Advances in radiotherapy in bone metastases in the context of new target therapies and ablative alternatives: A critical review

Patterns of failure after stereotactic body radiotherapy to non-spine bone metastases

BACKGROUND AND PURPOSE

Stereotactic body radiotherapy (SBRT) has proven useful for non-spine bone metastases (NSBM). We analyzed local relapse rates and patterns of failure after NSBM-SBRT, contrasting our results with existing contouring guidelines.

MATERIALS AND METHODS

We conducted a retrospective analysis of NSBM-SBRT treatments performed between 2013 and 2024 in a single institution. Clinical, pathologic, and treatment-related data were collected. Failure patterns were assessed based on imaging tests and categorized as in-field, marginal/out-of-field.

RESULTS

Among 119 NSBM-SBRT treatments in 85 patients, the most common primary tumors were prostate (36.1%) and breast cancer (24.4%). The coxal bone was the predominant metastatic site (52.9%). The median follow-up was 32.8 months. OS rates at 1, 2, and 3 years were 90.1%, 83.5%, and 75.8%, respectively. Twenty seven relapses were observed in the treated bone with a median recurrent tumor volume of 9.9 cm3 and a median time to recurrence of 15.1 months. Relapse-free survival in the treated bone was 89.4%, 78.5%, and 74.2% at 1, 2, and 3 years, respectively. Median recurrent tumor volume within the CTV was 50.6% and the median distance from the relapse center to the initial tumor was 11.4 mm.

CONCLUSION

NSBM-SBRT provides effective local control with relapses often occurring near the initial tumor lesion. While adherence to existing contouring guidelines captures most scenarios, consideration of larger CTV expansions may be warranted in cases with poorer prognosis. Further studies are needed to identify risk factors for relapses outside the margins and optimize volume delineation in these scenarios.

Meta-Analysis of Stereotactic Body Radiation ThERapy in Nonspine BONE Metastases (MASTER-BONES)

PURPOSE

The efficacy and safety of stereotactic body radiation therapy (SBRT) for patients with nonspine bone metastases remains in question. A systematic review and meta-analysis were performed to evaluate SBRT treatment outcomes in nonspine bone metastases.

METHODS AND MATERIALS

Eligible studies were retrieved from MEDLINE, Embase, Scielo, the Cochrane Library, and annual meeting proceedings through July 6, 2023. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guideline recommendations. Quantitative synthesis was performed using a random-effects model. Meta-regression was performed to determine correlation between clinical and treatment factors with the local failure (LF) and fracture rate. P values ≤.05 were deemed statistically significant.

RESULTS

Seven retrospective studies, with a total of 807 patients (1048 lesions) treated with SBRT were included, with median follow-up ranging from 7.6 to 26.5 months. The most common SBRT sites were pelvis (39.2%), ribs (25.8%), femur (16.7%), and humerus/shoulder region (8.7%). At 1 year, the LF and fracture rate were 7% (95% CI, 5.5%-8.5%; I2 = 0; n = 75/1048) and 5.3% (95% CI, 3%-7.5%; I2 = 0; n = 65/1010). The 2-year cumulative LF incidence was 12.1% (95% CI, 10%-15.5%). The overall survival and progression-free survival at 1 year were 82% (95% CI, 75%-88%; I2 = 82%; n = 746/867) and 33.5% (95% CI, 26%-41%; I2 = 0%; n = 51/152), with a median of 20.2 months (95% CI, 10.9-49.1 months) and 8.3 months (95% CI, 6.3-10.3 months) for overall survival and progression-free survival, respectively. Meta-regression analysis revealed a significant relationship between planning target volume and fracture rate (P < .05). Ribs (2.5%) followed by the femur (1.9%; 95% CI, 0%-6.1%) were the most common fracture sites. The occurrence of pain flare, fatigue, and dermatitis were 7%, 5.4%, and 0.65%, respectively.

