Multimodal Nuclear Imaging Response as a Prognostic Indicator Following Spine Stereotactic Body Radiation Therapy

PurposeTo determine safety and efficacy of postoperative spine stereotactic body radiation therapy (SBRT) in the published literature, and to present practice recommendations on behalf of the International Stereotactic Radiosurgery Society. Methods and MaterialsA systematic review of the literature was performed, specific to postoperative spine SBRT, using PubMed and Embase databases. A meta-analysis for 1-year local control (LC), overall survival (OS), and vertebral compression fracture probability was conducted. ResultsThe literature search revealed 251 potentially relevant articles after duplicates were removed. Of these 56 were reviewed in-depth for eligibility and 12 met all the inclusion criteria for analysis. 7 studies were retrospective, 2 prospective observational and 3 were prospective phase 1 and 2 clinical trials. Outcomes for a total of 461 patients and 499 spinal segments were reported. Ten studies used a magnetic resonance imaging (MRI) scan fused to computed tomography (CT) simulation for treatment planning, and 2 investigations reported on all patients receiving a CT-myelogram at the time of planning. Meta-analysis for 1 year LC and OS was 88.9% and 57%, respectively. The crude reported vertebral compression fracture rate was 5.6%. One case of myelopathy was described in a patient with a previously irradiated spinal segment. One patient developed an esophageal fistula requiring surgical repair. ConclusionsPostoperative spine SBRT delivers a high 1-year LC with acceptably low toxicity. Patients who may benefit from this include those with oligometastatic disease, radioresistant histology, paraspinal masses, or those with a history of prior irradiation to the affected spinal segment. The International Stereotactic Radiosurgery Society recommends a minimum interval of 8 to 14 days after invasive surgery before simulation for SBRT, with initiation of radiation therapy within 4 weeks of surgery. An MRI fused to the planning CT, or the use of a CT-myelogram, are necessary for target and organ-at-risk delineation. A planning organ-at-risk volume (PRV) of 1.5 to 2 mm for the spinal cord is advised.

Pain Flare Is a Common Adverse Event in Steroid-Naïve Patients After Spine Stereotactic Body Radiation Therapy: A Prospective Clinical Trial

OBJECTIVE Spinal metastases that recur after conventional palliative radiotherapy have historically been difficult to manage due to concerns of spinal cord toxicity in the retreatment setting. Spine stereotactic body radiation therapy (SBRT), also known as stereotactic radiosurgery, is emerging as an effective and safe means of delivering ablative doses to these recurrent tumors. The authors performed a systematic review of the literature to determine the clinical efficacy and safety of spine SBRT specific to previously irradiated spinal metastases. METHODS A systematic literature review was conducted, which was specific to SBRT to the spine, using MEDLINE, Embase, Cochrane Evidence-Based Medicine Database, National Guideline Clearinghouse, and CMA Infobase, with further bibliographic review of appropriate articles. Research questions included: 1) Is retreatment spine SBRT efficacious with respect to local control and symptom control? 2) Is retreatment spine SBRT safe? RESULTS The initial literature search retrieved 2263 articles. Of these articles, 160 were potentially relevant, 105 were selected for in-depth review, and 9 studies met all inclusion criteria for analysis. All studies were single-institution series, including 4 retrospective, 3 retrospective series of prospective databases, 1 prospective, and 1 Phase I/II prospective study (low- or very low-quality data). The results indicated that spine SBRT is effective, with a median 1-year local control rate of 76% (range 66%-90%). Improvement in patients' pain scores post-SBRT ranged from 65% to 81%. Treatment delivery was safe, with crude rates of vertebral body fracture of 12% (range 0%-22%) and radiation-induced myelopathy of 1.2%. CONCLUSIONS This systematic literature review suggests that SBRT to previously irradiated spinal metastases is safe and effective with respect to both local control and pain relief. Although the evidence is limited to low-quality data, SBRT can be a recommended treatment option for reirradiation.

