283P - Comparative analysis of osteoporotic fracture (OF) and pathologic fracture (PF) in patients with metastatic colorectal cancer (mCRC) who received palliative chemotherapy

Background

Bone fracture is a devastating event in patients with mCRC. Nevertheless, no study has compared OF and PF in these patients.

Methods

We retrospectively analyzed clinical data of patients with mCRC who underwent palliative first-line oxaliplatin or irinotecan backbone chemotherapy at Seoul National University Bundang Hospital. This study aimed to identify the cumulative incidence rates of OF and PF in these patients and their risk factors.

Results

A total of 622 patients (male, 359) were consecutively enrolled between Jan. 2008 and Dec. 2015. The median age was 61 years (range, 20-91 years). Before palliative first-line chemotherapy (oxaliplatin backbone and irinotecan backbone in 313 [50.3%] and 309 [49.7%] patients, respectively), the median body mass index was 22.6 kg/m² (range, 13.8-36.2 kg/m²) and bone metastasis was found in 42 patients (6.8%). During a median follow-up of 65.5 months (range 1.6-126.0 months), the median overall survival was 27.2 months (95% confidence interval [CI], 24.5-29.9 months). Among 81 patients (13.0%) who experienced OF or PF events, OF, PF, and both developed in 42 (6.8%), 36 (5.8%), and 3 (0.5%) patients, respectively. The cumulative incidence rates of OF and PF were 3.4% (95% CI, 2.2-5.0%) and 2.7% (95% CI, 1.7-4.3%) at 1 year, 4.5% (95% CI, 3.1-6.4%) and 4.2% (95% CI, 2.8-6.0%) at 2 years, and 5.6% (95% CI, 3.9-7.6%) and 5.1% (95% CI, 3.5-7.0%) at 3 years, respectively. The cumulative incidence rate of the first OF or PF was 6.0% (95% CI, 4.3-8.0%) at 1 year, 8.6% (95% CI, 6.6-11.0) at 2 years, and 10.4% (95% CI, 8.2-13.0%) at 3 years. The most common fracture sites were the lumbar spines (52.4%) in OF and the thoracic spines (50.0%) in PF, respectively. The OF risk was significantly higher in patients with age ≥ 65 years (hazard ratio [HR] 3.20 [95% CI, 1.73-5.92], p<0.001) while the PF risk was not significant between the age groups (HR 0.77 [95% CI, 0.40-1.49], p=0.430).

Conclusions

Fracture events were substantial in patients with mCRC who received palliative chemotherapy. Notably, the incidence of OF was comparable with that of PF. Therefore, OF should be considered in elderly patients with lumbar spine fractures.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.