Stereotactic body radiation therapy for adrenal metastases: a retrospective review of a noninvasive therapeutic strategy

Risk factors of local control in adrenal metastases treated by stereotactic body radiation therapy - a systematic review and meta-analysis

Purpose

This study is aimed to explore risk factors affect the therapy outcomes of adrenal metastases (AM) for stereotactic body radiation therapy (SBRT) and guide clinical dose selection.

Methods and materials

PubMed, Embase and Web of Science were searched in September 22, 2022 in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). Subgroup analysis and meta-regression were used to search for sources of heterogeneity and identify risky outcomes factors. Publication bias test and sensitivity analysis were also conducted.

Results

Thirty-three studies with full text from 2009 to 2022 about AM with SBRT on 1483 patients were included. Pooled 1- and 2-year local control (LC) and overall survival(OS) were 81.7% (95% confidence interval [CI], 75.6%-86.5%), 62.8% (95% CI, 53.8%-71.8%), 67.4% (95%CI, 61.8%-73.1%) and 46.5% (95%CI, 40.4%-52.6%), respectively. Biological effective dose (BED, α/β=10Gy) and dose per fraction affected 1-year LC (Qm=23.89, 15.10; P<0.0001, 0.0001). In the range of 60-80Gy (BED10), the group of dose per fraction ≥ 9Gy achieved the excellent 1-year LC (< 9Gy: ≥ 9Gy =78%, 91%; χ2 = 10.16, P = 0.001). Tracking technology significantly affected 1- and 2-year OS (Qm = 5.73, 8.75; P = 0.017, 0.003) and high tracking adoption group showed excellent 1- and 2- year OS (78.7% [95%CI, 68.6%- 88.9%]; and 62.9% [95%CI, 53.1%-72.7%]).

Conclusion

Increasing the dose per fraction appropriately may help control locally AM lesious. Tracking technology might contribute to improve survival of advanced patients with AM. But these results need prospective studies to verify them.

Radiation Therapy in the Management of Adrenal Metastases

Adrenal glands represent a common site of metastases from several primary tumors, including lung cancer, breast cancer and melanoma. Surgical resection is considered the standard of care, but surgery is not always feasible given the challenges related to anatomical site and/or due to patient and/or disease characteristics. Stereotactic body radiation therapy (SBRT) represents a promising treatment for oligometastases, though the literature on its role for adrenal metastases is still heterogeneous. Herein are summarized the most relevant published studies on the efficacy and safety of SBRT for adrenal gland metastases. The preliminary data suggests that SBRT yields high local control rates and symptom relief with a mild pattern of toxicity. Advanced radiotherapy techniques including IMRT and VMAT, a BED10 > 72 Gy and the use of 4DCT for motion control should be considered for a high quality ablative treatment of adrenal gland metastases.

The efficacy and outcomes of stereotactic body radiotherapy in adrenal gland metastases

Aim

This retrospective study presents our single-institutional experience with stereotactic body radiotherapy for adrenal gland metastases.

Materials and Methods

We evaluated patients with adrenal metastases treated by stereotactic body radiotherapy (SBRT) from 2014 to 2020. We performed an analysis of 35 patients. The median age of the patients was 62.2. Dosimetric parameters and treatment outcomes were evaluated.

Results

The primary diagnosis of the majority of patients was non-small cell lung cancer (94.3%). Treatment was performed in a median of 3 fractions, and the median prescribed dose was 24 Gy (range 22,5-27). The median follow-up was 17 months. Treatment response according to Response Evaluation Criteria in Solid Tumours was categorized as complete response in 11 patients, partial response in nine patients, stable disease in 7, and progressive disease in eight patients. Twenty seven patients had oligometastatic disease and treatment response. Patients with oligometastatic disease had a significantly higher rate of complete response and partial response to treatment than patients with common disease (P = 0,011). The 6-month and 1-year local control rates were 68.4% and 43%, respectively. In general, SBRT was well tolerated and no acute toxicities were observed.

Conclusion

Our retrospective study shows that SBRT can be applied safely in adrenal metastases with good results especially in patients with oligometastatic disease.

Management of Oligometastatic Breast Cancer: An Expert Committee's Opinion

Patients with oligometastatic breast cancer (BC) are candidates of choice for metastasis-directed therapy (MDT). This paper summarizes the opinions of an expert committee about the management of oligometastatic BC. The experts could complete the questionnaire from 13 September 2021, to 10 October 2021, followed by a discussion. The experts were physicians working in the Province of Quebec (Canada) and specialized in BC care, including surgical oncologists, medical oncologists, and radiation oncologists. The experts provided their opinions about the context of the disease and therapeutic approach, local and systemic therapies, and the prognosis of oligometastatic BC. In addition to the expert panel's opinions about the management of oligometastatic disease per se, the experts stated that a prospective data registry should be implemented to collect data about oligometastatic BC to improve knowledge about oligometastatic BC and implement data-driven MDT. These data could also allow for the design of treatment algorithms. In conclusion, this paper presents the expert panel's opinions about the management of oligometastatic BC and highlights the needs to be met to improve the care of this condition.

Stereotactic radiotherapy for adrenal oligometastases

Approximately 50% of melanomas, 30–40% of lung and breast cancers and 10–20% of renal and gastrointestinal tumors metastasize to the adrenal gland.

Metastatic adrenal involvement is diagnosed by computed tomography (CT ) with contrast medium, ultrasound (which does not explore the left adrenal gland well), magnetic resonance imaging (MRI) with contrast medium and 18F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDGPET-CT ) which also evaluates lesion uptake. The simulation CT should be performed with contrast medium; an oral bolus of contrast medium is useful, given adrenal gland proximity to the duodenum. The simulation CT may be merged with PET-CT images with ¹⁸FDG in order to evaluate uptaking areas. In contouring, the radiologically visible and/or uptaking lesion provides the gross tumor volume (GTV ). Appropriate techniques are needed to overcome target motion. Single fraction stereotactic radiotherapy (SRT ) with median doses of 16–23 Gy is rarely used. More common are doses of 25–48 Gy in 3–10 fractions although 3 or 5 fractions are preferred. Local control at 1 and 2 years ranges from 44 to 100% and from 27 to 100%, respectively. The local control rate is as high as 90%, remaining stable during follow-up when BED_10Gy is equal to or greater than 100 Gy. SRT-related toxicity is mild, consisting mainly of gastrointestinal disorders, local pain and fatigue. Adrenal insufficiency is rare.

