic antigen (CEA, ≥5 ng/mL) had significantly correlated with bone only metastasis at a low frequency. Median OS from diagnosis of bone metastasis was 8.0 months (95% CI = 6.8-9.2). Patients with bone only metastasis had longer OS (median OS, 19.1 vs. 7.6 months, P
Bone metastasis of CRC is not a rare event and has a poor prognosis. Bone only metastasis is the most significant prognostic factor and further studies are needed.
Clinical trial identification
Legal entity responsible for the study
Yonsei Cancer Center, Yonsei University Health System
All authors have declared no conflicts of interest.