Evaluation of the prognosis of cancer patients with metastatic bone tumors based on serial bone scintigrams

Should the Use of Biologic Agents in Patients With Renal and Lung Cancer Affect Our Surgical Management of Femoral Metastases?

BACKGROUND

Biologic agents may prolong survival of patients with certain kidney and lung adenocarcinomas that have metastasized to bone, and patient response to these agents should be considered when choosing between an endoprosthesis and internal fixation for surgical treatment of femoral metastases.

QUESTIONS/PURPOSES

Among patients undergoing surgery for femoral metastases of lung or renal cell carcinoma, (1) Does survival differ between patients who receive only cytotoxic chemotherapy and those who either respond or do not respond to biologic therapy? (2) Does postsurgical incidence of local disease progression differ between groups stratified by systemic treatment and response? (3) Does implant survival differ among groups stratified by systemic treatment and response?

METHODS

From our institutional longitudinally maintained orthopaedic database, patients were identified by a query initially identifying all patients who carried a diagnosis of renal cell carcinoma or lung carcinoma. Patients who underwent internal fixation or prosthetic reconstruction between 2000 and 2016 for pathologic fracture of the femur and who survived ≥ 1 year after surgery were studied. Patients who received either traditional cytotoxic chemotherapy or a biologic agent were included. Patients were classified as responders or nonresponders to biologic agents based on whether they had clinical and imaging evidence of a response recorded on two consecutive office visits over ≥ 6 months. Endpoints were overall survival from the time of diagnosis, survival after the femoral operation, evidence of disease progression in the femoral operative site, and symptomatic local disease progression for which revision surgery was necessary. Our analysis included 148 patients with renal (n = 26) and lung (n = 122) adenocarcinoma. Fifty-one patients received traditional chemotherapy only. Of 97 patients who received a biologic agent, 41 achieved a response (stabilization/regression of visceral metastases), whereas 56 developed disease progression. We analyzed overall patient survival with the Kaplan-Meier method and used the log-rank test to identify significant differences (p < 0.05) between groups.

RESULTS

One-year survival after surgery among patients responsive to biologic therapy was 61% compared with 20% among patients nonresponsive to biologics (p < 0.001) and 10% among those who received chemotherapy only (p < 0.009). With the number of patients we had to study, we could not detect any difference in local progression of femoral disease associated with systemic treatment and response. Radiologic evidence of periimplant local disease progression developed in three (7%) of 41 patients who responded to biologic treatment, two (3%) of 56 patients nonresponsive to biologics, and one (2%) of 51 patients treated with traditional chemotherapy. With the numbers of patients we had, we could not detect a difference in patients who underwent revision. All three patients responsive to biologics who developed local recurrence underwent revision, whereas the two without a response to biologics did not.

CONCLUSIONS

Biologic therapy improves the overall longevity of some patients with lung and renal metastases to the femur in whom a visceral disease response occurred. In our limited cohort, we could not demonstrate an implant survival difference between such patients and those with shorter survival who may have had more aggressive disease. However, an increased life expectancy beyond 1 year among patients responsive to biologics may increase risk of mechanical failure of fixation constructs.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Biomechanical effects of metastasis in the osteoporotic lumbar spine: A Finite Element Analysis

BACKGROUND

Cancer patients are likely to undergo osteoporosis as consequence of hormone manipulation and/or chemotherapy. Little is known about possible increased risk of fracture in this population. The aim of this study was to describe the biomechanical effect of a metastatic lesion in an osteoporotic lumbar spine model.

METHODS

A finite element model of two spinal motion segments (L3-L5) was extracted from a previously developed L3-Sacrum model and used to analyze the effect of metastasis size and bone mineral density (BMD) on Vertebral bulge (VB) and Vertebral height (VH). VB and VH represent respectively radial and axial displacement and they have been correlated to burst fracture. A total of 6 scenarios were evaluated combining three metastasis sizes (no metastasis, 15% and 30% of the vertebral body) and two BMD conditions (normal BMD and osteoporosis).

