Prospective Identification of Risk Factors for Skeletal Related Events in Breast Cancer Patients Receiving Bisphosphonates for Bone Metastases

Official Title

Prospective Identification of Risk Factors for Skeletal Related Events in Breast Cancer Patients Receiving Bisphosphonates for Bone Metastases


Breast Cancer is the most commonly diagnosed cancer in women in North America.  Despite effective therapies, many women develop metastatic disease (ie disease that has spread outside of the breast to other parts of the body).  For these women, the goal of care is to improve quality of life and, where possible, prolong quantity of life. The most common site of metastatic disease is spread to the bone.  Bone metastases can significantly affect patients quality of life by causing pain, fractures, spinal cord compression, and life-threatening biochemical abnormalities (high calcium in the blood).  Bisphosphonate drugs are medications that have been proven to decrease the frequency of these events.  At present, however, the best way to deliver these drugs is not known.  We aim to develop a risk score for women with bone metastases, so that we can stratify women into low, medium, and high risk categories.  This will allow us to tailor treatment for bone metastases based on risk category.

Trial Description

This is an exploratory study to develop a prognostic model for development of skeletal related events (SREs).  Once the most important features that predict for SREs are found from this exploratory study, we plan to validate the model in a larger cohort of patients.  This study will prospectively determine whether bone density, bone quality, and/or markers of bone breakdown are helpful in risk stratifying the SRE rate in patients who have metastatic breast cancer to bone.

Using a prospective, observational trial design, we will develop a prognostic model with baseline sCTX as the predictor variable and SREs as the outcome variable.  Baseline characteristics of patients (and potential risk factors) will be recorded upon their enrollment including clinical factors (prior fragility fracture, use of corticosteroids, age), bone mineral density, performance status, measures of quality of life and pain, and novel markers such as serum C-telopeptide (sCTX) (a marker of bone breakdown) and bone specific alkaline phosphatase (bALP) (a marker of bone formation).  In addition, bone mineral density and assessment of vertebral fractures will take place using a novel technique, bone densitometric vertebral fracture assessment (VFA), and bone quality will be assessed with high resolution partially quantitative CT (HRpQCT) at baseline, one year, and two years.  Patients will be assessed every twelve weeks for twenty-four months with regards to: symptoms related to SREs, performance status, pain, and quality of life.  Serum will be taken every twelve weeks for twenty-four months (5x/year x 2 years) in order to measure bALP, and sCTX.Serum and urine will also be taken at these timepoints and banked for use in future research studies (consent for this will be obtained with the standard UHN consent for future use of blood and body fluid)- these studies may include correlation of urine NTx with serum CTx, and use of PTHrP as a prognostic marker.

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Canadian Cancer Society

These resources are provided in partnership with the Canadian Cancer Society