Bisphosphonate treatment and radiotherapy in metastatic breast cancer

Bone density as a marker for local response to radiotherapy of spinal bone metastases in women with breast cancer: a retrospective analysis

BACKGROUND

We designed this study to quantify the effects of radiotherapy (RT) on bone density as a local response in spinal bone metastases of women with breast cancer and, secondly, to establish bone density as an accurate and reproducible marker for assessment of local response to RT in spinal bone metastases.

METHODS

We retrospectively assessed 135 osteolytic spinal metastases in 115 women with metastatic breast cancer treated at our department between January 2000 and January 2012. Primary endpoint was to compare bone density in the bone metastases before, 3 months after and 6 months after RT. Bone density was measured in Hounsfield units (HU) in computed tomography scans. We calculated mean values in HU and the standard deviation (SD) as a measurement of bone density before, 3 months and 6 months after RT. T-test was used for statistical analysis of difference in bone density as well as for univariate analysis of prognostic factors for difference in bone density 3 and 6 months after RT.

RESULTS

Mean bone density was 194.8 HU ± SD 123.0 at baseline. Bone density increased significantly by a mean of 145.8 HU ± SD 139.4 after 3 months (p = .0001) and by 250.3 HU ± SD 147.1 after 6 months (p < .0001). Women receiving bisphosphonates showed a tendency towards higher increase in bone density in the metastases after 3 months (152.6 HU ± SD 141.9 vs. 76.0 HU ± SD 86.1; p = .069) and pathological fractures before RT were associated with a significantly higher increase in bone density after 3 months (202.3 HU ± SD 161.9 vs. 130.3 HU ± SD 129.2; p = .013). Concomitant chemotherapy (ChT) or endocrine therapy (ET), hormone receptor status, performance score, applied overall RT dose and prescription of a surgical corset did not correlate with a difference in bone density after RT.

CONCLUSIONS

Bone density measurement in HU is a practicable and reproducible method for assessment of local RT response in osteolytic metastases in breast cancer. Our analysis demonstrated an excellent local response within metastases after palliative RT.

Effects of zoledronate on the radiation-induced collagen breakdown: a prospective randomized clinical trial

BACKGROUND

A negative side effect of therapeutic irradiation is the radiation-induced bone loss which can lead, in long term, to pathological fractures. Until today, the detailed mechanism is unknown. If osteoclasts would mainly contribute to the pathological bone loss, bisphosphonates could potentially counteract the osteolytic process and possibly help to prevent long-term complications. The aim of this study was to evaluate the effect of zoledronic acid on the early radiation-induced degradation of bone collagen fibrils by monitoring the urinary excretion of hydroxylysylpyridinoline and lysylpyridinoline under radiotherapy.

PATIENTS AND METHODS

A total of 40 patients with skeletal metastases were assigned for a local radiotherapy and bisphosphonate treatment. The patients were prospectively randomized into two treatment groups: group A (n = 20) received the first zoledronate administration after and group B (n = 20) prior to the radiotherapy. Urine samples were collected from each patient on the first day, in the middle, and on the last day of the radiation therapy. Measurement of the bone metabolites hydroxylysylpyridinoline and lysylpyridinoline was performed by high-performance liquid chromatography. Statistical analysis was performed using the Mann-Whitney U test.

RESULTS

The hydroxylysylpyridinoline and lysylpyridinoline excretion decreased significantly in the combined bisphosphonate and radiotherapy group (p = 0.02, p = 0.08). No significant change of the hydroxylysylpyridinoline and lysylpyridinoline excretion was determined in the patients that received solely irradiation.

CONCLUSION

The results indicate the ability of zoledronate to prevent the early radiation-induced bone collagen degradation suggesting that the radiation-induced bone loss is mainly caused by osteoclastic bone resorption rather than by a direct radiation-induced damage.

FemZone trial: a randomized phase II trial comparing neoadjuvant letrozole and zoledronic acid with letrozole in primary breast cancer patients

BACKGROUND

The objective of this prospectively randomized phase II trial (Trial registration: EUCTR2004-004007-37-DE) was to compare the clinical response of primary breast cancer patients to neoadjuvant therapy with letrozole alone (LET) or letrozole and zoledronic acid (LET + ZOL).