RESULTS

15% metastasis increased VB and VH by 178% and 248%, respectively in normal BMD model; while VB and VH increased by 134% and 174% in osteoporotic model. 30% metastasis increased VB and VH by 88% and 109%, respectively, when compared to 15% metastasis in normal BMD model; while VB and VH increased by 59% and 74% in osteoporotic model.

CONCLUSION

A metastasis in the osteoporotic lumbar spine always leads to a higher risk of vertebral fracture. This risk increases with the size of the metastasis. Unexpectedly, an increment in metastasis size in the normal BMD spine produces a greater impact on vertebral stability compared to the osteoporotic spine.

High circulating tumor cell concentrations in a specific subtype of gastric cancer with diffuse bone metastasis at diagnosis

AIM: To clarify the biological feature contributing to gastric cancer with diffuse bone metastases at diagnosis.

METHODS: The participants visited the Department of Clinical Oncology, Akita University Hospital, from January 2014 to August 2015. The selection criterion for gastric cancer with diffuse bone metastases at diagnosis includes over 29 hot spots of bone scintigraphy. Circulating tumor cell were collected from 20 mL of peripheral venous blood drawn using a CellSearch kit and a CellTracks AutoPrep system by SRL, a clinical laboratory. The endpoints of this study were correlations between circulating tumor cells (CTC) count and therapeutic outcomes.

RESULTS: Among 39 patients with gastric cancer, 5 patients met the criterion. The incidence of this subtype was 12.8%. CTC counts ranged from 235 to 6440 cells/7.5 mL of peripheral blood (median of 1724). These values were much higher than common gastric cancers (2 cells). In chemo-sensitive cases, CTC counts decreased within 14 d (median) from 275, 235 and 1724 to 2, 7 and 66, respectively. On the other hand, CTC counts increased after treatment failure or insensitive case from 2, 7 and 6440 to 787, 513 and 7885, respectively. The correlation between CTC count and survival time showed a trend, but did not reach significance (Y = 234.6 - 0.03X, P = 0.085).

CONCLUSION: High CTC count is a biological hallmark of this subtype, and can be used as a direct and definitive indicator of therapeutic outcome.

Healthcare costs associated with skeletal-related events in breast cancer patients with bone metastases

BACKGROUND

Patients with bone metastases secondary to breast cancer are pre-disposed to skeletal-related events (SREs), including spinal cord compression (SCC), pathologic fracture (PF), surgery to bone (SB), and radiotherapy to bone (RT).

OBJECTIVE

To document current patterns of healthcare utilization and costs of SREs in patients with breast cancer and bone metastases.

METHODS

This was a retrospective, observational study using the Thomson MedStat MarketScan Commercial Claims and Encounters database from 9/2002 to 6/2011. Study subjects included all persons with claims for breast cancer and for bone metastases, and ≥1 claims for an SRE. Unique SRE episodes were identified based on a gap of at least 90 days without an SRE claim, and classified by treatment setting (inpatient or outpatient) and SRE type (SCC, PF, SB, or RT).

RESULTS

Of 17,266 patients with breast cancer and bone metastases, 9142 (53%) had one or more SRE episodes. Among 5809 patients who met all other criteria, there were 7617 SRE episodes over mean (SD) follow-up of 17.2 (15.2) months. The percentage of episodes that required inpatient treatment ranged from 11% (RT) to 76% (SB). On average, inpatient SCC episodes (n=83 episodes) were most costly; while outpatient PF episodes (n=552 episodes) were least costly. Of the total SRE costs (mean [SE] $21,072 [$36,462]/episode), 36% were attributable to outpatient RT (n=5265 episodes) and 31% to inpatient PF (n=838 episodes).

