Use Of Stereotactic Ablative Radiotherapy Research Articles

Stereotactic Radiation Therapy in Early Non–Small Cell Lung Cancer and Interstitial Lung Disease

Patients with interstitial lung disease (ILD) and early-stage non-small cell lung cancer (NSCLC) have been reported to be at high risk of toxic effects after stereotactic ablative radiotherapy (SABR), but for many patients, there are limited alternative treatment options. To prospectively assess the benefits and toxic effects of SABR in this patient population. This prospective cohort study was conducted at 6 academic radiation oncology institutions, 5 in Canada and 1 in Scotland, with accrual between March 7, 2019, and January 12, 2022. Patients aged 18 years or older with fibrotic ILD and a diagnosis of T1-2N0 NSCLC who were not candidates for surgical resection were enrolled. Patients were treated with SABR to a dose of 50 Gy in 5 fractions every other day. The study prespecified that SABR would be considered worthwhile if median overall survival-the primary end point-was longer than 1 year, with a grade 3 to 4 risk of toxic effects less than 35% and a grade 5 risk of toxic effects less than 15%. Secondary end points included toxic effects, progression-free survival (PFS), local control (LC), quality-of-life outcomes, and changes in pulmonary function. Intention-to-treat analysis was conducted. Thirty-nine patients enrolled and received SABR. Median age was 78 (IQR, 67-83) years and 59% (n = 23) were male. At baseline, 70% (26 of 37) of patients reported dyspnea, median forced expiratory volume in first second of expiration was 80% (IQR, 66%-90%) predicted, median forced vital capacity was 84% (IQR, 69%-94%) predicted, and median diffusion capacity of the lung for carbon monoxide was 49% (IQR, 38%-61%) predicted. Median follow-up was 19 (IQR, 14-25) months. Overall survival at 1 year was 79% (95%, CI 62%-89%; P < .001 vs the unacceptable rate), and median overall survival was 25 months (95% CI, 14 months to not reached). Median PFS was 19 months (95% CI, 13-28 months), and 2-year LC was 92% (95% CI, 69%-98%). Adverse event rates (highest grade per patient) were grade 1 to 2: n = 12 (31%), grade 3: n = 4 (10%), grade 4: n = 0, and grade 5: n = 3 (7.7%, all due to respiratory deterioration). In this trial, use of SABR in patients with fibrotic ILD met the prespecified acceptability thresholds for both toxicity and efficacy, supporting the use of SABR for curative-intent treatment after a careful discussion of risks and benefits. ClinicalTrials.gov Identifier: NCT03485378.

Incorporating Stereotactic Ablative Radiotherapy into the Multidisciplinary Management of Renal Cell Carcinoma.

Stereotactic ablative radiotherapy (SABR) has challenged the conventional wisdom surrounding the radioresistance of renal cell carcinoma (RCC). In the past decade, there has been a significant accumulation of clinical data to support the safety and efficacy of SABR in RCC. Herein, we review the use of SABR across the spectrum of RCC. We performed an online search of the Pubmed database from January 1990 through April 2023. Studies of SABR/stereotactic radiosurgery targeting primary, extracranial, and intracranial metastatic RCC were included. For SABR in non-metastatic RCC, this includes its use in small renal masses, larger renal masses, and inferior vena cava tumor thrombi. In the metastatic setting, SABR can be used at diagnosis, for oligometastatic and oligoprogressive disease, and for symptomatic reasons. Notably, SABR can be used for both the primary renal tumor and metastasis-directed therapy. Management of RCC is evolving rapidly, and the role that SABR will have in this landscape is being assessed in a number of ongoing prospective clinical trials. The objective of this narrative review is to summarize the evidence corroborating the use of SABR in RCC.

