Delayed postoperative radiotherapy increases the incidence of radiographic local tumor progression before radiotherapy and leads to poor prognosis in spinal metastases

Radiation Therapy for Primary and Metastatic Spine Tumors

Radiation therapy plays an important role in the management of patients with primary and metastatic spine tumors. Technological innovations in the past decade have allowed for improved targeting, dose escalation, and precision of radiation therapy while concomitant improvements in surgical techniques have resulted in improved outcomes with reduced morbidity. Patients with cancer have increasingly complex oncologic needs, and multidisciplinary management is more essential than ever. This review will provide an overview of radiation principles, modern radiation techniques, management algorithms, and expected toxicities of common radiation treatments in the management of spine tumors.

Earlier Radiation Is Associated with Improved 1-Year Survival After Metastatic Spine Tumor Surgery

OBJECTIVE

In patients undergoing metastatic spine surgery, we sought to 1) report time to postoperative radiation therapy (RT), 2) describe the predictive factors of time to postoperative RT, and 3) determine if earlier postoperative RT is associated with improved local recurrence (LR) and overall survival (OS).

METHODS

A single-center retrospective cohort study was undertaken of all patients undergoing spine surgery for extradural metastatic disease and receiving RT within 3 months postoperatively between January 2010 and January 2021. Time to postoperative RT was dichotomized at <1 month versus 1-3 months. The primary outcomes were LR, OS, and 1-year survival. Secondary outcomes were wound complication, Karnofsky Performance Status, and modified McCormick Scale (MMS) score. Regression analyses controlled for age, body mass index, tumor size, preoperative RT, preoperative/postoperative chemotherapy, and type of RT.

RESULTS

Of 76 patients undergoing spinal metastasis surgery and receiving postoperative RT within 3 months, 34 (44.7%) received RT within 1 month and 42 (55.2%) within 1-3 months. Patients with larger tumor size (β = -3.58; 95% confidence interval [CI], -6.59 to -0.57; P = 0.021) or new neurologic deficits (β = -16.21; 95% CI, -32.21 to -0.210; P = 0.047) had a shorter time to RT. No significant association was found between time to RT and LR or OS on multivariable logistic/Cox regression. However, patients who received RT between 1 and 3 months had a lower odds of 1-year survival compared with those receiving RT within 1 month (odds ratio, 0.18; 95% CI, 0.04-0.74; P = 0.022). Receiving RT within 1 month versus 1-3 months was not associated with wound complications (7.1% vs. 2.9%; P = 0.556) (odds ratio, 4.40; 95% CI, 0.40-118.0; P = 0.266) or Karnofsky Performance Status/modified McCormick Scale score.

CONCLUSIONS

Spine surgeons, oncologists, and radiation oncologists should make every effort to start RT within 1 month to improve 1-year survival after metastatic spine tumor surgery.

Surgical management of spinal metastases from primary thyroid carcinoma: Demographics, clinical characteristics, and treatment outcomes - A retrospective analysis

Objective

Metastatic spinal tumors represent a rare but concerning complication of primary thyroid carcinoma. We identified demographics, metastatic features, outcomes, and treatment strategies for these tumors in our institutional cohort.

Materials and Methods

We retrospectively reviewed patients surgically treated for spinal metastases of primary thyroid carcinoma. Demographics, tumor characteristics, and treatment modalities were collected. The functional outcomes were quantified using Nurik, Modified Rankin, and Karnofsky Scores.

Results

Twelve patients were identified who underwent 17 surgeries for resection of spinal metastases. The primary thyroid tumor pathologies included papillary (4/12), follicular (6/12), and Hurthle cell (2/12) subtypes. The average number of spinal metastases was 2.5. Of the primary tumor subtypes, follicular tumors averaged 2.8 metastases at the highest and Hurthle cell tumors averaged 2.0 spinal metastases at the lowest. Five patients (41.7%) underwent preoperative embolization for their spinal metastases. Seven patients (58.3%) received postoperative radiation. There was no significant difference in progression-free survival between patients receiving surgery with adjuvant radiation and surgery alone (P = 0.0773). Five patients (41.7%) experienced postoperative complications. Two patients (16.7%) succumbed to disease progression and two patients (16.7%) experienced tumor recurrence following resection. Postsurgical mean Nurik scores decreased 0.54 points, mean Modified Rankin scores decreased 0.48 points, and mean Karnofsky scores increased 4.8 points.

