Bisphosphonates and bone metastases: current status and future directions

Development and validation of risk and prognostic nomograms for bone metastases in Chinese advanced colorectal cancer patients

Background

Bone metastases (BM) from colorectal cancer (CRC) are often accompanied by extraosseous metastases, resulting in a dismal prognosis. The present study aimed to determine the risk factors for BM in metastatic CRC (mCRC) and the prognostic factors for CRC patients with BM.

Methods

The study was based on a training cohort of 214 mCRC patients (of which, 101 patients had BM) from our center, and a validation cohort of 511 mCRC patients (of which, 173 patients had BM) from another institute. Risk and prognostic nomograms for BM were developed using univariate and multivariate analyses. The goodness of fit, discrimination, and calibration performance of the nomograms were assessed by R², concordance statistics (C-statistics), and the calibration curve. The results were internally validated using bootstrap resampling in the training cohort, and externally validated in the validation cohort.

Results

The novel BM risk nomogram comprised seven variables [degree of tumor differentiation, N-stage, serum alkaline phosphatase (ALP), lactate dehydrogenase (LDH), carcinoembryonic antigen (CEA), liver metastasis, and lung metastasis]. It showed good performance, with an R² of 0.447 and a C-statistic of 0.846 [95% confidence interval (CI), 0.793 to 0.898] in the training cohort, and an R² of 0.325 and a C-statistic of 0.792 (95% CI, 0.750 to 0.834) in the validation cohort. The optimal cutoff value to identify individuals at low or high risk was 56% probability, with a sensitivity of 71.3% and a specificity of 89.4%. The prognostic nomogram included five factors (tumor differentiation, number of extra-BM organs, number of BM lesions, ALP, and LDH), and had an R² of 0.284 and a C-statistic of 0.723 (95% CI, 0.657 to 0.789) in the training set. This nomogram was externally validated in the validation cohort, with an R² of 0.182 and a C-statistic of 0.682 (95% CI, 0.638 to 0.726).

Conclusions

The developed and validated risk and prognostic nomograms showed good performance for predicting the occurrence of BM in mCRC as well as the prognosis of CRC patients with BM. The risk nomogram can be used as a cost-effective preliminary screening tool prior to bone scanning.

Stability of Spinal Bone Metastases and Survival Analysis in Renal Cancer after Radiotherapy

Purpose

This retrospective analysis evaluated the outcome of patients with spinal bone metastases of renal cell cancer after radiotherapy (RT) in terms of stability and survival, using a validated scoring system for spinal stability assessment.

Materials and Methods

The survival rates of 155 patients with bone metastases of renal cancer treated from January 2000 to January 2012 were determined. The stability of irradiated osteolytic lesions of the thoracic and lumbar spine was evaluated retrospectively using the Taneichi score and analyzed for predictive factors. The effects of therapy in terms of changes in neurological signs and tumor-related pain were recorded.

Results

Follow-up with regular computed tomography (CT) was available for 28 patients, 14 with unstable metastases. One hundred thiry-two patients (85%) died during follow-up. RT could not improve the stability of vertebral bodies after 3 and 6 months. Consequently, none of the examined predictive factors such as age, number of bone metastases and systemic therapy showed a significant correlation with stability 6 months after RT. The median survival of all 155 patients after diagnosis of bone metastases was 12.9 months. Improvement of pain and neurological deficits occurred in 60%, and in 24% of the respective affected in all patients.

Conclusions

RT was unable to improve the stability of vertebral metastases, probably due to the short overall survival, which resulted in an insufficient number of patients with evaluable follow-up. RT allowed reduction of pain and neurological deficits. A short fractionation schedule may be preferred in this situation.

Viral infection in renal transplant recipients

Viruses are among the most common causes of opportunistic infection after transplantation. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or posttransplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections. This paper will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Osteoinductivity of demineralized bone matrix is independent of donor bisphosphonate use

BACKGROUND

Demineralized bone matrix is commonly used as a bone graft substitute, either alone or to supplement an osteoconductive material, because of its osteoinductive properties. The aging of the population has led to an increase in the number of prospective donors of demineralized bone matrix who have taken bisphosphonates to prevent osteoclast-mediated bone resorption. The aim of this study was to determine whether oral bisphosphonate usage affects the osteoinductivity of demineralized bone matrix from donors.

METHODS

Sex-matched and age-matched pairs of samples were provided by four tissue banks (three or four pairs per bank). Demineralized bone matrix donors without bisphosphonate treatment had a mean age (and standard deviation) of 69.1 ± 2.5 years, and donors with bisphosphonate treatment had a mean age of 68.9 ± 2.0 years. Each pair included one donor known to have taken bisphosphonates and one who had not taken bisphosphonates. Demineralized bone matrix previously confirmed as osteoinductive was the positive control, and heat-inactivated demineralized bone matrix was the negative control. Demineralized bone matrix incubated with 1 mL of phosphate-buffered saline solution containing 0, 0.002, 2.0, or 2000 ng/mL of alendronate was also tested. Gelatin capsules containing 15 mg of demineralized bone matrix were implanted bilaterally in the gastrocnemius muscle of male nude mice (eight implants per group). The mice were killed thirty-five days after implantation, and hind limbs were recovered and processed for histological analysis. Osteoinductivity was measured with use of a qualitative score and by histomorphometry.