FRI146 Stereotactic Ablative Radiotherapy As A Local Valuable Therapeutic Procedure To Control Aldosterone-Secreting Adrenocortical Carcinoma

Abstract Disclosure: L.M. Mermejo: None. R.H. Zanella: None. L. Cocicov: None. C.A. Molina: None. S. Tucci Jr: None. J. Elias Jr: None. V.F. Muglia: None. G. Viani: None. P.C. Elias: None. A.C. Moreira: None. M. De Castro: None. Aldosterone-secreting adrenocortical carcinomas (ACC) are rare and usually described as large tumors. We report the case of a 44-year-old man referred to our University Hospital presenting back pain, muscular weakness and hypokalemia. A year earlier, hypertension had been diagnosed triggered by the investigation of daily headaches. Throughout this period, hypertension had been refractory to antihypertensives and patient also showed progressive weight loss of 10 kg. At the time of presentation, the patient had no signs of cortisol or androgen excess, his blood pressure was 180x120 mmHg, and there was no peripheral edema or abdominal mass detected. Due to abdominal pain and liver enzymes abnormalities, an abdominal CT was performed and revealed a heterogeneously 10 x 8 x 6 cm (volume: 256 cm³) left adrenal mass compressing the left renal vein with invasion through the inferior cava vein and extending to the liver caudate lobe. He also had a sodium of 143 mmol/L, potassium of 1.2 mmol/L and metabolic alkalosis. The serum aldosterone level of 75 ng/dL and plasma direct renin concentration &amp;lt; 2 mIU/L whereas urinary fractionated metanephrines were within normal limits, suggesting a probable aldosterone-secreting ACC. His family history was negative for hypertension or adrenal diseases. The patient was initially treated with spironolactone and potassium replacement with clinical improvement and an open adrenalectomy was proposed. However, patient professed to be Jehovah's Witnesses and refused the surgery due to the risk of blood transfusions. Therefore, the patient received mitotane but owing to hepatotoxity, the drug was withdrawn after two months of follow-up. A follow up abdominal MRI after 10 months of diagnosis revealed an increase in the mass (12 x 8 x 9 cm; volume: 460 cm³) and, now, extending to the left kidney. A CT-guided percutaneous biopsy showed an ACC with a Weiss score of three and the immunohistochemistry was positive for vimentin, inhibin and MART-1/ Melan A. After a multidisciplinary discussion, it was proposed to use stereotactic ablative radiotherapy (SABR) as an alternative option. The patient accepted SABR, being treated with 35Gy/5 fractions. During the follow-up, the patients had a progressive improvement of pain complaints, reduction of tumor burden after eighteen months on control abdomen CT (9.1 x 4.9 x 8.7 cm; volume of 202 cm³), improvement of blood pressure and hypokalemia levels, reduction of antihypertensive drugs defined daily dose and potassium replacement as well as reduction of a serum aldosterone to 13 ng/dL and increased of paired renin to 25 mU/L. This is the first published report of a pure aldosterone-producing ACC patient receiving SABR. The response was significant, indicating that the use of SABR should be considered as an alternative for local treatment of aldosterone-secreting ACC when the surgery cannot be indicated. Presentation: Friday, June 16, 2023

Assessment of Precision Irradiation in Early Non-Small Cell Lung Cancer and Interstitial Lung Disease (ASPIRE-ILD): Primary Analysis of a Phase II Trial