Conclusion

Surgery presents as an important treatment modality in the management of spinal metastases from thyroid cancer. Further work is needed to understand the predictive factors for survival and outcomes following treatment.

Spinal metastasis: narrative reviews of the current evidence and treatment modalities

The treatment for spinal metastasis has evolved significantly during the past decade. An advancement in systemic therapy has led to a prolonged overall survival in cancer patients, thus increasing the incidence of spinal metastasis. In addition, with the improved treatment armamentarium, the prediction of patient survival using traditional prognostic models may have limitations and these require the incorporation of some novel parameters to improve their prognostic accuracy. The development of minimally-invasive spinal procedures and minimal access surgical techniques have facilitated a quicker patient recovery and return to systemic treatment. These modern interventions help to alleviate pain and improve quality of life, even in candidates with a relatively short life expectancy. Radiotherapy may be considered in non-surgical candidates or as adjuvant therapy for improving local tumour control. Stereotactic radiosurgery has facilitated this even in radioresistant tumours and may even replace surgery in radiosensitive malignancies. This narrative review summarizes the current evidence leading to the paradigm shifts in the modern treatment of spinal metastasis.

Evaluation of a prospective radiation oncology departmental team review process using standardized simulation directives

INTRODUCTION

The primary objective of this study is to evaluate the utility and value of an institutional, multi-disciplinary radiation oncology team review process prior to radiotherapy (RT) simulation.

METHODS

Over a period of 3 months and through an iterative team-based process, a standardized simulation requisition directive (SSRD) was developed, piloted, modified, and subsequently implemented for all patients treated with external beam RT at a single tertiary care institution from January to December 2020. The SSRDs were reviewed at a daily multi-disciplinary radiation oncology team review conference; modifications consequential to the review were prospectively recorded in a quality database.

RESULTS

1,500 consecutive SSRDs were prospectively reviewed for this study. 397 modifications on 290 (19.3%) SSRDs were recorded and parsed into 5 main categories and 18 subcategories. The most common modifications resulted from changes in immobilization device (n=88, 22.2%), RT care path (n=56, 14.1%), and arm positioning (n=43, 10.8%). On univariate analysis, modifications were associated with RT intent, scan parameters, tumor site, and consultation type. An increased rate modifications was observed for patients had telemedicine consults (n=101, 22.7%) compared to in-person consultations (n=189, 17.9%) (p=0.032). Using logistic regression analysis, there was also a statistically significant relationship between postoperative RT delivery and modification rates (OR: 2.913, 95% CI: 1.014-8.372) (p=0.0126). Overall, only 14 patients (0.9%) needed re-simulation during the entire study period.

CONCLUSIONS

Prospective multi-disciplinary radiation oncology team review prior to simulation identifies actionable change in approximately 19% of procedures, and results in an extremely low rate (<1%) of re-simulation. As departmental processes transition to virtual platforms, thorough attention is needed to identify patients at higher risk of simulation modifications.

Stereotactic Radiosurgery for Postoperative Spine Malignancy: A Systematic Review and International Stereotactic Radiosurgery Society (ISRS) Practice Guidelines

PURPOSE

To 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 (ISRS).

MATERIALS AND METHODS

A 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 (VCF) probability was conducted.

RESULTS

The 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 I/II clinical trials. Outcomes for a total of 461 patients and 499 spinal segments were reported. 10 studies used an MRI fused to CT-simulation for treatment planning, 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 VCF 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.

CONCLUSIONS

Postoperative spine SBRT delivers a high 1-year LC with acceptably low toxicity. Patients that may benefit from this include those with oligometastatic disease, radioresistant histology, paraspinal masses and/or those with a history of prior irradiation to the affected spinal segment. The ISRS recommends a minimum interval of 8 to 14 days after invasive surgery prior to simulation for SBRT, with initiation of radiotherapy within 4 weeks of surgery. An MRI fused to the planning CT, and/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 2mm for the spinal cord is advised.