RESULTS

Nine of fifteen samples from donors who had had bisphosphonate treatment and ten of fifteen samples from patients who had not had bisphosphonate treatment were osteoinductive. Qualitative mean scores were comparable (1.7 ± 0.4 for those without bisphosphonates and 1.9 ± 0.7 for those with bisphosphonates). Osteoinductive demineralized bone matrix samples produced ossicles of comparable size, regardless of bisphosphonate usage. Histomorphometric measurements of the area of new bone formation and residual demineralized bone matrix were also comparable. The addition of alendronate to control demineralized bone matrix did not affect its osteoinductivity.

CONCLUSIONS

Demineralized bone matrix samples from donors treated with bisphosphonates and donors not treated with bisphosphonates have the same ability to induce bone formation. However, it is not known if the quality of the new bone is affected, with subsequent consequences affecting bone remodeling.

Bone metastases: assessment of therapeutic response through radiological and nuclear medicine imaging modalities

Radiological and nuclear medicine imaging modalities used for assessing bone metastases treatment response include plain and digitalised radiography (XR), skeletal scintigraphy (SS), dual-energy X-ray absorptiometry (DEXA), computed tomography (CT), magnetic resonance imaging (MRI), [(18)F] fluorodeoxyglucose positron emission tomography (FDG-PET) and PET/CT. Here we discuss the advantages and disadvantages of these assessment modalities as evident through different clinical trials. Additionally, we present the more established response criteria of the International Union Against Cancer and the World Health Organization and compare them with newer MD Anderson criteria. Even though serial XR and SS have been used to assess the therapeutic response for decades, several months are required before changes are evident. Newer techniques, such as MRI or PET, may allow an earlier evaluation of response that may be quantified through monitoring changes in signal intensity and standard uptake value, respectively. Moreover, the application of PET/CT, which can follow both morphological and metabolic changes, has yielded interesting and promising results that give a new insight into the natural history of metastatic bone disease. However, only a few studies have investigated the application of these newer techniques and further clinical trials are needed to corroborate their promising results and establish the most suitable imaging parameters and evaluation time points. Last, but not least, there is an absolute need to adopt uniform response criteria for bone metastases through an international consensus in order to better assess treatment response in terms of accuracy and objectivity.

Osteonecrosis of the jaws: clinicopathologic and radiologic characteristics, preventive and therapeutic strategies

BACKGROUND

Bisphosphonate (BP) use has increased dramatically in recent years, becoming an integral part of the overall antineoplastic management of patients with metastatic bone disease. Even though their application has shown to be effective in reducing pain and minimizing the risk of skeletal-related events, their administration may bring also adverse events such osteonecrosis of the jaws (ONJ).

METHODS

After a thorough review of the literature, important aspects of the pathophysiology, diagnosis, prevention, and treatment of ONJ are presented.

RESULTS

ONJ is evident in up to 10% of patients receiving intravenous BP treatment. Despite the fact that its exact pathophysiology is unknown, it is characterized by bone necrosis that can occur either spontaneously or after dental surgery or tooth extraction. Panoramic radiographs are useful for the diagnosis and routine assessment of patients and computed tomography can differentiate between ONJ and metastatic disease. Additionally, magnetic resonance imaging depicts local disease extension readily, and scintigraphy is the most sensitive imaging modality for detecting early involvement. Preventive measures and routine dental evaluations are essential components of the overall patient management. In the event of ONJ, stage I or II should be managed conservatively, whereas more advanced stages (III and IV) should be treated surgically.

CONCLUSION

ONJ is a well-defined clinical entity that all medical and dental doctors should be aware of, since if it is not dealt with readily and effectively, it may deteriorate the clinical status and quality of life of affected patients.

Combination ibandronate and radiotherapy for the treatment of bone metastases: Clinical evaluation and radiologic assessment

PURPOSE

Ibandronate is a single-nitrogen, noncyclic bisphosphonate with proven efficacy for reducing metastatic bone pain. In this study, we assessed the palliative effects of combined ibandronate and radiotherapy.

METHODS AND MATERIALS

Forty-five patients with bone metastases from various solid tumors received external-beam radiotherapy, 30-40 Gy over 3-4.5, weeks combined with 10 cycles of monthly intravenous ibandronate, 6 mg.

RESULTS

After combined therapy, mean bone pain scores (graded from 0 to 10) were reduced from 6.3 at baseline to 0.8 after 3 months, with further reductions at later time points (all p < 0.001). Opioid use decreased from 84% of patients at baseline (38/45) to 24% (11/45) at 3 months, with further subsequent reductions (all p < 0.001). Mean performance status and functioning scores also significantly improved. Bone density (assessed by computed tomography scan) increased by 20% vs. baseline at 3 months, 46% at 6 months, and 73% at 10 months (all p < 0.001). Lesion improvement was also demonstrated by magnetic resonance imaging. Treatment was well tolerated with no renal toxicity.

CONCLUSIONS

In this pilot study, combined radiotherapy and ibandronate provided substantial bone pain relief and increased bone density. Computed tomography-based or magnetic resonance imaging-based evaluations offer objective methods for assessing therapeutic outcomes.