LIMITATIONS

The administrative claims data used in this study may lack sensitivity and specificity for identification of clinical events and may not be generalizable to other populations. Also, for some SRE episode categories, the number of events was small and cost estimates may lack precision.

CONCLUSION

In patients with breast cancer and bone metastases, SREs are associated with high costs and hospitalizations.

When to perform positron emission tomography/computed tomography or radionuclide bone scan in patients with recently diagnosed prostate cancer

Skeletal metastases are very common in prostate cancer and represent the main metastatic site in about 80% of prostate cancer patients, with a significant impact in patients’ prognosis. Early detection of bone metastases is critical in the management of patients with recently diagnosed high-risk prostate cancer: radical treatment is recommended in case of localized disease; systemic therapy should be preferred in patients with distant secondary disease. Bone scintigraphy using radiolabeled bisphosphonates is of great importance in the management of these patients; however, its main drawback is its low overall accuracy, due to the nonspecific uptake in sites of increased bone turnover. Positron-emitting radiopharmaceuticals, such as fluorine-18-fluorodeoxyglucose, choline-derived drugs (fluorine-18-fluorocholine and carbon-11-choline) and sodium fluorine-18-fluoride, are increasingly used in clinical practice to detect metastatic spread, and particularly bone involvement, in patients with prostate cancer, to reinforce or substitute information provided by bone scan. Each radiopharmaceutical has a specific mechanism of uptake; therefore, diagnostic performances may differ from one radiopharmaceutical to another on the same lesions, as demonstrated in the literature, with variable sensitivity, specificity, and overall accuracy values in the same patients. Whether bone scintigraphy can be substituted by these new methods is a matter of debate. However, greater radiobiological burden, higher costs, and the necessity of an in-site cyclotron limit the use of these positron emission tomography methods as first-line investigations in patients with prostate cancer: bone scintigraphy remains the mainstay for the detection of bone metastases in current clinical practice.

Skeletal metastases - the role of the orthopaedic and spinal surgeon

Developments in oncological and medical therapies mean that life expectancy of patients with metastatic bone disease (MBD) is often measured in years. Complications of MBD may dramatically and irreversibly affect patient quality of life, making the careful assessment and appropriate management of these patients essential. The roles of orthopaedic and spinal surgeons in MBD generally fall into one of four categories: diagnostic, the prophylactic fixation of metastatic deposits at risk of impending fracture (preventative surgery), the stabilisation or reconstruction of bones affected by pathological fractures (reactive surgery), or the decompression and stabilisation of the vertebral column, spinal cord, and nerve roots. Several key principals should be adhered to whenever operating on skeletal metastases. Discussions should be held early with an appropriate multi-disciplinary team prior to intervention. Detailed pre-assessment is essential to gauge a patient's suitability for surgery - recovery from elective surgery must be shorter than the anticipated survival. Staging and biopsies provide prognostic information. Primary bone tumours must be ruled out in the case of a solitary bone lesion to avoid inappropriate intervention. Prophylactic surgical fixation of a lesion prior to a pathological fracture reduces morbidity and length of hospital stay. Regardless of a lesion or pathological fracture's location, all regions of the affected bone must be addressed, to reduce the risk of subsequent fracture. Surgical implants should allow full weight bearing or return to function immediately. Post-operative radiotherapy should be utilised in all cases to minimise disease progression. Spinal surgery should be considered for those with spinal pain due to potentially reversible spinal instability or neurological compromise. The opinion of a spinal surgeon should be sought early, as delays in referral directly correlate to worse functional recovery following intervention. Patients who suffer a slowly progressive deficit, present within hours of complete neurological deficit, or have compression caused by bone alone are those most likely to benefit from surgery. Back pain in the presence of MBD should be regarded as impending spinal cord compression, and investigated urgently to allow intervention prior to the development of neurological compromise.

Anterior construct location following vertebral body metastasis reconstruction through a posterolateral transpedicular approach: does it matter?