CONCLUSIONS

Stereotactic body radiation proves both safety and efficacy for non-spine bone metastases, and although serious complications (grade 3) are rare, one case of grade 5 complication was reported. Careful consideration of target volume is crucial due to its link with a higher fracture risk.

What enlightenment has the development of lung cancer bone metastasis brought in the last 22 years

BACKGROUND

Lung cancer bone metastasis (LCBM) is a disease with a poor prognosis, high risk and large patient population. Although considerable scientific output has accumulated on LCBM, problems have emerged, such as confusing research structures.

AIM

To organize the research frontiers and body of knowledge of the studies on LCBM from the last 22 years according to their basic research and translation, clinical treatment, and clinical diagnosis to provide a reference for the development of new LCBM clinical and basic research.

METHODS

We used tools, including R, VOSviewer and CiteSpace software, to measure and visualize the keywords and other metrics of 1903 articles from the Web of Science Core Collection. We also performed enrichment and protein-protein interaction analyses of gene expression datasets from LCBM cases worldwide.

RESULTS

Research on LCBM has received extensive attention from scholars worldwide over the last 20 years. Targeted therapies and immunotherapies have evolved into the mainstream basic and clinical research directions. The basic aspects of drug resistance mechanisms and parathyroid hormone-related protein may provide new ideas for mechanistic study and improvements in LCBM prognosis. The produced molecular map showed that ribosomes and focal adhesion are possible pathways that promote LCBM occurrence.

CONCLUSION

Novel therapies for LCBM face animal testing and drug resistance issues. Future focus should centre on advancing clinical therapies and researching drug resistance mechanisms and ribosome-related pathways.

Optimizing Clinical Implementation of Hypofractionation: Comprehensive Evidence Synthesis and Practical Guidelines for Low- and Middle-Income Settings

The global cancer burden, especially in low- and middle-income countries (LMICs), worsens existing disparities, amplified by the rising costs of advanced treatments. The shortage of radiation therapy (RT) services is a significant issue in LMICs. Extended conventional treatment regimens pose significant challenges, especially in resource-limited settings. Hypofractionated radiotherapy (HRT) and ultra-hypofractionated/stereotactic body radiation therapy (SBRT) offer promising alternatives by shortening treatment durations. This approach optimizes the utilization of radiotherapy machines, making them more effective in meeting the growing demand for cancer care. Adopting HRT/SBRT holds significant potential, especially in LMICs. This review provides the latest clinical evidence and guideline recommendations for the application of HRT/SBRT in the treatment of breast, prostate, and lung cancers. It emphasizes the critical importance of rigorous training, technology, stringent quality assurance, and safety protocols to ensure precise and secure treatments. Additionally, it addresses practical considerations for implementing these treatments in LMICs, highlighting the need for comprehensive support and collaboration to enhance patient access to advanced cancer care.

Changes in Spinal Instability After Conventional Radiotherapy for Painful Vertebral Bone Metastases

OBJECTIVE

Precise assessment of spinal instability is critical before and after radiotherapy (RT) for evaluating the effectiveness of RT. Therefore, we retrospectively evaluated the efficacy of RT in spinal instability over a period of 6 months after RT, utilizing the spinal instability neoplastic score (SINS) in patients with painful spinal metastasis. We retrospectively evaluated 108 patients who received RT for painful vertebral metastasis in our institution. Mechanical pain at metastatic vertebrae, radiological responses of irradiated vertebrae, and spinal instability were assessed. Follow-up assessments were done at the start of and at intervals of 1, 2, 3, 4, and 6 months after RT, with the pain disappearing in 67%, 85%, 93%, 97%, and 100% of the patients, respectively. The median SINS were 8, 6, 6, 5, 5, and 4 at the beginning and after 1, 2, 3, 4, and 6 months of RT, respectively. Multivariate analysis revealed that posterolateral involvement of spinal elements (PLISE) was the only risk factor for continuous potentially unstable/unstable spine at 1 month. In conclusion, there was improvement of pain, and recalcification results in regaining spinal stability over time after RT although vertebral body collapse and malalignment occur in some irradiated vertebrae. Clinicians should pay attention to PLISE in predicting continuous potentially unstable/unstable spine.