The use of stereotactic ablative radiotherapy (SABR) in patients with fibrotic interstitial lung disease (ILD) has been associated with an increased risk of toxicity, but patients with ILD and lung cancer may have no other options for curative-intent treatment. The goal of the ASPIRE-ILD trial was to assess the benefits and toxicities of SABR in patients with fibrotic ILD. We enrolled patients with fibrotic ILD and a diagnosis of T1-2N0 NSCLC who were not candidates for surgery. All patients were centrally reviewed prior to enrollment to confirm the presence and subtype of ILD. After stratification by the ILD-GAP score (a measure of ILD severity and prognosis), patients were treated with SABR to a dose of 50 Gy in 5 fractions EOD (BED = 100 Gy10), with a built-in de-escalation protocol in case of unacceptable toxicity. The primary endpoint was overall survival (OS), powered to distinguish 1-year OS >70% vs. an unacceptable rate of ≤50%. Secondary endpoints included toxicity (CTC-AE version 4.0), progression-free survival (PFS), local control (LC), patient-reported outcomes (FACT-L quality of life and cough severity), and changes in pulmonary function tests (PFTs). The study pre-specified that SABR would be considered worthwhile if median OS was >1 year, with a grade 3-4 toxicity risk <35% and a grade 5 toxicity risk <15%. Target accrual was 39 treated patients. Thirty-nine patients were enrolled and treated with SABR between March 2019 and January 2022, all to a dose of 50 Gy in 5 fractions, at 5 institutions in Canada and 1 in Scotland. Median age was 78 years (interquartile range: 67-83), 59% were male, and 92% had a history of smoking (median 43 pack-years). At baseline, 70% reported dyspnea, median FEV1 was 80% predicted and median DLCO was 49% predicted. ILD-GAP scores were as follows: ≤2 (i.e., best ILD status): n = 14; 3-5: n = 23; ≥6 (i.e., worst ILD status): n = 2. Median follow-up was 19 months. OS at 1-year was 78.9% (p<0.001 by binomial test vs. the unacceptable rate). Median OS was 25 months, median PFS was 19 months, and 2-year LC was 92%. AE rates (possibly, probably or definitely related) were as follows (highest grade per patient): grade 1-2: n = 12 (31%); grade 3: n = 4 (10%); grade 4; n = 0; grade 5 n = 3 (7.7%, all due to respiratory deterioration). AE rates did not differ by ILD-GAP category or ILD subtype. FACT-L scores trended downward over time (p = 0.07), and cough severity scale scores worsened over time (p = 0.02). Comparing last-available PFTs with baseline, DLCO declined (median: -4%; p = 0.046), FVC trended downward (median: -2.5%; p = 0.11), and FEV1 remained stable (median change: 0%). The use of SABR in patients with ILD met the pre-specified acceptability thresholds for both toxicity and efficacy, supporting the use of SABR for curative-intent treatment after a careful discussion of risks and benefits. Further studies exploring pharmacologic options to reduce toxicity may be beneficial in this population. ().

The Judicious Use of Stereotactic Ablative Radiotherapy in the Primary Management of Localized Renal Cell Carcinoma.

Localized renal cell carcinoma is primarily managed surgically, but this disease commonly presents in highly comorbid patients who are poor operative candidates. Less invasive techniques, such as cryoablation and radiofrequency ablation, are effective, but require percutaneous or laparoscopic access, while generally being limited to cT1a tumors without proximity to the renal pelvis or ureter. Active surveillance is another management option for small renal masses, but many patients desire treatment or are poor candidates for active surveillance. For poor surgical candidates, a growing body of evidence supports stereotactic ablative radiotherapy (SABR) as a safe and effective non-invasive treatment modality. For example, a recent multi-institution individual patient data meta-analysis of 190 patients managed with SABR estimated a 5.5% five-year cumulative incidence of local failure with one patient experiencing grade 4 toxicity, and no other grade ≥3 toxic events. Here, we discuss the recent developments in SABR for the management of localized renal cell carcinoma, highlighting key concepts of appropriate patient selection, treatment design, treatment delivery, and response assessment.

HPB P27 Stereotactic Ablative Radiotherapy in Colorectal Liver Metastases: A Systematic Review and Descriptive Summary of Practice

