STEREOTACTIC BODY RADIATION THERAPY FOR METASTASES IN LONG BONES

Same-Day Magnetic Resonance-Guided Single-Fraction Stereotactic Body Radiation Therapy for Painful Non-Spine Bone Metastases - A Single-Center Study ("BONE SHOT")

Introduction and background

There is evidence for efficacy of high-dose single-fraction stereotactic body radiotherapy (SF-SBRT) for painful non-spine bone metastases (NSBMs). This study ("BONE SHOT") assessed feasibility of same-day magnetic resonance-guided (MRg) planning and SF-SBRT delivery, recorded toxicity and assessed efficacy for treating metastatic patients with NSBMs.

Materials and methods

Patients with painful (≥3/10 points on a 0-10 numeric rating scale (NRS) for pain) and radiologically confirmed NSBMs from solid organ malignancies were eligible for this prospectively acquired, single-center study. Patients received MRg-SF-SBRT via MR-Linac (ViewRay®) with same-day consultation, consent, planning and treatment. Drop-out rate, procedure times, acute toxicity and pain response were recorded.

Results

Between June 2019 and June 2020, 13 patients with 15 NSBMs were treated per protocol. Mean patient age was 64 (range, 30-87) years; most common primary cancer was gastrointestinal malignancies (38.5 %); most commonly treated site was pelvis (53.3 %). All workflows were completed as planned. Median on-table time for contouring, planning and delivery was 65 (range, 57-112) minutes. Treatments were well tolerated; one patient developed "pain flair"; no grade ≥ 3 toxicities were registered. At one week following SBRT, overall and complete pain response rates were 73.3 % and 20.0 %, respectively, which evolved to 66.7 % and 53.3 % at four weeks after SBRT; median pre-treatment pain score was 6 points, which was reduced by a median of 5 points (P = 0.0028) at four weeks.

Conclusion

The same-day MRg-SF-SBRT workflow for NSBMs was feasible, safe, and preliminary results indicate promising efficacy, warranting future trials investigating this intervention.

Impact of clinical target volume utilization on outcomes in patients with non-spine bone oligometastases treated with stereotactic ablative radiation therapy

PURPOSE

To compare local failure, marginal failure, and toxicity in non-spine bone metastases (NSBMs) treated with versus without a CTV for stereotactic ablative radiotherapy (SABR).

METHODS

The study included all patients in XXX treated with SABR for NSBMs on the XXX trial (November 2016 - July 2020) and on the XXX Oligometastases Registry (August 2020- October 2022). NSBMs were stratified based on CTV use for treatment planning.

RESULTS

148 patients with 183 NSBMs were included. 145 (79 %) NSBMs were treated with a CTV. Most lesions received 35 Gy in 5 fractions (80 %) or 24 Gy in 2 fractions (15 %). Local failure rates did not differ, with a 2-year local failure of 8.6 % (95 % confidence interval [CI] 3.9-13.2) with a CTV and 8.1 % (95 % CI 0-16.8) without a CTV (p = 0.53). Marginal failure did not differ (6.4 % [95 % CI 2.3-10.5] and 2.6 %, [95 % CI 0-7.7], respectively [p = 0.23]). 2-year cumulative incidence of grade ≥ 2 toxicity did not differ (15.8 %, 95 % CI 9.7-21.9 and 16.2 %, 95 % CI 4.2-28.2 respectively; p = 1.00). On multivariable regression, use of a CTV was not associated with the risk of local-marginal failure (hazard ratio [HR] 1.81, 95 % CI 0.62-5.31, p = 0.28). Extraosseous extension (HR 2.59, 95 % CI 1.2-5.7, p = 0.02) and lack of receipt of systemic therapy (HR 0.27, 95 % CI 0.1-0.5, p = 0.0002) were associated with higher risk.

CONCLUSIONS

Use of a CTV was not associated with local or marginal failure or toxicity. Extraosseous extension and lack of receipt of systemic therapy were associated with higher risk of local-marginal failure.