Modeling of Tumor Control Probability in Stereotactic Body Radiation Therapy for Adrenal Tumors

PURPOSE

Stereotactic body radiation therapy (SBRT) in the management of adrenal metastases is emerging as a well-tolerated, effective method of treatment for patients with limited metastatic disease. SBRT planning and treatment utilization are widely variable, and publications report heterogeneous radiation dose fractionation schemes and treatment outcomes. The objective of this analysis was to review the current literature on SBRT for adrenal metastases and to develop treatment guidelines and a model for tumor control probability of SBRT for adrenal metastases based on these publications.

METHODS AND MATERIALS

A literature search of all studies on SBRT for adrenal metastases published from 2008 to 2017 was performed, and outcomes in these studies were reviewed. Local control (LC) rates were fit to a statistically significant Poisson model using maximum likelihood estimation techniques.

RESULTS

One-year LC greater than 95% was achieved at an approximated biological equivalent dose with α/β = 10 Gy of 116.4 Gy.

CONCLUSIONS

While respecting normal tissue tolerances, tumor doses greater than or equal to a biological equivalent dose with α/β = 10 Gy of 116.4 Gy are recommended to achieve high LC. Further studies following unified reporting standards are needed for more robust prediction.

Stereotactic body radiation therapy (SBRT) of adrenal gland metastases in oligometastatic and oligoprogressive disease

BACKGROUND

Stereotactic body radiation therapy (SBRT) as a form of noninvasive treatment that is becoming increasingly used to manage cancers with adrenal gland metastases. There is a paucity of data on safety and efficacy of this modality. The aim of the study was to evaluate the safety and efficacy of adrenal gland SBRT in oligometastatic and oligoprogressive disease.

MATERIALS AND METHODS

In this retrospective study, we performed a single-institution analysis of 26 adrenal lesions from 23 patients with oligometastatic or oligoprogressive disease treated from 2013 to 2019 with the goal of achieving durable local control. Palliative cases were excluded. Radiation dosimetry data was collected. Kaplan Meier product estimator and Cox proportional hazards regression analysis were used for statistical analysis.

RESULTS

The median dose was 36 Gy in 3 fractions (range: 24-50 Gy and 3-6 fractions) with a median biologically effective dose (BED10) of 72 (range: 40-100). 1-year local control rate was 80% and median local control was not achieved due to a low number of failures. 1- and 2-year overall survival rates were 66% and 32%. Toxicity was mild with only one case of grade 2 nausea and no grade 3-5 toxicity. Higher neutrophil to lymphocyte ratio was associated with worse overall survival and a trend toward worse progression-free survival. In addition, worse performance status and lower BED10 were associated with worse survival. No such association could be shown for primary tumor location, histology, size or stage.

CONCLUSION

Adrenal SBRT for oligometastatic or oligoprogressive disease is a safe and effective form of treatment.

Single-Fraction Stereotactic Body Radiation Therapy: A Paradigm During the Coronavirus Disease 2019 (COVID-19) Pandemic and Beyond?

PURPOSE

Owing to the coronavirus disease 2019 (COVID-19) pandemic, radiation oncology departments have adopted various strategies to deliver radiation therapy safely and efficiently while minimizing the risk of severe acute respiratory syndrome coronavirus-2 transmission among patients and health care providers. One practical strategy is to deliver stereotactic body radiation therapy (SBRT) in a single fraction, which has been well established for treating bone metastases, although it has been infrequently used for other extracranial sites.

METHODS AND MATERIALS

A PubMed search of published articles in English related to single-fraction SBRT was performed. A critical review was performed of the articles that described clinical outcomes of single-fraction SBRT for treatment of primary extracranial cancers and oligometastatic extraspinal disease.

RESULTS

Single-fraction SBRT for peripheral early-stage non-small cell lung cancer is supported by randomized data and is strongly endorsed during the COVID-19 pandemic by the European Society for Radiotherapy and Oncology-American Society for Radiation Oncology practice guidelines. Prospective and retrospective studies supporting a single-fraction regimen are limited, although outcomes are promising for renal cell carcinoma, liver metastases, and adrenal metastases. Data are immature for primary prostate cancer and demonstrate excess late toxicity in primary pancreatic cancer.

CONCLUSIONS

Single-fraction SBRT should be strongly considered for peripheral early-stage non-small cell lung cancer during the COVID-19 pandemic to mitigate the potentially severe consequences of severe acute respiratory syndrome coronavirus-2 transmission. Although single-fraction SBRT is promising for the definitive treatment of other primary or oligometastatic cancers, multi-fraction SBRT should be the preferred regimen owing to the need for additional prospective evaluation to determine long-term efficacy and safety.

The Prognostic Role of Pretreatment Neutrophil to Lymphocyte Ratio (NLR) in Malignant Adrenal Lesions Treated With Stereotactic Body Radiation Therapy (SBRT)

OBJECTIVE

The objective of this study was to evaluate a single institution's experience with stereotactic body radiotherapy (SBRT) in treating malignant adrenal lesions, as well as the prognostic value of systemic inflammation biomarkers.

MATERIALS AND METHODS

From November 2007 to February 2018, 27 patients with malignant adrenal lesions received 31 SBRT treatments. Outcomes, measured from the date of SBRT, included overall survival (OS), local control (LC), and freedom from progression. Cox proportional hazard model was utilized to identify potential prognostic factors. Tumor response was assessed with PET Response Evaluation Criteria In Solid Tumors (PERCIST)/Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Acute toxicity was evaluated with the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03 criteria.

RESULTS

Median follow-up for all patients was 8 months. The complete response, partial response, stable disease, and progressive disease rates were 59%, 9%, 32%, and 0%, respectively. One-year LC, OS, and freedom from progression were 77.7%, 38.0%, and 10.0%, respectively. There was a trend toward significance upon multivariate analysis for pretreatment neutrophil to lymphocyte ratio >4.1 to predict inferior OS (adjusted hazard ratio=3.29, P=0.09, 1-year OS: 11% vs. 80%). There were 3 cases (10%) complicated by grade 2 acute toxicity, including nausea and fatigue. There was 1 grade 5 toxicity, as 1 case was complicated by a fatal gastric ulcer occurring 3 months after SBRT to the left adrenal gland (112.5 BED10).