Abstract Background Treatment options for unresectable Colorectal Liver Metastases (CRLM) have, until recently, been mostly limited to radiofrequency or microwave ablation though there are some limitations. Stereotactic Ablative Radiotherapy (SABR) is being used increasingly to overcome these limitations with control rates and survival outcomes, reported to be comparable to ablation. However, there are several unknown factors regarding the use of SABR in CRLM, including the criteria for patient selection, optimal dose delivery and target volumes. This systematic review aims to summarise and describe the patient selection, indications, treatment regimens and survival outcomes for SABR in CRLM. Methods The literature was searched systematically to identify all articles reporting on SABR for CRLM, from inception until 1st January 2021. Primary research studies were included if they described the patient inclusion criteria, treatment regimens and outcomes from inoperable CRLM. Studies with extra-hepatic colorectal metastases were included if the metastases were deemed treatable with local therapies. Recommendations from the UK SABR consortium was used to categorise radiation dosage and fractionation. Data were collected on patient demographics, selection criteria, radiotherapy delivery and dosage and survival outcomes. Results Fifteen studies were included with a total of 522 patients and 770 liver metastases. Most studies (9/15) included patients with three or fewer metastases, however the tumour size varied from 4–15cm. Eleven studies stipulated that CRLM must be unresectable, with only one study defining unresectability according to patient or disease characteristics. Three quoted inoperability after multidisciplinary or tumour board decision, the remainder did not justify inoperability. Of these eleven, six studies stipulated that they must also be unsuitable for ablation. Patients with extra-hepatic metastases were included in ten studies, but the justification was inconsistent across all studies. Total radiation dose and fractionation varied across all studies, ranging from 16–75Gy and 3–8 fractions respectively. No studies pre-determined a target dosage for any cohort. Approximately half (149/301) of all patients received regimens in accordance with the UK SABR Consortium recommendations. Immobilisation methods were reported in eleven studies with nine different permutations including moulds, frames, abdominal compressions or breath control techniques. One year local control was reported at 48–96%, 2 years: 36–91% and 3 years: 26–85%. Overall survival at 1 year ranged from 53–100%, 2 years: 26–81% and 3 years: 21–65%. Conclusions There are significant variations in practice for delivering SABR for CRLM. There is no absolute consensus determining patient selection or treatment regimens. Although outcomes may seem promising in a selection of studies, the wide range of results and heterogeneity of studies means that truly reliable conclusions cannot be synthesised. Consensus statements to inform high-quality prospective studies are urgently needed to optimise treatment and improve patient outcomes.

Stereotactic Ablative Radiotherapy (SABR) for Oligometastatic Gynecologic Malignancies: A Single Institution Experience

<h3>Purpose/Objective(s)</h3> There is a paucity of data regarding use of SABR for gynecologic malignancies. This retrospective analysis was performed to evaluate the feasibility and efficacy of this treatment for this patient population. <h3>Materials/Methods</h3> 20 patients requiring 30 sites of treatment were treated at our institution. 10 patients had endometrial cancer (50%), 9 patients had ovarian cancer (45%) and 1 patient had cervical cancer (5%). 20 sites (67%) were treated with volumetric modulated arc therapy and 10 sites (33%) were treated with dynamic three-dimensional arc therapy. Sites treated included pelvic or abdominal lymph nodes (67%), neck or axillary nodes (13%), bone (10%), lung (7%), and mediastinal nodes (3%). Dose delivered was 30 Gy in 5 fractions (57%), 24-27 Gy in 3 fractions (33%), or 45-50 Gy in 5 fractions (10%). <h3>Results</h3> Median follow-up was 19 months. Grade 3-4 toxicity was not observed in any patients. Progression was defined as requiring a systemic treatment change or requiring another course of SABR. At the time of last follow-up, 10 patients (50%) had progressed. 6 patients (30%) required a change in systemic treatment. True in-field recurrence was not observed in any patients. Median progression free survival was 9.5 months. Median overall survival was not reached. 5 patients (25%) required no systemic therapy of any kind to maintain disease-free status. <h3>Conclusion</h3> SABR was well tolerated and associated with excellent local control. The use of SABR allowed many patients to delay change in systemic treatment, or to avoid systemic treatment altogether. The median progression free survival of 9.5 months in this cohort compares favorably to that expected with second- or third-line systemic therapy (4.1 and 1.7 months, respectively, for ovarian cancer). SABR should be strongly considered for patients with oligometastatic gynecologic malignancies.

Bone-only oligometastatic prostate cancer: can SABR improve outcomes? A single-center experience.