Molecular Status Predicts for Local Control in Patients with Non-Small Cell Lung Cancer Spinal Metastases Following Spine Stereotactic Body Radiotherapy

(OA26) Significance of Hormone Therapy & Bisphosphonate Use on Vertebral Compression Fracture (VCF) Incidence Following Spine Stereotactic Body Radiation Therapy (SBRT) for Breast Cancer Metastases

Arjun Sahgal works in the field of high-precision stereotactic radiation to the brain and spine. After training at the University of Toronto (ON, Canada) in radiation oncology, he completed a fellowship at the University of California, San Francisco (CA, USA) in brain and spine radiosurgery with Professor David Larson. Since then, he has been recognized as a national and international clinical expert and research leader in radiosurgery. His main focus is on developing spine stereotactic body radiotherapy (SBRT), also known as spine radiosurgery, as an effective therapy for patients with spinal tumors. Research achievements include publishing spinal cord tolerance guidelines for spine SBRT as part of an international multi-institutional effort. This work elucidated safe dose limits for the spinal cord specific to spine SBRT, and was the first of its kind. He has developed the spine SBRT program for the University of Toronto and is conducting the first Phase II clinical study on spine SBRT for metastases in Canada. He has also recently written national guidelines on behalf of the Canadian Association of Radiation Oncology (CARO) for the practice of spine, lung and liver SBRT, and continues to lead national and international multi-institutional groups dedicated to spine and brain radiosurgery research.

Risk of Vertebral Fracture and Local Recurrence after Palliative Spine Stereotactic Body Radiotherapy (SBRT)

This study aimed to report clinical outcomes of spine stereotactic body radiation therapy (SBRT) using biaxially rotational dynamic radiation therapy (BROAD-RT), which is a novel non-coplanar volumetric-modulated arc therapy (VMAT) technique that does not require couch rotation or patient repositioning. We retrospectively analyzed 13 patients who received spine SBRT using BROAD-RT in a prospective feasibility study conducted between August 2020 and April 2022. The prescribed dose was 27 Gy in 3 fractions. Patient-specific dosimetric quality assurance (QA) using ArcCHECK was conducted. The median age of patients was 73 years old. Primary cancers involved the prostate (23.0%, N=3), lung (15.4%, N=2), breast (15.4%, N=2), liver (15.4%, N=2), thyroid (15.4%, N=2), malignant meningioma (7.7%, N=1), and synovial sarcoma (7.7%, N=1). Overall, 84.6% of patients (N=11) had oligo-metastatic disease at the time of SBRT. QA showed average (±standard deviation) passing rates of 96.4 ± 2.5%. The median follow-up period was 36.2 months. Local control (LC) and overall survival (OS) rates were 84.6 and 100% at one year, and 59.8 and 68.4% at three years, respectively. The cumulative incidence of grade ≥2 vertebral compression fracture (VCF) was 7.7 and 23.1% at one and three years, respectively. Other than VCF, no grade ≥3 toxicities or radiation-induced myelopathies were observed. BROAD-RT enabled the easy application of non-coplanar VMAT in spine SBRT with marked accuracy. Treatment with 27 Gy in three fractions resulted in acceptable toxicity, although LC was relatively low. These findings highlight both the feasibility of BROAD-RT and the need for further investigation of dose and fractionation strategies.

Data on the benefit of stereotactic body radiation therapy (SBRT) in patients with breast cancer (BC) and bone metastases remain limited. The purpose of this study is to report our 10-year experience of bone SBRT, analyzing toxicity and prognostic factors for local control (LC); progression-free survival, and overall survival (OS). We analyzed all spine and non-spine bone SBRT performed in patients with BC during the 2012-2022 period at our institution. Treatments carried out with ablative intent in stereotactic conditions with dose/fraction ≥ 5Gy in 5 or fewer sessions were considered. Demographic, treatment, and toxicity data were recorded according to CTCAEv4. Risk factors were assessed through univariate and multivariate analysis by Cox regression. 60 bone SBRT treatments were performed during the study period. 75% were spine SBRT and 25% were non-spine SBRT (median BED4Gy was 80 Gy4). The median age was 52.5years (34-79). The median tumor volume was 2.9 cm3 (0.5-39.4). The median follow-up was 32.4months (1.2-101.7). 1 and 2years LC were 92.9 and 86.6%, respectively. 1 and 2years OS were 100 and 90.6%, respectively. Multivariate analysis (MVA) associated volume of the treated lesion ≥ 13 cm3 with worse LC (p = 0.046; HR 12.1, 95%CI = 1.1-140.3). In addition, deferring SBRT > 3months after lesion diagnosis to prioritize systemic treatment showed a significant benefit, improving the 2years LC up to 96.8% vs. 67.5% for SBRT performed before this period (p = 0.031; HR 0.1, 95%CI = 0.01-0.8). Hormonal receptors, the total number of metastases, and CA15-3 value were significantly associated with OS in MVA. During follow-up, three non-spine fractures (5%) were observed. According to our data, bone SBRT is a safe and effective technique for BC. Upfront systemic treatment before SBRT offers a benefit in LC. Therefore, SBRT should be considered after prior systemic treatment in this population.