Object

The posterolateral transpedicular approach (PTA) is a widely used method for the surgical treatment of vertebral body metastases. It is crucial to understand the optimal location of the anterior graft in terms of sound and durable reconstruction following PTA. The purpose of this study was to investigate whether postoperative construct stability is related to the location of anterior grafts.

Methods

The authors conducted a retrospective review of 45 cases of metastatic spine disease with epidural tumor extension in which patients underwent circumferential decompression and fusion by means of PTA. Mechanical (anterior construct stability), pain (visual analog scale score), and neurological (American Spinal Injury Association scale) outcomes were evaluated and correlated with the anterior graft location (lateral or central) and surgical approach (unilateral or bilateral), number of decompressed levels, types of anterior graft, screw density of posterior fixation (number of screws used divided by the number of pedicles spanned), and kyphotic angle change from the immediate postoperative period to the most recent follow-up.

Results

Seven of 45 constructs were judged unstable—5 with a lateral location of the anterior graft and 2 with a central location.

The anterior graft was located laterally in 31 cases (69%), centrally in 11 (24%), and bilaterally in 3 (7%). A unilateral approach was used in 33 cases and a bilateral approach in 12. Neither the location of the anterior graft nor the approach had a significant effect on the stability of the reconstructed spine (p > 0.05). There was a significant difference in construct stability between the single-level decompression group (33 patients) and the multiple-level decompression group (12 patients) (p = 0.0001). The types of anterior graft, screw density, and kyphotic angle change were not correlated to the mechanical outcome.

Conclusions

The anterior graft location showed no significant relationship to the final mechanical, pain, and neurological outcomes.

A novel model of bone-metastatic prostate cancer in immunocompetent mice

BACKGROUND

Bone metastasis is a frequent and catastrophic consequence of prostate cancer for which only palliative treatment is available. Animal models of bone metastatic prostate cancer are necessary for understanding disease mechanisms but few models exist.

METHODS

We have used the murine prostate carcinoma cell line RM1 to generate a bone metastatic model of prostate cancer. Repeated intracardiac injection of RM1 cells followed by isolation of cells from bone tumors has yielded a cell line with strong bone-metastatic potential, RM1 bone metastatic (BM).

RESULTS

This cell line metastasizes to multiple bony sites in over 95% of injected C57BL/6 mice and is far less tropic to soft tissues. Bone tumors produced by the RM1(BM) cell line show no preference for particular skeletal sites as most bones are affected. Histology, and micro-computed tomography show that RM1(BM) cells form osteolytic tumors, but with evidence of osteoblastic changes. In vitro the RM1 cells express E-cadherin but not vimentin, do not form colonies in soft agar, are non-invasive but are more motile than the parent cell line.

CONCLUSIONS

This model provides a novel means for identifying cellular and molecular mechanisms that contribute to bone metastasis and allow for preclinical testing of therapies to prevent and treat tumor metastasis to bone. Finally as the syngeneic tumor cells are injected into immunocompetent mice, this model will provide a means to study interactions between the immune system, tumors and bone, and therapies that target such interactions.

The prostate: diagnostic evaluation of metastatic disease

One of the single most important considerations in clinical management of the patient with prostate cancer is whether or not metastatic disease is present. The identification of metastatic disease in a patient with newly diagnosed prostate cancer represents an absolute contraindication to definitive local therapies such as radial prostatectomy or radiation therapy. Similarly, the identification of metastatic disease in a patient with disease recurrence after definitive local therapy represents an absolute contraindication to salvage radiotherapy or cryosurgery. Patients with metastatic disease do not benefit from definitive therapy, and the cost and morbidity associated with such treatment should therefore be avoided in these patients. Because of the significance of metastatic disease to clinical management, it is important for the diagnostic radiologist to be aware of important considerations in the metastatic work-up of patients with newly diagnosed prostate cancer and patients with suspected cancer recurrence after definitive local therapy.