Histomorphometric and microarchitectural analyses using the 2 mm bone marrow trephine in metastatic breast cancer patients-preliminary results

Histomorphometric and microarchitectural analysis of bone in metastatic breast cancer patients

BACKGROUND

Despite widespread use of repeated doses of potent bone-targeting agents (BTA) in oncology patients, relatively little is known about their in vivo effects on bone homeostasis, bone quality, and bone architecture. Traditionally bone quality has been assessed using a trans-iliac bone biopsy with a 7 mm "Bordier" core needle. We examined the feasibility of using a 2 mm "Jamshidi™" core needle as a more practical and less invasive technique.

METHODS

Patients with metastatic breast cancer on BTAs were divided according to the extent of bone metastases. They were given 2 courses of tetracycline labeling and then underwent a posterior trans-iliac trephine biopsy and bone marrow aspirate. Samples were analyzed for the extent of tumor invasion and parameters of bone turnover and bone formation by histomorphometry.

RESULTS

Twelve patients were accrued, 1 had no bone metastases, 3 had limited bone metastases (LSM) (<3 lesions) and 7 had extensive bone metastases (ESM) (>3 lesions). Most of the primary tumors were estrogen receptor (ER)/progesterone receptor (PR) positive. The procedure was well tolerated. The sample quality was sufficient to analyze bone trabecular structure and bone turnover by histomorphometry in 11 out of 12 patients. There was a good correlation between imaging data and morphometric analysis of tumor invasion. Patients with no evidence or minimal bone metastases had no evidence of tumor invasion. Most had suppressed bone turnover and no detectable bone formation when treated with BTA. In contrast, 6 out of 7 patients with extensive bone invasion by imaging and evidence of tumor cells in the marrow had intense osteoclastic activity as measured by the number of osteoclasts. Of these 7 patients with ESM, 6 were treated with BTA with 5 showing resistance to BTA as demonstrated by the high number of osteoclasts present. 3 of these 6 patients had active bone formation. Based on osteoblast activity and bone formation, 3 out of 6 patients with ESM responded to BTA compared to all 3 with LSM. Compared to untreated patients, all patients treated with BTA showed a trend towards suppression of bone formation, as measured by tetracycline labelling. There was also a trend towards a significant difference between ESM and LSM treated with BTA, highly suggestive of resistance although limited by the small sample size.

DISCUSSION

Our results indicate that trans-iliac bone biopsy using a 2 mm trephine shows excellent correlation between imaging assessment of tumor invasion and tumor burden by morphometric analysis of bone tissues. In addition, our approach provides additional mechanistic information on therapeutic response to BTA supporting the current clinical understanding that the majority of patients with extensive bone involvement eventually fail to suppress bone turnover (Petrut B, et al. 2008). This suggests that antiresorptive therapies become less effective as disease progresses.

Strategies for obtaining bone biopsy specimens from breast cancer patients - Past experience and future directions

Background

Cancer and its treatment can have multiple effects on the bone. Despite the widespread use of in vivo and in vitro models, it is still necessary to understand these effects in humans. Obtaining human bone biopsies is technically challenging and in this article we review the experiences from the Ottawa Bone Oncology Program.

Methods

A series of bone biopsy studies in breast cancer patients with and without bone metastasis have been performed. We reviewed the results of these studies and present them in a descriptive manner. We discuss lessons learned from each project and how they have affected future directions for research.

Results

Since 2009, 5 studies have been performed accruing 97 breast cancer patients. Study endpoints have ranged from comparing the yield of malignant cells from CT-guided versus standard iliac crest biopsies, to studies assessing the feasibility of micro-CT analysis on Jedhadi trephines to evaluate bisphosphonate effects on bone micro-architecture. More recently, we have assessed the feasibility of performing repeat bone biopsies in the same patient as well as evaluating the practicality of obtaining bone tissue at the time of orthopaedic surgery.

Conclusion

Human bone tissue is an important biological resource. Our experience suggests that obtaining bone biopsies is feasible and can yield adequate amount of tumour cells for many studies. However, these remain technically challenging specimens to obtain and given the rapid advances in cancer therapeutics and the use of potent adjuvant bone-targeted agents, more centres need to be involved in these types of studies.

Are adjuvant bisphosphonates now standard of care of women with early stage breast cancer? A debate from the Canadian Bone and the Oncologist New Updates meeting

The 9th Bone and the Oncologist New Updates conference was held in Ottawa, Canada during 2014. This annual meeting focuses on innovative research into the mechanisms and consequences of treatment-induced and metastatic bone disease. Given the recent presentation of the Oxford overview's “Effects of bisphosphonate treatment on recurrence and cause-specific mortality in women with early breast cancer: A meta-analysis of individual patient data from randomized trials” at the San Antonio Breast Cancer Symposium, a debate as to the pro's and con's of adjuvant bisphosphonate use in early stage breast cancer was undertaken. As bisphosphonate treatment in post-menopausal women appeared to demonstrate a similar magnitude of benefit to that of other commonly used adjuvant strategies the debate assessed whether or not there was sufficient data to incorporate adjuvant bisphosphonates into standard practice and if so, in which patient populations.

Bone-targeted therapy for metastatic breast cancer-Where do we go from here? A commentary from the BONUS 8 meeting

The annual Bone and The Oncologist New Updates (BONUS 8) conference focuses on the current understanding and dilemmas in the treatment and prevention of bone metastasis in cancer, as well as novel research on bone homeostasis and cancer-induced bone loss. We present commentaries from experts for their own take on where they feel the field of bone-targeted therapies for metastatic breast cancer is moving, or needs to move, if we are to make further progress.

Bone-Targeted Agents for the Management of Breast Cancer Patients with Bone Metastases

Despite advances in adjuvant therapy for breast cancer, bone remains the most common site of recurrence. The goal of therapy for these patients is palliative and focused on maximizing the duration and quality of their life, while concurrently minimizing any disease or treatment-related complications. Bone metastases predispose patients to reduced survival, pain, impaired quality of life and the development of skeletal-related events. With an increased understanding of the pathophysiology of bone metastasis, effective treatments for their management have evolved and are now in widespread clinical use. This article will discuss the pathogenesis of bone metastases and review the key clinical evidence for the efficacy and safety of currently available systemic bone-targeted therapies in breast cancer patients with an emphasis on bisphosphonates and the receptor activator of nuclear factor kappa B ligand (RANKL) inhibitors. We will also discuss novel strategies and therapies currently in development.