PurposeAblative treatment of oligometastases has shown survival benefit with certain tumors, although these effects still are to be demonstrated in prostate cancer. Materials and MethodsWe analysed the toxicity and clinical control results obtained in patients with bone-only oligometastatic prostate cancer treated with stereotactic ablative radiotherapy (SABR). Retrospective study on patients with metachronous oligoprogression and synchronous de novo bone-only oligometastatic prostate cancer treated with SABR and androgen deprivation therapy. ResultsTreatment schedules varied according to location and organs at risk, with biologically equivalent dose (BED) ≥100 Gy. Fifty-five bone lesions (31 patients) were treated and evaluated for toxicity, local control, progression-free survival (PFS), and overall survival (OS). After a 41-month follow-up, there was minimal acute or chronic toxicity and no G3 toxicity. The local control at 3 and 5 years was 100% and 87.1%, respectively. Median PFS and OS were 43 and 98 months, respectively. The best result in PFS was obtained with BED ≥230 Gy, delaying time to the next systemic therapy by 28.5 months. ConclusionThe use of SABR in bone oligometastases of prostate cancer is safe with minimal toxicity and excellent results in local control and PFS, delaying the start of the next systemic therapy.

Stereotactic Ablative Radiotherapy in the Treatment of Early-Stage Lung Cancer – A Done Deal?

Stereotactic ablative radiotherapy (SABR) is an important curative-intent treatment option for early-stage non-small cell lung cancer. It offers good cancer control without invasive surgery and has become the standard of care for medically inoperable patients. The literature on SABR for early-stage non-small cell lung cancer is substantial and continues to grow. However, there remain areas of controversy where data are limited – notably the use of SABR in medically operable patients. Other areas of some debate include the treatment of central/ultra-central and large (>5 cm) lesions, as well as treatment with co-existing interstitial lung disease. This review article provides an overview of the current literature together with a discussion of future directions.

UK 2022 Consensus on Normal Tissue Dose-Volume Constraints for Oligometastatic, Primary Lung and Hepatocellular Carcinoma Stereotactic Ablative Radiotherapy

The use of stereotactic ablative radiotherapy (SABR) in the UK has expanded over the past decade, in part as the result of several UK clinical trials and a recent NHS England Commissioning through Evaluation programme. A UK SABR Consortium consensus for normal tissue constraints for SABR was published in 2017, based on the existing literature at the time. The published literature regarding SABR has increased in volume over the past 5 years and multiple UK centres are currently working to develop new SABR services. A review and update of the previous consensus is therefore appropriate and timely. It is hoped that this document will provide a useful resource to facilitate safe and consistent SABR practice.

Implementation of Stereotactic Ablative Radiotherapy for the Treatment of Oligometastatic Cancer in Canada

&#x0D; The aim of this Environmental Scan is to identify and describe the use of stereotactic ablative radiotherapy in Canada, the systems in place to manage the treatment of patients with oligometastatic cancer, and the barriers and facilitators to the implementation of this treatment. The findings are based on a literature review, 22 survey responses from stakeholders, and email- and video call-based follow-up consultations with select stakeholders. Ten Canadian jurisdictions were represented by the survey respondents, who were primarily radiation oncologists.&#x0D; Stereotactic ablative radiotherapy for the treatment of oligometastatic cancer is currently being accessed in all Canadian provinces as a standard treatment option. Centres are primarily treating oligometastases in the lungs, bones (non-spine), lymph nodes, spine, and liver. Some cancer care centres have the capacity for stereotactic ablative radiotherapy to treat localized primary tumours but do not treat oligometastatic sites.&#x0D; There is a variation in patient selection criteria and treatment guidelines across Canadian jurisdictions, with most facilities following institutional guidance for the processes required for patient prioritization and treatment. There is a lack of standardized consensus guidelines with common criteria.&#x0D; Reported facilitators for the implementation of stereotactic ablative radiotherapy for the treatment of oligometastatic cancer include access to dedicated equipment and teams. Reported barriers to its implementation include the lack of standardized patient selection and treatment guidelines, and constraints in equipment and staff resources (including time).&#x0D;

CyberKnife Stereotactic Ablative Radiotherapy for Recurrent or Oligometastatic Gynecological Cancers