CONCLUSIONS

These results support the limited existing literature, demonstrating that SBRT provides adequate LC for adrenal lesions with minimal toxicity. Pretreatment neutrophil to lymphocyte ratio may serve as a prognostic factor in these patients.

Highlights on the Management of Oligometastatic Disease

Purpose: The understanding of oligometastatic disease (OMD) is rapidly evolving and with this comes the ability to utilize a number of modalities that excel in the localized control of disease. It has been identified that there are no clear guidelines based on high-level evidence to standardized approaches toward the management of OMD. These highlights have been developed to provide a road map for all health-care professionals who are involved in the management of OMD to support standardized patient care. Methods: The Saudi Lung Cancer Guidelines Committee is a part of the Saudi Lung Cancer Association which, in turn, is part of the Saudi Thoracic Society. Considering that lung cancer constitutes a major proportion of OMD prevalence, the committee took the initiative to develop national highlights to support the management of OMD within Saudi Arabia. The committee members are national clinical leaders who collaborated with international expertise to establish these highlights to serve as a general clinical pathway in the management of OMD. Results: Standardization of the indications to diagnose oligometastases and patient selection criteria including ineligibility criteria for treatment are the basis of the highlights. Treatment approaches including surgical and the variety of radiotherapeutical options are discussed in relation to specific oligometastatic sites. Acceptable measurements for response to treatment and the future for the treatment of OMD conclude the development of the highlights. Conclusion: These are the first national highlights addressing this important disease in oncology. The implementation of these highlights as guidelines requires a robust multidisciplinary team and access to specific technology and expertise. These highlights are based on the most recent findings within the literature but will require repeated review and updating due to this rapidly evolving field in disease management.

Stereotactic Body Radiation Therapy of Adrenal Metastases: A Pooled Meta-Analysis and Systematic Review of 39 Studies with 1006 Patients

PURPOSE

To perform a systematic review and pooled meta-analysis of adrenal metastasis stereotactic body radiation therapy (SBRT) outcomes, treatment characteristics, and toxicity to define the efficacy and propose guidelines for intervention.

METHODS AND MATERIALS

We performed a comprehensive literature search of the Embase and PubMed databases of studies reporting outcome or toxicity data for photon-based SBRT of adrenal metastases in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We then conducted a meta-analysis to estimate pooled overall response, local control (LC), and overall survival and analyzed these outcomes in the context of dosimetric parameters and toxicity using metaregression.

RESULTS

Thirty-nine studies published between 2009 and 2019 reporting outcomes on 1006 patients were included. The median follow-up was 12 months, and the median biological equivalent dose (BED10, alpha/beta = 10) was 67 Gy. The pooled overall response was 54.6% (95% confidence interval [CI], 46.5%-62.5%). The pooled 1- and 2-year rates of LC were 82% (95% CI, 74%-88%) and 63% (95% CI, 50%-74%), respectively, and the pooled 1- and 2-year overall survival rates were 66% (95% CI, 57%-74%) and 42% (95% CI, 31%-53%), respectively. There was a strong positive association between SBRT dose and 1- and 2-year LC (P < .0001, P = .0002) and an association with 2-year OS (P = .03). Based on a metaregression of dose and LC, BED10 of 60 Gy, 80 Gy, and 100 Gy predicted 1-year LC of 70.5%, 84.8%, and 92.9% and 2-year LC of 47.8%, 70.1%, and 85.6%, respectively. The overall rate of grade 3 or higher toxicity was 1.8%.

CONCLUSIONS

SBRT of adrenal metastases provides good 1-year LC with an excellent safety profile, and dose escalation may be associated with improved LC. Prospective studies are needed to validate these findings and determine whether there are subsets of patients for whom adrenal metastasis-directed SBRT may confer a survival advantage.

Usefulness of Stereotactic Body Radiation Therapy for Treatment of Adrenal Gland Metastases

Purpose: This study aimed to describe our institutional experience in the use of stereotactic body radiation therapy (SBRT) for the management of adrenal gland metastases from multiple primary cancers. Materials and Methods: We retrospectively reviewed 31 patients who underwent SBRT as treatment for 33 adrenal gland lesions in the academic radiotherapy department of Oscar Lambret cancer center between May 2011 and September 2018. The primary study endpoints were 1- and 2-year local control rates, defined as the absence of progression at the treatment site based on the response evaluation criteria in solid tumors (RECIST). Toxicities were graded in accordance with the Common Terminology Criteria for Adverse Events version 4.03. Results: The average tumor volume was 33.5 cm³ (standard deviation: 51.7 cm³), and the prescribed dose ranged from 30 to 55 Gy given in 3-9 fractions. The median biological effective dose was 112.5 Gy (range: 45-115.5 Gy), assuming α/β = 10. Considering progression at distant sites or death as competing events, the 1- and 2-year actuarial local control rates were 96.5% (95% confidence interval: 84.9-99.7) and 92.6% (95% confidence interval: 79.2-98.7), respectively. According to RECIST, a complete response was achieved in 10 (32.3%) lesions, a partial response in 10 (32.3%) lesions, and stability in 8 (25.8%) lesions. Three patients presented with local relapse at 8.8, 14, and 49.4 months. After a median follow-up of 18 months (range: 4.4-66.4), the median overall survival was 33.5 months (95% confidence interval: 17-not reached), while the median progression-free survival was 7.4 months (95% confidence interval: 3.8-14.1). Treatment-related toxicity was grade 1 or 2 in 42.4% of patients, including nausea (27.3%), abdominal pain (18.2%), vomiting (15.2%), and asthenia (9.1%). None of the patients developed acute grade ≥3 or late toxicity. Conclusion: SBRT seems to be a safe and effective treatment for adrenal gland metastases in patients whose primary tumor and metastatic spread are controlled by systemic treatment. With a 2-year local control rate of 92.6%, SBRT may be considered as one of the first-line treatments in oligometastatic patients with adrenal metastases.