Imaging-Based Local Control Outcomes Specific To Spine Stereotactic Body Radiotherapy (SBRT) For Prostate Cancer Metastases

Mature Outcomes of Stereotactic Body Radiotherapy for Spinal Metastases with 30 Gy in 4 Fractions

Vertebral Compression Fracture (VCF) After Spine Stereotactic Body Radiation Therapy (SBRT): Analysis of Predictive Factors

SBRT (stereotactic body radiation therapy) is widely used as a curative treatment in tumoral lesions and has become a fundamental tool for the treatment of spine metastasis. In this study, we present survival and toxicity outcomes of spine SBRT after a 2-year follow-up. Data from spine SBRT treatments performed at our institution between March 2012 and February 2020 was collected. Medical records, including demographic, primary tumor, and treatment characteristics were reviewed. Patient follow-up included clinical evaluation, imaging, and blood tests. Toxicity was recorded according to CTCAE v4.0. We analyzed 73 consecutive spine SBRT treatments in 60 patients. 39.7% of the cases had primary breast cancer and 23.3% had prostate cancer. Most cases (87.7%) were treated with a single SBRT fraction of 16Gy. Median follow-up was 26.1months (range 1.7-78.6), and 1- and 2-year overall survival (OS) rates were 96.9% and 84.2%, respectively. Local control (LC) rates at 1- and 2-years were 76.3% and 70.6%, respectively. Multivariate analysis identified histology as a prognostic factor for both OS and LC. Patients who underwent spine SBRT 6months after the spinal lesion diagnosis had LC at 2years of 88%, vs 61.7% for those who underwent SBRT before this period. No grade III or higher toxicity was reported. The vertebral compression fracture (VCF) rate was 4.1%. Spine SBRT at our institution showed a 2-year LC of 70.6%, without G3 toxicities. Delaying SBRT at least 6months to administer systemic treatment was related to an improvement in local control.

Planning for the Impact of SC.24 on Spine Stereotactic Body Radiotherapy (SBRT) Utilization at a Tertiary Cancer Center

Upon progression after upfront radiotherapy to spinal metastases, low-dose re-irradiation conventional external beam radiation (cEBRT) provides limited clinical benefit. Spine stereotactic body radiotherapy (SBRT) allows for dose escalation in the salvage setting with the potential for improved local control. To report mature clinical and imaging-based outcomes for salvage SBRT. A retrospective review was undertaken of consecutive patients with spinal metastases treated with re-irradiation spine SBRT having failed either cEBRT (n=60 with 1 prior course and n=17 with 2 or more prior cEBRT courses), or prior SBRT (n=6) to the same spinal segment. The primary outcome was local failure (LF), and secondary outcomes included overall survival (OS) and the rate of vertebral compression fracture (VCF). A total of 43 patients with 83 spinal segments treated with salvage SBRT were reviewed. The crude risk of LF was 18%, and actuarial LF rates at 6, 12, and 24 mo were 7%, 14%, and 19%, respectively. The presence of extensive paraspinal disease (hazard ratio [HR]=7.1, 95% CI 1.5-34) significantly predicted for LF. The median OS was 13.2 (95% CI 6.1-16.3) mo, and the presence of neurological deficits (HR=4.7, 95% CI 1.8-12.1) and brain metastases (HR=2.6, 95% CI 1.1-6.3) were significant prognostic factors. The crude risk of VCF was 4%, and radiation myelopathy was not observed. These data support the safety and efficacy of spinal re-irradiation with SBRT including patients with prior SBRT and multiple courses of prior cEBRT.