Purpose Use of stereotactic ablative radiotherapy (SABR) in the treatment of recurrent or metastatic lesions from a primary gynecologic cancer is a relatively new concept. The present study aims to assess the safety, efficacy, and possible toxicity profile of CyberKnife SABR, recurrent or metastatic disease. Materials/Methods CyberKnife VSI-based SABR was offered to 20 oligometastatic/recurrent gynecological cancer patients between 2013 and 2019. Patient, tumor, and treatment characteristics including radiotherapy details, clinical outcome in terms of local control rates, and toxicities are reported in this study. Results Twenty-five recurrent or oligometastatic lesions for 20 primary gynecologic cancer patients including cervical ( n = 8), ovarian ( n = 6), endometrial ( n = 5), and vulvar ( n = 1) cancers were analyzed. Of these, 4 (16%) were intracranial lesions and remaining 21 (84%) were extracranial, consisting of 14 (67%) extrapelvic and 7 (33%) pelvic lesions. The median SABR dose delivered was 60 Gy biologically effective dose (range 42–133 Gy) in an average of four fractions (range 1–6). The mean follow-up was 18 (range 2–70) months. Local tumor control was achieved in 82% of patients. There was no grade ≥ 3 toxicity recorded. Conclusion Our study results suggest that CyberKnife SABR is an effective treatment modality with no major morbidity in patients with recurrent or oligometastatic gynecological cancers.

Oligometastatic non-small cell lung cancer: a narrative review of stereotactic ablative radiotherapy.

Non-small cell lung cancer (NSCLC) is the most common and deadly malignancy in the United States. A significant portion of these individuals can present with or later develop metastatic NSCLC (mNSCLC). These patients typically do not survive more than two to three years after diagnosis despite the use of systemic therapies; however, there are individuals with low burden mNSCLC (oligometastatic disease) who can potentially be cured with the use of aggressive local therapies-such as stereotactic ablative radiotherapy (SAbR)-in conjunction with or without systemic therapy. Oligometastatic disease represents an intermediate state prior to the development of widespread metastases. SAbR has been shown to be an effective modality for treating patients with oligometastatic NSCLC. The combination of immunotherapy and SAbR likely represents one of the most effective while still tolerable therapies in this patient population. There are other subtypes of oligometastatic disease, including oligoprogressive disease which are amenable to SAbR. The current literature supports the use of SAbR in this population to increase the time of a patient's current systemic therapy; however, there are prospective studies evaluating the efficacy of treatment on progression free survival (PFS).

Consolidative stereotactic ablative radiotherapy (SABR) to intrapulmonary lesions is associated with prolonged progression-free survival and overall survival in oligometastatic NSCLC patients: A prospective phase 2 study

ObjectivesStereotactic Ablative Radiotherapy (SABR) has shown high rates of local control and prolonged survival in early-stage non-small cell lung cancer (NSCLC), though its role in oligometastatic disease is undefined. This study aimed to evaluate SABR as a local consolidative therapy (LCT) in oligometastatic NSCLC patients. MethodsIn this prospective, single-arm phase 2 trial, we sought to evaluate SABR in patients with stage IV NSCLC, with ≤ five lesions, including the primary tumor. Patients received initial systemic therapy according to international guidelines. Patients without progression after front-line therapy (two months of targeted therapy and ≥ four cycles of chemotherapy) were evaluated by an 18F-FDG-PET/CT to receive consolidative SABR (45−60 Gy in 3–5 fractions) to the primary and all intrapulmonary metastatic sites. The primary endpoint was progression-free survival (PFS); secondary endpoints were overall survival (OS) and toxicity. ResultsA total of 47 patients were included. Mean age was 58.9 years, 59.6 % were female, 87.2 % had adenocarcinoma histology, and the contralateral lung was the main site of metastases in 42.6 %. All patients received systemic front-line therapy, chemotherapy in 61.7 %, and a tyrosine kinase inhibitor (TKI) in 38.3 %. Disease control rate (DCR) and complete metabolic response (CMR) to SABR were 93.6 % and 70.2 %. Median PFS was 34.3 months (95 %CI; 31.1–38.8) for the total cohort; patients with a CMR had a median PFS of 53.9 monthsvs.31.9 months in those without CMR (p = 0.011). Median OS was not reached.Grade 1, 2, and 3 pneumonitis were observed in 79.5 % (31/39), 12.8 % (5/39) and 7.7 % (3/39), respectively. No grade ≥4 toxicities were observed. ConclusionThe use of SABR as LCT in oligometastatic NSCLC patients was well tolerated and showed favorable results regarding PFS and OS compared with historical data. The benefit was significantly higher in patients who reached a CMR as assessed by 18F-FDG-PET/CT.