Managing Patients With Oligometastatic Non-Small-Cell Lung Cancer

Metastatic lung cancer has long been considered incurable, with the goal of treatment being palliation. However, a clinically meaningful number of these patients with limited metastases (approximately 25%) are living long term after definitive treatment to all sites of active disease. These patients with so-called oligometastatic disease likely represent a distinct clinical group who may possess a more indolent biology compared with their more widely metastatic counterparts. Hellman and Weichselbaum proposed the existence of the oligometastatic state, on the basis of the spectrum theory of cancer spread. The literature suggests that an oligometastatic state exists in patients with non-small-cell lung cancer (NSCLC). This observation in the setting of rapidly evolving systemic therapies, including immune checkpoint inhibitors and an increasing number of targeted therapies, represents a unique clinical opportunity. Metastasis-directed therapies to address sites of disease include surgery (metastasectomy) and/or radiation therapy. Available evidence suggests that treating patients with limited or oligometastases may improve outcomes in a meaningful way; however, the majority of the randomized data includes patients with intracranial metastatic disease, and there are limited robust, randomized data available in the setting of NSCLC with only extracranial sites of metastatic disease. Ongoing randomized trials, including NRG-LU002 and the UK Conventional Care Versus Radioablation (Stereotactic Body Radiotherapy) for Extracranial Oligometastases trial, are aimed at evaluating this question further. One of the current limitations of aggressive treatment of oligometastatic NSCLC is the inability to accurately identify these patients before therapy, yet molecular markers, including microRNA profiles, are being investigated as a promising way to identify these patients.

Real-Time Tumor-Tracking Radiotherapy and General Stereotactic Body Radiotherapy for Adrenal Metastasis in Patients With Oligometastasis

Background:

Precise local radiotherapy for adrenal metastasis can prolong the useful life of patients with oligometastasis. The aim of this retrospective, 2-center study was to establish the safety and effectiveness of real-time tumor-tracking radiotherapy and general stereotactic body radiotherapy in treating patients with adrenal metastatic tumors.

Materials and Methods:

Thirteen lesions in 12 patients were treated with real-time tumor-tracking radiotherapy (48 Gy in 8 fractions over 2 weeks) and 8 lesions in 8 patients were treated with general stereotactic body radiotherapy (40-50 Gy in 5-8 fractions over 2 weeks or 60-70 Gy in 10 fractions over 2 weeks). Overall survival rates, local control rates, and adverse effects were analyzed.

Results:

The actuarial overall survival rates for all patients at 1 and 2 years were 78.5% and 45.8%, respectively, with a median follow-up of 17.5 months, and the actuarial local control rates for all tumors at 1 and 2 years were 91.7% and 53.0%, respectively, with a median follow-up of 9 months. A complete local tumor response was obtained in 3 tumors treated by real-time tumor-tracking radiotherapy (lung adenocarcinomas with diameters of 35, 40, and 60 mm). There was a statistically significant difference in the local control between the groups treated by real-time tumor-tracking radiotherapy (100% at 1 year) and general stereotactic body radiotherapy (50% at 1 year; P < .001). No late adverse reactions at Grade 2 or higher were reported for either treatment group.

Conclusions:

This study showed that although both treatments are safe and effective, the real-time tumor-tracking radiotherapy is more effective than general stereotactic body radiotherapy in local control for adrenal metastasis.

Predictive Factors for Response and Survival in a Cohort of Oligometastatic Patients Treated With Stereotactic Body Radiation Therapy

PURPOSE

This study evaluated patients, treatment, or disease characteristics that could predict response to stereotactic body radiation therapy (SBRT) and survival in a database of patients with oligometastatic disease from different solid tumors.

METHODS AND MATERIALS

Patients treated with SBRT for oligometastatic disease between 2014 and 2015 were included. Patients were defined as oligometastatic if they were affected by a maximum of 5 active lesions in 3 different sites. They had to be treated with SBRT with radical intent.

RESULTS

The study included 358 patients. With a median follow-up of 31.83 months, local control at 6 and 24 months was 94.6% and 78.9%, respectively. Distant progression was recorded in 279 patients (77.9%). Progression-free survival at 6 and 24 months was 66.1% and 18.4%, respectively. At last follow-up, 195 patients (54.5%) were still alive in 59 cases with no evidence of disease. The median overall survival (OS) was 34.7 months (95% confidence interval, 29.66-43.83). OS at 6 and 24 months was 96.07% and 63.57%, respectively. On multivariable analysis, the presence of lung metastases (hazard ratio [HR], 0.50 [0.33-0.75]; P = .001) and nodal metastases (HR, 0.44 [0.24-0.78]; P = .005) was related to longer OS. Primary lung cancer (HR, 1.89 [1.14-3.13]; P = .013), increasing age (HR, 1.02 [1.01-1.04]; P = .002), and the presence of metastatic sites other than the irradiated ones (HR, 2.19 [1.39-3.43]; P = .001) were all independent predictors of shorter OS. Local response was associated with OS.

CONCLUSIONS

SBRT for patients with oligometastatic disease is effective. Local response is strongly correlated with patients'' prognosis, also underlying its relevance in a metastatic setting.

[Technical aspects and indications of extracranial stereotactic radiotherapy]

Extracranial stereotactic radiotherapy has developed considerably in recent years and is now an important part of the therapeutic alternatives to be offered to patients with cancer. It offers opportunities that have progressively led physicians to reconsider the therapeutic strategy, for example in the case of local recurrence in irradiated territory or oligometastatic disease. The literature on the subject is rich but, yet, there is no real consensus on therapeutic indications. This is largely due to the lack of prospective, randomized studies that have evaluated this technique with sufficient recoil. We propose a review of the literature on the technical aspects and indications of extracranial stereotactic radiotherapy.

Study protocol for the SARON trial: a multicentre, randomised controlled phase III trial comparing the addition of stereotactic ablative radiotherapy and radical radiotherapy with standard chemotherapy alone for oligometastatic non-small cell lung cancer

INTRODUCTION

Following growing evidence to support the safety, local control (LC) and potential improvement in overall survival (OS) in patients with oligometastatic non-small cell lung cancer (NSCLC) that have been treated with local ablative therapy such as stereotactic ablative radiotherapy (SABR) and stereotactic radiosurgery (SRS), we initiate the SARON trial to investigate the impact and feasibility of adding SABR/SRS and radical radiotherapy (RRT) following standard chemotherapy on OS.