Quality of life issues in patients with bone metastases: A systematic review

INTRODUCTION

Bones are frequent sites of metastatic disease, observed in 30-75% of advanced cancer patients. Quality of life (QoL) is an important endpoint in studies evaluating the treatments of bone metastases (BM), and many patient-reported outcome tools are available. The primary objective of this systematic review was to compile a list of QoL issues relevant to BM and its interventions. The secondary objective was to identify common tools used to assess QoL in patients with BM, and the QoL issues they fail to address.

METHODS

A search was conducted on Ovid MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases between 1946 and 27 January 2023 with the keywords "bone metastases", "quality of life", and "patient reported outcomes". Specific QoL issues in original research studies and the QoL tools used were extracted.

RESULTS

The review identified the QoL issues most prevalent to BM in the literature. Physical and functional issues observed in patients included pain, interference with ambulation and daily activities, and fatigue. Psychological symptoms, such as helplessness, depression, and anxiety were also common. These issues interfered with patients' relationships and social activities. Items not mentioned in existing QoL tools were related to newer treatments of BM, such as pain flare, flu-like symptoms, and jaw pain due to osteonecrosis.

CONCLUSIONS

This systematic review highlights that QoL issues for patients with BM have expanded over time due to advances in BM-directed treatments. If they are relevant, additional treatment-related QoL issues identified need to be validated prospectively by patients and added to current assessment tools.

Stereotactic body radiation therapy versus conventional external beam radiotherapy for spinal metastases: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

This study aimed to compare SBRT and cEBRT for treating spinal metastases through a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

PubMed, EMBASE and Cochrane Library were searched up to 6 May 2023 for RCTs comparing SBRT and cEBRT for spinal metastases. Overall and complete pain response, local progression, overall survival, quality of life and adverse events were extracted. Data were pooled using random-effects models. Results were reported as risk ratios (RRs) for dichotomous outcomes, and hazard ratios (HRs) for time-to-event outcomes, along with their 95% confidence intervals (CIs). Heterogeneity was evaluated using the I2 statistic.

RESULTS

Three RCTs were identified involving 642 patients. No differences were seen in overall pain response comparing SBRT and cEBRT (RR at 3 months: 1.12, 95% CI, 0.74-1.70, p = 0.59; RR at 6 months: 1.29, 95% CI, 0.97-1.72, p = 0.08). Only two of three studies presented complete pain response data. SBRT demonstrated a statistically significant improvement in complete pain response compared to cEBRT (RR at 3 months: 2.52; 95% CI, 1.58-4.01; P < 0.0001; RR at 6 months: 2.48; 95% CI, 1.23-4.99; P = 0.01). There were no significant differences in local progression and overall survival. Adverse events were similar, except for any grade radiation dermatitis, which was significantly lower in SBRT arm (RR 0.17, 95% CI 0.03-0.96, P = 0.04).

CONCLUSION

SBRT is a safe treatment option for spine metastases. It may provide better complete pain response compared to cEBRT. Additional trials are needed to determine the potential benefits of SBRT in specific patient subsets.

How has the field of metastatic breast cancer in bones evolved over the past 22 years?

Background

Although knowledge on metastatic breast cancer in bones (MBCB) has increased rapidly over the past 22 years, a comprehensive and objective bibliometric analysis is still lacking.

Materials and methods

We used R, VOSviewer, and Citespace software to conduct a bibliometric analysis of 5,497 papers on MBCB from the Web of Science Core Collection (WOSCC) using author, institution, country/region, citation, and keyword indicators.