Oligo-Terminologies of Oligometastatic Disease: Consistency of New Consensus Definitions within Current SABR Trials

Oligometastatic disease (OMD) is a rapidly growing area of oncology research. Consensus statements have recently been developed by ESTRO/ASTRO and ESTRO/EORTC in an effort to harmonize terminology describing OMD. The purpose of this study was to assess patient populations eligible for ongoing clinical trials evaluating stereotactic ablative radiotherapy (SABR) in OMD, in the context of key definitions from both statements. Definitions of key terms from both ESTRO/ASTRO and ESTRO/EORTC consensus statements for OMD were summarized. Using the ClinicalTrials.gov database, a search of ongoing OMD clinical trials evaluating the use of SABR was performed from inception to January 2020, using the keywords ‘oligometastasis’, ‘stereotactic radiotherapy’, and related terms. Results were independently reviewed by 2 investigators (GJL and AJA), with discrepancies settled by a third (AVL). Information from these trials including study design, population criteria, and primary endpoints were extracted. OMD was defined in general as a limited number of metastases that could be safely treated with local therapy. States of OMD were broadly categorized into de novo, repeat and induced, with synchronous and metachronous being subsets of de novo. The initial search strategy identified 293 trials, of which 85 met our eligibility criteria. Phase II trials were by far the most common (52%, n = 46). Most trials had a single treatment arm (51%, n = 43,), and 31 (36%) were randomized. The majority of trials (76%, n = 65) had populations that included all 3 subsets of OMD. Notably, 70 trials (82%) also included the previously termed oligoprogressive disease, which new consensus definitions consider a distinct entity from OMD. Progression-free survival was the most common primary endpoint (36%, n = 31), followed by local control (20%, n = 17), toxicity (16%, n = 14) and overall survival (8%, n = 7). Although the use of SABR for OMD is an active area of prospective clinical trial research, ongoing studies include mixed populations as defined by new consensus statements. Therefore, the applicability of results from these trials should be considered within relevant OMD scenarios.

A review of ongoing trials of stereotactic ablative radiotherapy for oligometastatic disease in the context of new consensus definitions.

The characterization and treatment of oligometastatic disease (OMD) are rapidly growing areas of research. Consensus statements have recently been developed by European Society for Radiotherapy and Oncology (ESTRO)/American Society for Radiation Oncology (ASTRO) and ESTRO/European Organization for Research and Treatment of Cancer (EORTC) in an effort to harmonize terminology describing OMD. The purpose of this study was to assess patient populations eligible for ongoing clinical trials evaluating stereotactic ablative radiotherapy (SABR) in OMD in the context of key definitions from both statements. Using the clinicaltrials.gov database, a search of ongoing OMD clinical trials evaluating the use of SABR was performed from inception to January 2020, using the keywords "oligometastasis", "stereotactic radiotherapy", and related terms. Results were independently reviewed by two investigators, with discrepancies settled by a third. Information from these trials including study design, population criteria, and primary endpoints were extracted. OMD was defined in general as a limited number of metastases that could be safely treated with metastasis-directed therapy. States of OMD were broadly categorized into de novo, repeat, and induced, with synchronous and metachronous being subsets of de novo. The initial search strategy identified 293 trials, of which 85 met our eligibility criteria. Phase II trials were by far the most common (n=46, 52%). Most trials had a single treatment arm (n=43, 51%), and 31 (36%) were randomized. The majority of trials (n=65, 76%) had populations that included all three subsets of OMD. Notably, 70 trials (82%) also included oligoprogressive disease, which is debatably a distinct entity from OMD. Progression-free survival was the most common primary endpoint (n=31, 36%), followed by local control (n=17, 20%), toxicity (n=14, 16%) and overall survival (n=7, 8%). Although the use of SABR for OMD is an active area of prospective clinical trial research, ongoing studies include mixed populations as defined by new consensus statements. Therefore, the applicability of results from these trials should be considered within relevant OMD scenarios.