Stereotactic body radiotherapy for non-spine bone metastases: A meta-analysis and international stereotactic radiosurgery society (ISRS) clinical practice guidelines

BACKGROUND

While SBRT to NSBM has become common, particularly in the oligometastatic population, the approach to treating non-spine bone metastases (NSBM) with stereotactic body radiotherapy (SBRT) varies widely across institutions and clinical trial protocols. We present a comprehensive systematic review of the literatures to inform practice recommendations on behalf of the International Stereotactic Radiosurgery Society (ISRS).

METHODS

A systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies with at least 10 patients receiving SBRT for NSBM were identified and meta-analyses were completed to estimate pooled local control and overall survival rates. Published guidelines on NSBM SBRT were reviewed and consolidated.

RESULTS

There were 25 studies included for qualitative analysis and 18 studies for quantitative analysis consisting of 13 retrospective studies, 2 non-randomized prospective studies, 1 randomized phase 2/3 trial, and a subgroup analysis of a phase I trial. The pooled local control rates at 1 and 2 years were 95 % (95 % CI: 89 %-98 %) and 94 % (95 % CI: 86 %-98 %), respectively. Pooled overall survival rates at 1 year and 2 years were 84 % (95 % CI: 73 %-91 %) and 81 % (95 % CI: 45 %-95 %), respectively. Consensus was reached on recommendations to inform treatment simulation, target delineation, dose fractionation, and anatomic site-specific recommendations.

CONCLUSION

We present ISRS-endorsed consensus recommendations to inform best practice of SBRT to NSBM, which we found to be efficacious and associated with low rates of adverse events.

Stereotactic radiotherapy for patients with bone metastases: a selected group with low rate of radiation treatment during the last month of life?

BACKGROUND

Complex high-precision radiotherapy, such as stereotactic body radiotherapy (SBRT), should only be offered to patients with sufficiently long survival. In the context of bone metastases radiotherapy, low rates of treatment close to the end of life, e.g. last 30 days (RT30), may serve as a quality of care indicator. While traditional, pain-relieving short-course regimens have been studied comprehensively, real-world SBRT results are still limited.

METHODS

Retrospective analysis (2010-2023, n = 1117 episodes) of patients with bone metastases treated with traditional single-fraction (8 Gy × 1) or multi-fraction regimens (often 4 Gy × 5 or 3 Gy × 10) compared to stereotactic single-fraction (12-16 Gy × 1) or multi-fraction regimens.

RESULTS

Except for gender, almost all baseline variables were uneven distributed. Failure to complete fractionated radiotherapy was uncommon in the stereotactic (4%) and non-stereotactic group (3%), p = 1.0. With regard to RT30, relevant differences emerged (19% for 8-Gy single-fraction versus 0% for stereotactic single-fraction, p = 0.01). The corresponding figures were 11% for multi-fraction non-stereotactic and 2% for multi-fraction stereotactic, p = 0.08. Median overall survival was shortest after 8-Gy single-fraction irradiation (4.2 months) and longest after stereotactic multi-fraction treatment (13.9 months). Neither stereotactic radiotherapy nor multi-fraction treatment improved survival in multivariate Cox regression analysis. Factors significantly associated with longer survival included better performance status, lower LabBM score (5 standard blood test results), stable disease outside of irradiated area(s), metachronous distant metastases, longer time interval from metastatic disease to bone irradiation, and outpatient status.

CONCLUSION

The implementation of SBRT for selected patients has resulted in low rates of non-completion and RT30. Optimal selection criteria remain to be determined, but in current clinical practice we exclude patients with poor performance status, unfavorable blood test results (high LabBM score) and progressive disease sites not amenable to SBRT. Established, guideline-endorsed short-course regimens, especially 8-Gy single-fraction treatment, continue to represent an important palliative approach.