Results

A general strong sense of scholarly collaboration was noted in the MBCB field at the author, research institution, and country/region levels. We discovered some outstanding authors and highly productive institutions, but with less collaboration with other academic groups. Unbalanced and uncoordinated developments were observed among countries/regions in the field of MBCB research. We also found that by using various indicators and applying different analysis methods to them, we were able to broadly identify primary clinical practices, relevant clinical experiments, and directions for bioinformatics regarding MBCB, changes over the past 22 years, and current challenges in the field. The development of knowledge on MBCB is progressing greatly; however, MBCB is still incurable.

Conclusion

This study is the first to use bibliometrics to provide an overall analysis of the scientific output of MBCB studies. Palliative therapies for MBCB are mostly in a mature state. However, research on the molecular mechanisms and immune response to tumors related to the development of treatments to cure MBCB remains relatively immature. Therefore, further research should be undertaken in this area.

DNA Nanoclusters Combined with One-Shot Radiotherapy Augment Cancer Immunotherapy Efficiency

Immunotherapy shows immense promise for improving cancer treatment. Combining immunotherapy with radiotherapy provides a conspicuous advantage due to its enhanced abscopal effect. However, established immune tolerance mechanisms in the tumor microenvironment can hamper the generation of a sufficient abscopal effect. Herein, a type of DNA nanocluster (DNAnc) that is self-assembled by a CpG-ODNs-loaded Y-shaped double-stranded DNA vector based on the unique complementary base-pairing rules is designed. The unique structure of DNAnc makes it load more than ≈8125.5 ± 822.5 copies of CpG ODNs within one single nanostructure, which effectively increases resistance to nuclease degradation and elevates the efficiency of repolarizing macrophages to an M1-like phenotype. Mechanistic studies reveal that more DNAncs are endocytosed by macrophages in the cancer tissue and repolarized macrophages to elicit a robust abscopal effect with the accumulation of macrophages induced by radiotherapy, generating potent, long-term, and durable antitumor immunity for the inhibition of tumor metastasis and the prevention of tumor recurrence, which provides a novel strategy to boost cancer immunotherapy.

Multimodal locoregional procedures for cancer pain management: a literature review

Pain is the most common and fearsome symptom in cancer patients, particularly in the advanced stage of disease. In cancer pain management, the first option is represented by analgesic drugs, whereas surgery is rarely used. Prior to considering surgical intervention, less invasive locoregional procedures are available from the wide pain management arsenal. In this review article, comprehensive information about the most commonly used locoregional options available for treating cancer pain focusing on interventional radiology (neurolysis, augmentation techniques, and embolization) and interventional radiotherapy were provided, also highlighting the potential ways to increase the effectiveness of treatments.

Transit dosimetry of stereotactic body radiotherapy treatments with electronic portal dosimetry device in patient with spinal implant

In recent years, the use of the Electronic Portal Imaging Device (EPID) as an in vivo dosimeter has become widespread. However, reports of EPID for stereotactic body radiotherapy (SBRT) applications is scarce. There is no data on this topic especially when there are high-density materials in the radiation field. In this study, we aimed to investigate the dose distributions of SBRT treatment plans in patients with spinal implants by transit EPID dosimetry. Implants were inserted in phantoms that mimic the vertebrae, and VMAT plans were created on the phantoms to deliver 16 Gy radiation doses to the target in 1 fraction. Transit EPID measurements were performed for each irradiation. The results were compared with the treatment planning system using the gamma analysis method. According to the gamma analysis results, while the non-implant model met the acceptance criteria with a rate of 95.4%, the implanted models did not pass the test with results between the rates of 70% to 73%. In addition, while the dose difference in the isocenter was 1.3% for the non-implanted model, this difference was observed to be between 7 and 8% in the implanted models. Our study revealed that EPID can be used as transit dosimetry for the VMAT-SBRT applications. However, unacceptable dose differences were obtained by transit EPID dosimetry in the VMAT-SBRT applications of patients with an implant. In the treatment of such patients, alternative treatment methods should be preferred in which the interaction of the implants with radiation can be prevented.