METHODS AND ANALYSIS

SARON is a large, randomised controlled, multicentre, phase III trial for patients with oligometastatic EGFR, ALK and ROS1 mutation negative NSCLC (1-3 sites of synchronous metastatic disease, one of which must be extracranial). 340 patients will be recruited over 3 years from approximately 30 UK sites and randomised to receive either standard platinum-doublet chemotherapy only (control arm) or standard chemotherapy followed by RRT/SABR to their primary tumour and then SABR/SRS to all other metastatic sites (investigational arm). The primary endpoint is OS; the study is powered to detect an improvement in median survival from 9.9 months in the control arm to 14.3 months in the investigational arm with 85% power and two-sided 5% significance level. The secondary endpoints are LC, progression-free survival, new distant metastasis-free survival, toxicity and quality of life. An early feasibility review will take place after 50 randomised patients. Patients requiring both conventional thoracic RT to the primary and SABR to a thoracic metastasis will be included in a thoracic SABR safety substudy to assess toxicity and planning issues in this subgroup of patients more thoroughly.

ETHICS AND DISSEMINATION

All participants are given a SARON patient information sheet and required to give written informed consent. Results will be submitted for presentation at local and international conferences and expected to be published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT02417662.

SPONSOR REFERENCE

UCL/13/0594.

SBRT to adrenal metastases provides high local control with minimal toxicity

Purpose

The adrenal glands are a common site of metastases because of their rich blood supply. Previously, adrenal metastases were treated with systemic chemotherapy or, more rarely, with surgical resection or palliative radiation therapy. Stereotactic body radiation therapy (SBRT) has recently emerged as an attractive noninvasive approach to definitively treat these lesions. We present our experience in treating adrenal metastases using SBRT and review the current literature.

Methods and materials

This is a single-institution retrospective review of patients who received SBRT to adrenal metastases originating from various primary malignancies. Patients who were eligible for SBRT included those with limited metastatic disease (≤5 sites) with otherwise controlled metastatic disease and uncontrolled adrenal metastases.

Results

Ten patients met the study's inclusion criteria and received SBRT doses of 30 to 48 Gy in 3 to 5 fractions. Acute sequelae of SBRT treatment included 4 patients with grades 1 or 2 nausea, 3 patients with grade 1 fatigue, and 1 with grade 1 diarrhea. The median follow-up was 6 months with a median overall survival of 9.9 months. One patient demonstrated progressive adrenal gland disease 18.8 months after SBRT treatment. Seven patients developed new distant metastases after treatment, with a median progression-free survival of 3.4 months. Three months after SBRT to the adrenal gland, 1 patient developed a gastrointestinal bleed.

Conclusions

These results complement the limited existing body of literature by demonstrating that SBRT provides good control of treated adrenal gland metastasis; however, high-grade late toxicities may occur. More stringent dose constraint limits may prevent associated serious adverse events.

[Hypofractionated stereotactic body radiation therapy for adrenal metastases]

Adrenal glands are a common site for metastatic spread since they represent the fourth metastatic site of solid tumors. Interest in local ablative treatments of oligometastases is growing since literature suggests better progression-free survival, quality of life and potentially overall survival in selected patients. Surgery remains the first treatment of adrenal oligometastases because results are good, with a long enough follow-up. However, stereotactic radiotherapy appears to be comparable to surgery and could be proposed to elderly, unfit, inoperable patients, or even to patients whose systemic treatment should not be suspended for too long. This article aims to present a review of published studies to date on stereotactic radiotherapy of adrenal metastases and to propose a treatment protocol.

Robotic Radiosurgery for Adrenal Gland Metastases

Introduction

The purpose of this study was to investigate the safety and efficacy of CyberKnife (CK) robotic radiosurgery for treatment of adrenal metastases.

Methods

We performed a retrospective analysis of 23 patients with adrenal metastases who had been treated with CK between October 2006 and December 2015. Fifteen patients received chemotherapy prior to radiosurgery, all patients underwent computer tomography (CT) fluoroscopically guided percutaneous placement of one to three gold fiducials into the adrenal gland. Nineteen patients were selected for single-fraction radiosurgery with a median dose of 22 Gy, four patients were treated in three fractions with a median dose of 13.5 Gy.

Results

Median follow-up time was 23.6 months. Four patients (17%) experienced local relapse during the evaluation period with a mean time of 19 months to tumor progression. The actuarial local tumor control rate was 95% after one year and 81% after two years. Three of the four patients with local recurrence were retreated with CK radiosurgery. Dynamic tumor tracking enabled accurate treatment with correlation errors less than 2 mm, despite extensive respiration-induced target motion up to 22 mm. Apart from nausea directly after treatment in five patients, we observed no early or late treatment-related side effects.

Conclusions

Single fraction robotic radiosurgery for adrenal gland metastases is a safe and effective treatment option for patients who are not eligible for surgical resection.

The expanding role of stereotactic body radiation therapy in oligometastatic solid tumors: What do we know and where are we going?

The spectrum hypothesis posits that there are distinct clinical states of metastatic progression. Early data suggest that aggressive treatment of more biologically indolent metastatic disease, characterized by metastases limited in number and destination organ, may offer an opportunity to alter the disease course, potentially allowing for longer survival, delay of systemic therapy, or even cure. The development of stereotactic body radiation therapy (SBRT) has opened new avenues for the treatment of oligometastatic disease. Early data support the use of SBRT for treating oligometastases in a number of organs, with promising rates of treated metastasis control and overall survival. Ongoing investigation is required to definitively establish benefit, determine the appropriate treatment regimen, refine patient selection, and incorporate SBRT with systemic therapies.

Stereotactic ablative radiotherapy for adrenal gland metastases: Factors influencing outcomes, patterns of failure, and dosimetric thresholds for toxicity

PURPOSE

We report our single-institution experience with stereotactic ablative radiotherapy (SABR) for adrenal metastasis and identify factors influencing outcomes, patterns of failure, and dosimetric thresholds for toxicity.