Clinical Outcomes Among Patients Treated With Stereotactic Body Radiation Therapy to Femur Metastases for Oligometastatic Disease Control or Reirradiation: Results From a Large Single-Institution Experience

Purpose

There are limited data regarding outcomes after stereotactic body radiation therapy (SBRT) for femur metastases, which was an exclusion criteria for the Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) trial. We aimed to characterize clinical outcomes from a large single institution experience.

Methods and Materials

Forty-eight patients with 53 lesions were consecutively treated with femur SBRT from May 2017 to June 2022. The Kaplan-Meier method and Cox proportional hazard models were used to characterize time-to-event endpoints and associations between baseline factors and clinical outcomes, respectively. Local control and locoregional control were defined as the absence of tumor progression within the radiation treatment field or within the treated femur, respectively.

Results

Most patients had Eastern Cooperative Oncology Group performance status 0 to 1 (90%), prostate (52%) or breast/lung (17%) cancer, and 1 to 3 lesions (100%), including 29 proximal and 5 distal. Fifty-seven percent of the lesions were treated with concurrent systemic therapy. Median planning target volume was 49.1 cc (range, 6.6-387 cc). Planning target volume V100 (%) was 99% (range, 90-100). Fractionation included 18 to 20 Gy/1F, 27 to 30 Gy/3F, and 28.5-40 Gy/5F. Forty-two percent had Mirels score ≥7 and most (94%) did not have extraosseous extension. Acute toxicities included grade 1 fatigue (15%), pain flare (7.5%), nausea (3.8%), and decreased blood counts (1.9%). Late toxicities included fracture (1.9%) at 1.5 years and osteonecrosis (4%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (2%) required fixation postradiation for progressive pain. With median follow-up 19.4 months, 1- and 2-year rates of local control were 94% and 89%, locoregional control was 83% and 67%, progression-free survival were 56% and 25%, and overall survival were 91% and 73%. Fifty percent of local regional recurrence events occurred within 5 cm of gross tumor volume.

Conclusions

Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Patterns of local regional recurrence warrant consideration of larger elective volume coverage. Additional prospective study is needed.

Practice and principles of stereotactic body radiation therapy for spine and non-spine bone metastases

Radiotherapy is the dominant treatment modality for painful spine and non-spine bone metastases (NSBM). Historically, this was achieved with conventional low dose external beam radiotherapy, however, stereotactic body radiotherapy (SBRT) is increasingly applied for these indications. Meta-analyses and randomized clinical trials have demonstrated improved pain response and more durable tumor control with SBRT for spine metastases. However, in the setting of NSBM, there is limited evidence supporting global adoption and large scale randomized clinical trials are in need. SBRT is technically demanding requiring careful consideration of organ at risk tolerance, and strict adherence to technical requirements including immobilization, simulation, contouring and image-guidance procedures. Additional considerations include follow up practices after SBRT, with appropriate imaging playing a critical role in response assessment. Finally, there is renewed research into promising new technologies that may further refine the use of SBRT in both spinal and NSBM in the years to come.

Stereotactic body radiation therapy for bone oligometastases

Stereotactic body radiation therapy is effective for the local management of oligometastases (at most five metastases) with a benefit in survival and local control. Most studies on the management of oligometastases focus on all oligometastatic sites in primary cancer and very few focus on a single oligometastatic site. In particular, there are few data on bone oligometastases, which represent one of the preferred sites for secondary cancer locations. This article focuses on the benefit of stereotactic radiotherapy for bone oligometastases of all cancers by histological types, and reviews the results of major studies in this field.

Ten-year retrospect of the investigation of proximal limbs metastasis in cancer: a multi-center study on survival outcome, limb function status and surgical procedures analysis

BACKGROUND

The aim of study was to evaluate survival outcome and limb function in cancer patients with proximal limbs metastasis. Associated factors on survival outcome and limb function were identified. The comparative analysis between intramedullary nailing and prosthesis surgery in cancer patients with proximal limb metastasis was performed.

