Abstract
In metastatic colorectal cancer (mCRC) patients, the incidence rate of osteoporotic fracture (OF) was comparable to that of pathologic fracture (4.5% vs 4.2% over 2 years), and even higher in those aged ≥ 70. Because age and osteoporosis are significant risk factors, assessing osteoporosis is critical to prevent OF in older mCRC patients. PURPOSE: Fractures in patients with metastatic colorectal cancer (mCRC) have been reported; however, most of these are pathologic fractures (PFs). This study aimed to identify the incidence rates of and risk factors for osteoporotic fracture (OF) and PF. METHODS: We retrospectively analyzed the clinical data of mCRC patients who received palliative chemotherapy. RESULTS: We enrolled 622 patients (359 male) consecutively. The median patient age was 61 (range, 20-91) years. Before chemotherapy, 42 (6.8%) patients had bone metastases. During follow-up, 86 (13.8%) patients experienced 96 fracture events. The cumulative incidence rates over the 2-year period were 4.5% (95% confidence interval [CI], 2.9-6.1%) and 4.2% (95% CI, 2.6-5.8%) for OF and PF, respectively. The crude incidence rate of OF was higher than that of PF in patients aged ≥ 70 years with an incidence rate ratio of 4.65 (95% CI, 1.72-15.7). Multivariable analysis identified older age (hazard ratio [HR], 1.04 [95% CI, 1.00-1.08]; p = 0.03) and osteoporosis (HR, 4.79 [95% CI, 1.51-15.16]; p = 0.01) as significant risk factors for OF after adjustment for bone and cancer-related variables. For PF, bone metastasis was a significant risk factor (HR, 9.48 [95% CI, 4.02-22.38]; p < 0.01). CONCLUSIONS: The incidence rate of OF was comparable to that of PF and even higher in mCRC patients aged ≥ 70 years. While bone metastasis was a risk factor for PF, advanced age and osteoporosis were the risk factors for OF. Therefore, osteoporosis assessment and treatment are crucial to prevent OF during chemotherapy, particularly in the elderly.