METHODS AND MATERIALS

We identified patients with adrenal metastases treated with SABR from 2009 to 2015. Toxicity was evaluated with Common Terminology Criteria for Adverse Events v4.0. Local failures were categorized as in-field, marginal, or out-of-field. New or progressive disease outside the treated adrenal gland was considered distant failure. Survival and time to local and distant failure were estimated by the Kaplan-Meier method. Prognostic factors were evaluated with a Cox proportional hazards model. Fisher's exact tests were used to compare toxicity between dosimetric thresholds.

RESULTS

Forty-three patients with 49 adrenal metastases (84% from lung) were treated with SABR to a median prescribed dose of 60 Gy in 10 fractions. Median overall survival time was 19 months, and 1- and 2-year rates were 65% and 42%, respectively. Bilateral adrenal metastases were associated with worse overall survival (P = .01). Median progression-free survival (PFS) time was 6 months, with most progressions being distant failure (most often to brain or bone). PFS was better in patients with a solitary adrenal metastasis (P = .03). Median time to local failure was not reached; the 1-year freedom from local failure rate was 74%. Nine failures were in field and 1 was marginal; no local failures occurred in lesions treated with biologically equivalent doses of >100 Gy. No patient experienced grade 3-5 toxicity. Low-grade gastrointestinal toxicity was common, but grade 2 toxicity was avoided in patients with a maximum stomach-bowel point dose of ≤50 Gy (P = .03). Low-grade adrenal insufficiency was common with bilateral treatment.

CONCLUSION

SABR was well tolerated and resulted in good 1-year local control; PFS was promising for patients with solitary metastases. Low-grade toxicity was common, but can be minimized with strict dosimetric constraints.

Minimally Invasive Stereotactical Radio-ablation of Adrenal Metastases as an Alternative to Surgery

Purpose

The purpose of this study was to study the clinical outcome for patients with metastases of the adrenal gland treated with stereotactic body radiation therapy.

Materials and Methods

Forty-six patients were studied retrospectively. The dose prescription was 40 Gy in four fractions. Dosimetric analysis was performed using the dose volume histograms while clinical outcome was assessed using actuarial analysis with determination of the overall survival (OS) and local control (LC) rates.

Results

The planning objectives were met for all patients. With a median follow-up period of 7.6 months, at the last follow-up 42 patients (91.3%) were alive and four had died because of distant progression. The actuarial mean OS was 28.5±1.6 months, the median was not reached. One-year and 2-year OS were 87.6±6.1%. None of the risk factors was significant in univariate analysis. Actuarial mean LC was 14.6±1.8 months (95% confidence interval [CI], 11.0 to 18.2) and median LC was 14.5±2.0 months (95% CI, 10.5 to 18.5). One-year and 2-year LC were 65.5±11.9% and 40.7±15.8%, respectively. A mild profile of toxicity was observed in the cohort of patients. Forty patients (86.9%) showed no complication (grade 0); two patients reported asthenia, six patients (13.1%) reported either pain, nausea, or vomiting. Of these six patients, five patients (10.9%) were scored as grade 1 toxicity while one patient (2.2%) was scored as grade 2.

Conclusion

Stereotactic body radiation therapy treatment provided an adequate clinical response in the management of adrenal gland metastases.

The role of stereotactic ablative radiotherapy (SBRT) in the management of oligometastatic non small cell lung cancer

Our understanding of metastatic disease has evolved significantly in the last 20 years. Considered strictly a systemic issue, local treatment would only have significant impact in terms of palliation. However, Hellman and Weichselbaum stated that there might be an intermediate state, in which controlling limited metastatic sites could improve oncologic outcomes. This is called an oligometastatic state, a point between locally confined cancer and widespread disease [1,2]. As treatment with chemotherapy alone for non small cell lung cancer (NSCLC) yields median survivals of 8-11 months [3] and minimal chances of long term survival, new strategies are needed to offer better odds for metastatic patients. Outcomes tend to be better in patients with low volume metastatic disease. [4,5], leading us to question whether the oligometastatic group of patients will gain from a more radical treatment paradigm. In this setting, ablative treatments like surgery or SBRT may provide longer survival and better local control times. There is a rationale for the use of ablative local treatments, as most failures after chemotherapy occur at sites initially affected by disease, and these sites could be a source of further dissemination. Also, chemotherapy resistance can adversely impact resolution of metastatic disease [6]. In rare cases, the abscopal effect (an immune effect arising after radiotherapy in non irradiated metastatic sites) has been described [7,8]. In this review article, we address the impact of SBRT in oligometastatic NSCLC, the most relevant prognostic factors, indications and a site specific review. This review will focus on SBRT for extracranial disease as the role for intracranial SBRT is established.

A Retrospective Review of CyberKnife Stereotactic Body Radiotherapy for Adrenal Tumors (Primary and Metastatic): Winthrop University Hospital Experience

The adrenal gland is a common site of cancer metastasis. Surgery remains a mainstay of treatment for solitary adrenal metastasis. For patients who cannot undergo surgery, radiation is an alternative option. Stereotactic body radiotherapy (SBRT) is an ablative treatment option allowing larger doses to be delivered over a shorter period of time. In this study, we report on our experience with the use of SBRT to treat adrenal metastases using CyberKnife technology. We retrospectively reviewed the Winthrop University radiation oncology data base to identify 14 patients for whom SBRT was administered to treat malignant adrenal disease. Of the factors examined, the biological equivalent dose (BED) of radiation delivered was found to be the most important predictor of local adrenal tumor control. We conclude that CyberKnife-based SBRT is a safe, non-invasive modality that has broadened the therapeutic options for the treatment of isolated adrenal metastases.

SBRT: A viable option for treating adrenal gland metastases

The management strategy of adrenal metastases depends on different clinical situations. Adrenal metastasectomy in selected patients with isolated adrenal metastases is considered the treatment of choice, showing prolonged survival compared to chemotherapy alone. More recently, Stereotactic Body Radiation Therapy (SBRT) has emerged as an alternative local ablative treatment modality although limited data are available on the use of SBRT in treating adrenal gland metastases. Preliminary results are, however, encouraging, especially in selected patients with oligometastatic disease. We herewith review and discuss the potential role of SBRT as a local ablative treatment modality for adrenal metastases.