METHODS

In this five-center retrospective study, patients diagnosed with limbs metastasis were collected. Descriptive statistics was used and log-rank test was performed to analyze the survival in subgroups. The Cox proportional hazards regression analysis was performed to identify the independent prognostic factors. The Musculoskeletal Tumor Society (MSTS) scoring system was used to evaluate limb function after surgery, and t test or analysis of variance (ANOVA) was utilized in subgroup analysis.

RESULTS

A total of 316 patients with limb metastasis were included with mean age at 61.0 years. The most common primary tumor was breast, followed by renal cancer and lung cancer. The median overall survival was 24.0 months and the 1-, 3- and 5-year survival rates were 86.9%, 34.7% and 6.8%, respectively. Primary tumor type, visceral metastasis and chemotherapy were proved to be the independent prognostic factors. The mean Musculoskeletal Tumor Society (MSTS) score was 20.5, significant difference was observed in subgroup of solitary/multiple bone metastasis, with/without pathological fracture, and type of surgery.

CONCLUSION

The present study concluded that primary tumor type, visceral metastasis and chemotherapy were three factors affecting the survival of patients. Compared with intramedullary nailing, the patients underwent prosthesis surgery showed better limb function, this procedure should be encouraged in patients with indication.

The Role of Post-Operative Radiotherapy for Non-Spine Bone Metastases (NSBMs)

Non-spine bone metastases (NSBMs) can cause significant morbidity and deterioration in the quality of life of cancer patients. This paper reviews the role of post-operative radiotherapy (PORT) in the management of NSBMs and provides suggestions for clinical practice based on the best available evidence. We identified six retrospective studies and several reviews that examined PORT for NSBMs. These studies suggest that PORT reduces local recurrence rates and provides effective pain relief. Based on the literature, PORT was typically delivered as 20 Gy in 5 fractions or 30 Gy in 10 fractions within 5 weeks of surgery. Complete coverage of the surgical hardware is an important consideration when designing an appropriate radiation plan and leads to improved local control. Furthermore, the integration of PORT in a multidisciplinary team with input from radiation oncologists and orthopedic surgeons is beneficial. A multimodal approach including PORT should be considered for an NSBM that requires surgery. However, phase III studies are needed to answer many remaining questions and optimize the management of NSBMs.

Stereotactic body radiotherapy versus conventional radiotherapy for painful bone metastases: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Stereotactic body radiotherapy (SBRT) is a promising approach in treating painful bone metastases. However, the superiority of SBRT over conventional external beam radiotherapy (cEBRT) remains controversial. Therefore, this systematic review and meta-analysis of randomised controlled trials was conducted to compare SBRT and cEBRT for the treatment of bone metastases.

METHODS

A search was conducted using PubMed on January 22, 2022, with the following inclusion criteria: (i) randomised controlled trials comparing SBRT with cEBRT for bone metastases and (ii) endpoint including pain response. Effect sizes across studies were pooled using random-effects models in a meta-analysis of risk ratios.

RESULTS

A total of 1246 articles were screened, with 7 articles comprising 964 patients (522 and 442 patients in the SBRT and cEBRT arms, respectively) meeting the inclusion criteria. The overall pain response (OR) rates of bone metastases at 3 months were 45% and 36% in the SBRT and cEBRT arms, respectively. The present analyses showed no significant difference between the two groups. In four studies included for the calculation of OR rates of spinal metastases at three months, the OR rates were 40% and 35% in the SBRT and cEBRT arms, respectively, with no significant difference between the two groups. The incidence of severe adverse effects and health-related quality of life outcomes were comparable between the two arms.

CONCLUSIONS

The superiority of SBRT over cEBRT for pain palliation in bone metastases was not confirmed in this meta-analysis. Although SBRT is a standard of care for bone metastases, patients receiving SBRT should be selected appropriately.