Definitive single fraction stereotactic ablative radiotherapy for inoperable early-stage breast cancer: A case report.

We review a case of inoperable early stage breast cancer treated definitively with the use of stereotactic ablative radiotherapy (SABR). A 57-year-old female with a history of decompensated cirrhosis with early stage breast cancer was treated with 25 Gy in one fraction. At her 7-month follow up visit, there was a complete resolution of disease on imaging. This case represents a novel approach for the treatment of breast cancer with SABR when surgery is contraindicated.

Response evaluation after stereotactic ablative radiotherapy for localised non-small-cell lung cancer: an equipoise of available resource and accuracy.

There is growing evidence supporting the use of stereotactic ablative radiotherapy (SABR) on the treatment of localised stage non-small-cell lung cancer (NSCLC). Distinctive imaging challenges are posed post-SABR treatment. Thus, it is imperative to provide guidance on assessing treatment response, especially for new adopters. This commentary is about filling a gap in response evaluation after SABR for localised NSCLC.

IBS14.02 Best Management of Early Stage NSCLC in ILD Patients

IBS14.02 Best Management of Early Stage NSCLC in ILD Patients

Outcomes of Stereotactic Ablative Radiotherapy for Lymph Node Oligometastases

Stereotactic ablative radiotherapy (SABR) for the treatment of oligometastases is being investigated in ongoing prospective studies, with available phase II data suggesting favorable outcomes. However, there is little data regarding the use of SABR for oligometastatic lymph nodes (LNs). The objectives of the study are to report the demographics, toxicity and outcomes of all patients treated provincially with SABR to oligometastatic LNs. We conducted an analysis of all patients who underwent SABR to oligometastatic LNs in our provincial program, from 2013 to 2017. Some of the patients were treated on clinical trials, and data was prospectively collected. For the remaining majority of the patients, baseline patient, tumor, treatment and clinical outcome data were collected through retrospective review. Local control (LC), progression-free survival (PFS) and overall survival (OS) were analyzed by Kaplan-Meier method. Cox regression analysis was used to identify predictors of outcomes. Twenty-four patients underwent SABR to 35 LNs (median 1 and mean 1.5 LNs per patient). The primary sites were colorectal 8 (22.9%), kidney 6 (17.1%), esophagus 4 (11.4%), gallbladder 4 (11.4%), stomach 3 (8.6%), lung 3 (8.6%), skin 2 (5.7%), pancreas 2 (5.7%), liver 1 (2.9%), duodenum 1 (2.9%), and unknown origin 1 (2.9%). Four (11.4%) LNs were in the neck / supraclavicular regions, 14 (40.0%) in the hilum / mediastinum and 17 (48.6%) in the abdomen / pelvis. All patients had treated and controlled primary sites at the time of SABR. The median follow-up post-SABR was 31.7 months. The SABR dose fractionation ranged between 30-60 Gy in 5-10 fractions, with median BED10 of 72 Gy (range 41.3-105 Gy). All patients were treated with VMAT technique, with 4DCT and respiratory gating used for motion management in 19 (54.3%) cases. The 1- and 3-year LC were 85.4% and 62.7%. The median PFS was 7.6 months, with 1-year PFS at 25.7% and 3-year at 18.4%. The median OS was 45.0 months, with 1-year OS at 91.3% and 3-year at 55.7%. Thirteen (54.2%) patients initiated systemic therapy after SABR, at a median time for these patients of 10.0 months following completion of SABR. The median systemic therapy-free survival (STFS) for all patients after SABR was 17.8 months. There was no grade 3-5 toxicity as per CTCAE V5 criteria. On multivariate analysis, younger age (p=0.019) and female gender (p=0.046) were found to be factors predictive of improved OS. SABR to oligometastatic LNs achieves meaningful STFS, without significant toxicity. While the treatment yields moderate rates of long-term LC, the PFS was limited in this cohort. Further evaluation of patient and tumor selection is warranted.