Emerging applications of stereotactic body radiotherapy

Stereotactic body radiotherapy (SBRT) has been used extensively in patients with lung, liver and spinal tumors, and the treatment outcomes are very favorable. For certain conditions such as medically inoperable stage I non-small-cell lung cancer, liver and lung oligometastases, primary liver cancer and spinal metastases, SBRT is regarded as one of the standard therapies. In the recent years, the use of SBRT has been extended to other disease conditions and sites such as recurrent head and neck cancer, renal cell carcinoma, prostate cancer, adrenal metastasis, pancreatic cancer, gynecological malignancies, spinal cord compression, breast cancer, and stage II-III non-small-cell lung cancer. Preliminary data in the literature show promising results but the follow-up intervals are short for most studies. This paper will provide an overview of these emerging applications.

Evaluation of stereotactic body radiation therapy in the management of adrenal metastases from non-small cell lung cancer

AIMS AND BACKGROUND

In this retrospective analysis, we evaluated the use of stereotactic body radiation therapy in the management of adrenal metastases from non-small cell lung cancer and report our single center experience.

METHODS AND STUDY DESIGN

Fifteen non-small cell lung cancer patients (9 male, 6 female) with 17 adrenal metastases referred to Gulhane Military Medical Academy Radiation Oncology Department were treated using active breathing control-guided stereotactic body radiation therapy between December 2009 and October 2013. Dose per fraction was 10 Gy to deliver a total dose of 30 Gy over 3 consecutive days for all metastatic adrenal lesions. The mean gross tumor volume was 28.4 cc (range 6.6-101.5) and mean planning target volume was 57.4 cc (range 16.5-143.8).

RESULTS

At a median follow-up of 16 months, local control was 86.7% and overall survival was 33.3%. Median disease-free survival was 10 months. Treatment response according to RECIST was categorized as complete response in 3 patients (20%), partial response in 5 patients (33.3%), stable disease in 5 patients (33.3%), and progressive disease in 2 patients (13.3%). Most common acute toxicity was grade 1 nausea (n = 7) and grade 1 fatigue (n = 12). There was no case of grade ≥3 acute or late toxicity.

CONCLUSIONS

Stereotactic body radiation therapy offers a safe and efficacious management strategy for adrenal metastases from non-small cell lung cancer by providing excellent local control with negligible treatment related toxicity.

The role of stereotactic radiotherapy in the treatment of oligometastases

"Oligometastasis" describes a limited number of metastases arising typically from solid tumors whose behavior suggests an "intermediate" malignant state since it may potentially have a more favorable prognosis. Historically, selected patients with oligometastases often underwent surgical resection since anecdotal evidence suggested it could improve progression-free or overall survival. No prospective randomized trial evidence to date supports survival benefits from surgery. Short courses of highly focused, very high dose radiotherapy (stereotactic radiosurgery; stereotactic body radiotherapy) have emerged as a surgical surrogate to manage oligometastates. For solitary brain metastases, randomized study evidence supports stereotactic radiosurgery as part of their management because of overall survival benefits. Modeled after stereotactic radiosurgery, stereotactic body radiotherapy for extracranial metastases is becoming increasingly common given its efficacy and low toxicity, is an active area of clinical research, and is the subject of this review.

Surgery or ablative radiotherapy for breast cancer oligometastases

Precisely focused radiation or surgical resection of limited metastases resulted in long-term disease control and survival in multiple studies of patients with oligometastatic breast cancer. The integration of these ablative techniques into standard systemic therapy regimens has the potential to be paradigm shifting, leaving many patients without evidence of disease. Although an attractive treatment option, the utility of these therapies have not been proven in controlled studies, and improved outcomes may be because of patient selection or favorable biology alone. Ongoing studies continue to refine radiation techniques and determine the role for ablative therapies in the management of patients with metastatic breast cancer (MBC). Additionally, patient selection for metastasis-directed therapies is based on clinical criteria, with many not benefiting from therapies that may have substantial toxicities. Recent reports are beginning to uncover the biology of oligometastatic cancer, but much work is needed. Current and developing trials that integrate both clinical and translational endpoints have the potential to transform management strategies in women with limited MBC.

Oligometastasis and oligo-recurrence: more than a mirage

The standard treatment choice for cancer metastasis has been systemic management, including cytotoxic chemotherapy, hormonal manipulation, and targeted therapy. Emerging evidence has shown an oligometastatic state, an intermediate state between limited primary cancer and polymetastatic cancer, in which local therapy for metastatic lesions results in satisfactory survival comparable to non-metastatic disease. We provide a comprehensive introduction of evidence from experimental and clinical studies in favor of the oligometastatic phenotype, we review the efficacy and safety of surgery and stereotactic body radiotherapy in the treatment of oligometastases, and finally, we discuss the way to differentiate the oligometastatic state from polymetastasis.

The role of surgery and ablative radiotherapy in oligometastatic breast cancer

The ability to deliver precise focused radiation, combined with improved surgical techniques, has led to multiple reports of long-term survivors in patients with oligometastatic breast cancer. The removal or ablation of known metastases, often present after systemic therapy regimens has the potential to be paradigm shifting rendering many patients without evidence of disease. However, the utility of these therapies has not been proven in phase III studies. Additionally, patient selection for metastasis-directed therapies is based on clinical criteria, with many patients not benefiting from these therapies. Refinements of radiation techniques are continuing, and discoveries are uncovering the biology of breast cancer in the oligometastatic state among patients. Integrated into ongoing studies, and those in development, they have the potential to alter standard management strategies in oligometastatic patients.

Radical irradiation of extracranial oligometastases

Advances in radiotherapy planning and delivery have been used to treat patients with limited metastatic disease. With these techniques, high rates of treated metastasis control and low toxicity have been reported. Some patients have long disease-free intervals after radiotherapy similar to those seen after surgical resection. Ongoing studies will determine the benefit of these irradiation techniques to treat limited metastases, identify appropriate candidates, and assist in integrating these treatments into management strategies for specific diseases.

