Pathogenesis of bone metastasis

Bridging the Gap in Understanding Bone Metastasis: A Multifaceted Perspective

The treatment of patients with advanced cancer poses clinical problems due to the complications that arise as the disease progresses. Bone metastases are a common problem that cancer patients may face, and currently, there are no effective drugs to treat these individuals. Prostate, breast, and lung cancers often spread to the bone, causing significant and disabling health conditions. The bone is a highly active and dynamic tissue and is considered a favorable environment for the growth of cancer. The role of osteoblasts and osteoclasts in the process of bone remodeling and the way in which their interactions change during the progression of metastasis is critical to understanding the pathophysiology of this disease. These interactions create a self-perpetuating loop that stimulates the growth of metastatic cells in the bone. The metabolic reprogramming of both cancer cells and cells in the bone microenvironment has serious implications for the development and progression of metastasis. Insight into the process of bone remodeling and the systemic elements that regulate this process, as well as the cellular changes that occur during the progression of bone metastases, is critical to the discovery of a cure for this disease. It is crucial to explore different therapeutic options that focus specifically on malignancy in the bone microenvironment in order to effectively treat this disease. This review will focus on the bone remodeling process and the effects of metabolic disorders as well as systemic factors like hormones and cytokines on the development of bone metastases. We will also examine the various therapeutic alternatives available today and the upcoming advances in novel treatments.

A Review on the Usage of Bone Single-Photon Emission Computed Tomography/Computed Tomography in Detecting Skeletal Metastases in the Post-COVID-19 Era: Is it Time to Ditch Planar and Single-Photon Emission Computed Tomography only Gamma Camera Systems?

Planar whole-body bone scanning (WBS) is widely used to evaluate skeletal lesions seen in cancer and noncancer cases. Frequently, degenerative, or other benign bony changes may give rise to indeterminate lesions that mimic bone metastases. In the post-COVID-19 era, there is an evolutionary phase that puts importance on global development and adaptability, which encompasses to include nuclear medicine practices worldwide. Single-photon emission computed tomography/computed tomography (SPECT/CT) can be used to improve the characterization of these lesions and help to resolve the diagnostic conundrum while reducing the need for patients to undergo multiple different examinations at various imaging departments. The fusion of SPECT and CT allows morphological characterization of functional abnormality detected by focal tracer uptake on planar scintigraphy, which provides a one-stop center imaging in nuclear medicine departments. The objective of this study was to review the diagnostic accuracy of SPECT/CT in diagnosing bone metastases in a variety of oncology and nononcology cases and to determine the feasibility of performing bone SPECT/CT in all suspected cancer cases, including cases of bone infection instead of planar imaging alone. The utilization of hybrid SPECT/CT in indeterminate bone lesions detected on planar WBS can significantly increase the diagnostic confidence and accuracy of image interpretation. Recognition of patterns of disease identified using hybrid imaging can improve the management of patients with potentially lower costs in the long term. Currently, hybrid SPECT/CT machines are becoming a norm in nuclear medicine departments, thus potentially making single planar application machines obsolete in the near future. We hypothesize that in the interest of providing a meaningful interpretation of isotope bone scans, the default protocol should involve the option of acquiring SPECT/CT images rather than relying on whole-body scans only. Departments choosing to upgrade existing equipment or those choosing to invest in only one gamma camera should proactively opt for hybrid SPECT/CT systems.

Expression of Receptor Activator of Nuclear – Kappa β Ligand in Patients with Metastatic Bone Disease

BACKGROUND: Bone metastasis is a complication that often occurs due to cancer in solid organs, and more often compared to primary bone tumors. Bone metastasis is associated with excessive osteolytic processes. AIM: This study was conducted to reveal the correlation between Receptor Activator of Nuclear factor kβ Ligand (RANKL) expression, lactate dehydrogenase (LDH), and neutrophil-lymphocyte ratio (NLR) level in patients with bone metastatic lesions. METHODS: This cross-sectional study was conducted in 15 subjects with bone metastatic lesions. The specimens were fresh bone tissues obtained by open biopsy. Expression of RANKL in mRNA level was detected quantitatively using reverse transcription-polymerase chain reaction. LDH and NLR were analyzed from the peripheral blood analysis. The correlation of RANKL expression with LDH and NLR was statistically analyzed. RESULTS: This study enrolled 15 subjects with bone metastasis disease based on the clinical, radiological, and histopathological results. The means of LDH, NLR, and RANKL expression were not significantly different. There was no significant association between the characteristics of metastatic lesion and RANKL expression. The correlation between LDH levels with RANKL expression was positive (p < 0.05), while the correlation between NLR and RANKL expression was negative (p < 0.05). CONCLUSION: RANKL expression was positively correlated with LDH and negatively correlated with the NLR. Both LDH and NLR can be used as predictive factors of RANKL expression in bone metastasis.

Computed tomography characteristics of multiple myeloma and other osteolytic metastatic bone lesions

BACKGROUND

Differentiation of multiple myeloma (MM) from osteolytic metastatic (OM) bone lesions may be critical in patients with lytic bone lesions but can be challenging for radiologists.