METHODS

Patients were randomly assigned to receive either LET 2.5 mg/day (n = 79) or the combination of LET 2.5 mg/day and a total of seven infusions of ZOL 4 mg every 4 weeks (n = 89) for 6 months. Primary endpoint was clinical response rate as assessed by mammogram readings. The study was terminated prematurely due to insufficient recruitment. We report here on an exploratory analysis of this data.

RESULTS

Central assessment of tumor sizes during the treatment period was available for 131 patients (66 LET, 65 LET + ZOL). Clinical responses (complete or partial) were seen in 54.5% (95% CI: 41.8-66.9) of the patients in the LET arm and 69.2% (95% CI: 56.6-80.1) of those in the LET + ZOL arm (P = 0.106). A multivariate model showed an OR of 1.72 (95% CI: 0.83-3.59) for the experimental arm.

CONCLUSION

No increase in the clinical response rate was observed with the addition of ZOL to a neoadjuvant treatment regimen with LET. However a trend towards a better reponse in the LET + ZOL arm could be observed. This trend is consistent with previous studies that have investigated the addition of ZOL to chemotherapy, and it may support the evidence for a direct antitumor action of zoledronic acid.

Symptom management in metastatic breast cancer

Approximately 40,000 women die as a result of breast cancer each year and many more live with advanced disease. When breast cancer recurs, the goals of treatment often shift from one of cure to controlling the disease for as long as possible while palliating symptoms interfering with the patient's functional status and quality of life. This requires ongoing discussions with the patient and family about the goals of care. Many symptoms depend on the site of metastasis, with bone being the most frequent, and commonly occur with fatigue, depression, insomnia, and pain. The purpose of this paper is to identify and provide an overview of the management of the most common symptoms in patients with breast cancer metastases.

Optimal management of bone metastases in breast cancer patients

Bone metastasis in breast cancer is a significant clinical problem. It not only indicates incurable disease with a guarded prognosis, but is also associated with skeletal-related morbidities including bone pain, pathological fractures, spinal cord compression, and hypercalcemia. In recent years, the mechanism of bone metastasis has been further elucidated. Bone metastasis involves a vicious cycle of close interaction between the tumor and the bone microenvironment. In patients with bone metastases, the goal of management is to prevent further skeletal-related events, manage complications, reduce bone pain, and improve quality of life. Bisphosphonates are a proven therapy for the above indications. Recently, a drug of a different class, the RANK ligand antibody, denosumab, has been shown to reduce skeletal-related events more than the bisphosphonate, zoledronic acid. Other strategies of clinical value may include surgery, radiotherapy, radiopharmaceuticals, and, of course, effective systemic therapy. In early breast cancer, bisphosphonates may have an antitumor effect and prevent both bone and non-bone metastases. Whilst two important Phase III trials with conflicting results have led to controversy in this topic, final results from these and other key Phase III trials must still be awaited before a firm conclusion can be drawn about the use of bisphosphonates in this setting. Advances in bone markers, predictive biomarkers, multi-imaging modalities, and the introduction of novel agents have ushered in a new era of proactive management for bone metastases in breast cancer.

Identification of brain- and bone-specific breast cancer metastasis genes

In breast cancer, metastases are relatively widely distributed, with the most common sites being bone, regional lymph nodes, lung, liver, and brain. The detailed mechanism of organ-specific metastasis is poorly understood. In this study, we initiated a search for genes that are implicated in brain or bone metastasis of primary human breast cancer. We generated gene expression profiles of 18 brain and eight bone metastases derived from primary breast tumors. We identified 73 genes differentially expressed between brain and bone metastases. Visualization of the differential gene expression profiles by correspondence and cluster analyses shows that the metastases clearly separate into two distinct groups as an exact reflection of their site of metastasis. Moreover, the analysis of this gene set in primary breast tumors relapsing to either bone or brain allowed accurate categorization of the tumors according to their metastatic site. The identified genes may prove to be excellent markers to predict the site of metastasis in breast cancer patients and could lead to tailor-made therapy to an individual patient.