Stereotactic body radiotherapy: a critical review for nonradiation oncologists

Stereotactic body radiotherapy (SBRT) involves the treatment of extracranial primary tumors or metastases with a few, high doses of ionizing radiation. In SBRT, tumor kill is maximized and dose to surrounding tissue is minimized, by precise and accurate delivery of multiple radiation beams to the target. This is particularly challenging, because extracranial lesions often move with respiration and are irregular in shape, requiring careful treatment planning and continual management of this motion and patient position during irradiation. This review presents the rationale, process workflow, and technology for the safe and effective administration of SBRT, as well as the indications, outcome, and limitations for this technique in the treatment of lung cancer, liver cancer, and metastatic disease.

Stereotactic body radiation therapy for curative treatment of adrenal metastases

The detection of oligometastatic adrenal metastases is increasing and there are limited data supporting the use of curative intent stereotactic body radiation therapy (SBRT) to treat patients with limited metastatic disease with adrenal involvement. Therefore, we utilized a prospectively maintained database of consecutive patients treated with SBRT for limited metastatic disease (≤5 sites) to identify patients with adrenal metastases. Patients were either treated on a three-fraction dose escalation protocol or a ten fraction off-protocol regimen. Outcomes including treated-metastasis control (TMC), distant control (DC), and overall survival (OS) were calculated by the Kaplan-Meier method. Ten patients with 13 adrenal metastases were identified for this case series. The median follow-up was 14.9 months. No patient experienced grade 3 toxicity. The most common grade 1-2 acute toxicities were fatigue (80%) and GI toxicity (40%). One patient experienced late grade 2 adrenal insufficiency. Overall, the 1-year TMC rate was 73%, DC was 30%, and OS was 90%. Three treated adrenal metastases progressed, all receiving the lowest BED10 (43.2 Gy), corresponding to 24 Gy in 3 fractions. After treatment of adrenal metastases with SBRT, the median time to salvage chemotherapy was 5.3 months (range 1.0-38.8 months) and 1-year freedom from salvage chemotherapy was 44%. These results suggest that SBRT to adrenal metastases was tolerated with low toxicity in limited metastatic patients and control rates are promising. This study supports the growing body of literature treating patients with adrenal metastases with SBRT.

Stereotactic body radiotherapy for oligometastases

The management of metastatic solid tumours has historically focused on systemic treatment given with palliative intent. However, radical surgical treatment of oligometastases is now common practice in some settings. The development of stereotactic body radiotherapy (SBRT), building on improvements in delivery achieved by intensity-modulated and image-guided radiotherapy, now allows delivery of ablative doses of radiation to extracranial sites. Many non-randomised studies have shown that SBRT for oligometastases is safe and effective, with local control rates of about 80%. Importantly, these studies also suggest that the natural history of the disease is changing, with 2-5 year progression-free survival of about 20%. Although complete cure might be possible in a few patients with oligometastases, the aim of SBRT in this setting is to achieve local control and delay progression, and thereby also postpone the need for further treatment. We review published work showing that SBRT offers durable local control and the potential for progression-free survival in non-liver, non-lung oligometastatic disease at a range of sites. However, to test whether SBRT really does improve progression-free survival, randomised trials will be essential.

Stereotactic body radiotherapy for metachronous multisite oligo-recurrence: a long-surviving case with sequential oligo-recurrence in four different organs treated using locally radical radiotherapy and a review of the literature

Stereotactic body radiotherapy (SBRT) for oligometastases represents a recent trend in radiation oncology. While abundant data are available regarding the use of SBRT for the treatment of lung or liver oligometastases from various retrospective series and prospective trials, relatively little information has been accumulated for the treatment of oligometastases at sites other than the lungs and liver, particularly for sequential oligometastases in multiple organs. Oligometastases with primary lesions controlled is called “oligo-recurrence.” We describe herein the case of a lung cancer patient who developed repeated oligo-recurrence at multiple sites that were each controlled by radical radiotherapy and achieved long-term survival and discuss the merits of locally aggressive radiotherapy for this type of disease condition with reviewing the literature. Although further investigation should be undertaken to clarify the benefits, objectives, and methods of SBRT for the treatment of oligometastases, we believe utilization of SBRT may be worthwhile for patients with remote metastases who hope for treatment to acquire better local control and possible longer survival.

Stereotactic body radiotherapy treatment of extracranial metastases

Radiotherapy is an integral treatment for patients with metastatic cancer, although it is usually reserved for palliation of pain, dyspnoea, oedema, bleeding and neurological symptoms. However, the administration of high-precision radiotherapy, termed stereotactic body radiotherapy (SBRT), has the potential to significantly affect the disease course for some patients with metastatic cancer by delivering high doses of radiation to the secondary tumours with limited high-dose delivery to adjacent healthy tissues. Indeed, such accurate delivery has been firmly established as a therapy for medically inoperable early-stage non-small-cell lung cancer. To date, the technique has demonstrated improvements in controlling metastasis and, in some cases, improved palliation compared with conventionally fractionated radiotherapy. Active areas of research in SBRT include patient selection for curative intent, optimization of SBRT planning techniques, dosing schema and integration of SBRT into systemic therapies. Given the improvements in cytotoxic and targeted therapies over the past decade, studies testing the careful integration of SBRT into standard systemic therapy regimens are needed. Further investigations are also needed to understand the basic biological mechanisms underlying SBRT because they are likely to be different to those mechanisms in conventional radiotherapy.

Review and uses of stereotactic body radiation therapy for oligometastases

In patients with proven distant metastases from solid tumors, it has been a notion that the condition is incurable, warranting palliative care only. The term "oligometastases" was coined to refer to isolated sites of metastasis, whereby the entire burden of disease can be recognized as a finite number of discrete lesions that can be potentially cured with local therapies. Stereotactic body radiation therapy (SBRT) is a novel treatment modality in radiation oncology that delivers a very high dose of radiation to the tumor target with high precision using single or a small number of fractions. SBRT is the result of technological advances in patient and tumor immobilization, image guidance, and treatment planning and delivery. A number of studies, both retrospective and prospective, showed promising results in terms of local tumor control and, in a limited subset of patients, of survival. This article reviews the radiobiologic, technical, and clinical aspects of SBRT for various anatomical sites.