PURPOSE

To determine whether computed tomography (CT) can be used to distinguish between MM and other OM bone lesions.

MATERIAL AND METHODS

In this retrospective study, 320 lesions of 207 patients diagnosed with MM or OM, based on biopsy or clinical examination, were evaluated. Eight qualitative features were evaluated by two radiologists blinded to the diagnoses. The chi-square and Fisher exact tests, and logistic regression analysis, were used to evaluate the relationships between the CT findings and diagnoses.

RESULTS

High-density areas were more common in OM than MM lesions (85.2% and 19%, P < 0.001), as were perilesional sclerosis (38.9% vs. 13.2%, P < 0.001), heterogeneity (on non-contrast CT images, 60% vs. 19.1%, P < 0.001; on contrast enhanced CT images, 80.6% vs. 28.2%, P < 0.001), and ill-defined margins (34.6% vs. 9.1%, P < 0.001). Similarly, OM lesions showed high-density areas more than MM in evaluation of skeletal system subgroups (vertebrae, 93.8% vs. 29.8%, P < 0.0001; thoracic cage bones, 69.6% vs. 19.2%, P < 0.001; pelvic bones and sacrum, 84.8% vs. 7.7%, P < 0.001; peripheral skeletal bones, 81.5% vs. 8.3%, P < 0.001). Logistic regression analysis revealed that the presence of a high-density area in the lesion increased the probability of a metastasis 25.88-fold (R² = 0.516, P < 0.001).

CONCLUSION

MM and OM lesions can be differentiated by CT; OM lesions exhibit high- density areas.

Osteokines and Bone Markers at Rest and following Plyometric Exercise in Pre- and Postmenopausal Women

The effect of plyometric exercise on bone biomarkers has been studied in pediatric and young adult populations in order to better understand how exercise influences bone homeostasis. However, there are no such data in postmenopausal women, a group characterized by an uncoupling of the bone resorption-formation cycle. This study examined the serum concentrations of sclerostin, dickkopf-1 (DKK1), c-terminal crosslinking telopeptides of type I collagen (CTXI), and procollagen type I amino-terminal propeptide (PINP) at rest and following a single bout of plyometric exercise in 20 premenopausal (23.1 ± 2.3 years) and 20 postmenopausal women (57.9 ± 4.3 years). The exercise consisted of 128 jumps, organized into 5 circuit stations. Blood samples were obtained prior to and 5 min, 1 h, and 24 h postexercise. At rest, postmenopausal women had significantly higher sclerostin and CTXI, but lower DKK1 than premenopausal women. Sclerostin increased 5 min postexercise only in the premenopausal group. DKK1 decreased 24 h postexercise in the premenopausal women while it decreased 1 h postexercise in the postmenopausal women. In both groups, CTXI did not change across time and PINP decreased 5 min and 1 h postexercise (p < 0.05). The PINP/CTXI ratio decreased 5 min and 1 h postexercise then significantly increased 24 h postexercise only in premenopausal women. These results indicate that although plyometric exercise is effective in eliciting osteoanabolic effects in younger women; such an effect is not evident in postmenopausal women.

The Established Nuclear Medicine Modalities for Imaging of Bone Metastases

Background:

The skeleton is one of the frequent site of metastases in advanced cancer. Prostate, breast and renal cancers mostly metastasize to bone.

Discussion:

Malignant tumors lead to significant morbidity and mortality. Identification of bone lesions is a crucial step in diagnosis of disease at early stage, monitoring of disease progression and evaluation of therapy. Diagnosis of cancer metastases is based on uptake of bone-targeted radioactive tracer at different bone remodeling sites.

Conclusion:

This manuscript summarizes already established and evolving nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET, PET/CT) for imaging of bone metastases.

Re-irradiation of vertebral bodies

Improvements in clinical care and therapy mean that more patients are diagnosed and living longer with vertebral metastases. Thus, they are at risk of the development of recurrence that requires re-irradiation. Normal tissues often recover some of the damage caused by the primary radiotherapy with time and specific normal tissues can tolerate a considerable retreatment radiation dose. However, the risk of normal tissue damage and the impact on the quality of life must be considered and should be done with maximum care and accuracy especially in the vertebral area. For many years conventional external beam radiation therapy was the standard treatment modality. Fortunately, with crucial technological progress in the field of radiation oncology we are able to integrate body imaging with accurate treatment delivery methods as stereotactic body radiotherapy to improve the efficacy, shorten the overall treatment time and potentially reduce treatment-related toxicities. A short description of re-irradiation strategy covering diagnostic procedures, volume delineation, dose reconstructions, treatment planning, and guidelines are outlined. Moreover, publications on vertebral bodies re-irradiation summarizing available knowledge about toxicity, dose-volume constraints, local control, and pain response are followed. Although the knowledge is limited to a series of a single institution, it shows that re-irradiation is an effective treatment for local control and pain response. Furthermore, treatment was also shown to be safe with low risk of spinal cord damage which is one of the most worrisome toxicity.