Stereotactic Body Radiotherapy for Oligometastasis: Opportunities for Biology to Guide Clinical Management. Cancer J. 2016;22:247-256. [PMID: 27441744 DOI: 10.1097/ppo.0000000000000202]

Oligometastatic Disease (OMD): The Classification and Practical Review of Prospective Trials

Oligometastatic disease (OMD) is currently known as an intermediate state of cancer, characterized by a limited number of systemic metastatic lesions for which local ablative therapy could be curative. Indeed, data from multiple clinical trials have illustrated an increase in overall survival (OS) for cancer patients when local ablative therapy was included in the systemic adjuvant therapy. Given that no driver and somatic mutations specific to OMD are currently established, the diagnosis of OMD is mainly based on the results of X-ray studies. In 2020, 20 international experts from the European Society for Radiotherapy and Oncology (ESTRO) and the European Organization for Research and Treatment of Cancer (EORTC) developed a comprehensive system for the characterization and classification of OMD. They identified 17 OMD characteristics that needed to be assessed in all patients who underwent radical local treatment. These characteristics reflect the tumor biology and clinical features of the disease underlying the development of OMD independently of the primary tumor type and the number of metastatic lesions. In particular, the system involves the characteristics of the primary tumor (e.g., localization, histology, TNM stage, mutational status, specific tumor markers), clinical parameters (e.g., disease-free interval, treatment-free interval), therapies (e.g., local, radical or palliative treatment, the numbers of the therapeutic regimens), and type of OMD (e.g., invasive). Based on the aforementioned criteria, an algorithm was introduced into the clinic to classify OMDs collectively according to their nomenclature. A history of polymetastatic disease (PMD) prior to OMD is used as a criterion to delineate between induced OMD (previous history of PMD after successful therapy) and genuine OMD (no history of PMD). Genuine OMD is divided into two states: recurrent OMD (i.e., after a previous history of OMD) and de novo OMD (i.e., a first newly diagnosed oligometastatic disease). de novo OMD is differentiated into synchronous and metachronous forms depending on the length of time from the primary diagnosis to the first evidence of OMD. In the case of synchronous OMD, this period is less than 6 months. Lastly, metachronous and induced OMD are divided into oligorecurrence, oligoprogression, and oligopersistence, depending on whether OMD is firstly diagnosed during an absence (oligo recurrence) or presence (oligoprogression or oligopersistence) of active systemic therapy. This classification and nomenclature of OMD are evaluated prospectively in the OligoCare study. In this article, we present a practical review of the current concept of OMD and discuss the available prospective clinical trials and potential future directions.

Should Stereotactic Ablative Radiotherapy Be Used for Oligometastatic Disease?

Should SABR Be Used for Oligometastatic Disease?The efficacy of stereotactic ablative radiotherapy in the oligometastatic setting has not been shown in phase 3 randomized controlled trials for breast (or many other) cancers. We review the evidence base and propose a trial to address the question, should stereotactic ablative radiotherapy be used for oligometastatic disease?

The Management of Oligometastases in Non-small Cell Lung Cancer - is Stereotactic Ablative Radiotherapy now Standard of Care?

Oligometastatic non-small cell lung cancer encompasses a number of distinct clinical scenarios with a pattern of limited tumour burden on imaging. Delivering local ablative therapy to individual metastatic lesions may assist in disease modification and contribute to improved outcomes. We review the published randomised clinical trials that support the implementation of stereotactic ablative radiotherapy as a standard of care in certain oligometastatic non-small cell lung cancer clinical scenarios, and highlight the current knowledge gaps and areas of ongoing research.

Ways to improve breast cancer patients' management and clinical outcome: The 2020 Assisi Think Tank Meeting

We report on the third Assisi Think Tank Meeting (ATTM) on breast cancer, a brainstorming project which involved European radiation and clinical oncologists who were dedicated to breast cancer research and treatment. Held on February 2020, the ATTM aimed at identifying key clinical questions in current clinical practice and "grey" areas requiring research to improve management and outcomes. Before the meeting, three key topics were selected: 1) managing patients with frailty due to either age and/or multi-morbidity; 2) stereotactic radiation therapy and systemic therapy in the management of oligometastatic disease; 3) contralateral breast tumour prevention in BCRA-mutated patients. Clinical practice in these areas was investigated by means of an online questionnaire. In the lapse period between the survey and the meeting, the working groups reviewed data, on-going studies and the clinical challenges which were then discussed in-depth and subjected to intense brainstorming during the meeting; research protocols were also proposed. Methodology, outcome of discussions, conclusions and study proposals are summarized in the present paper. In conclusion, this report presents an in-depth analysis of the state of the art, grey areas and controversies in breast cancer radiation therapy and discusses how to confront them in the absence of evidence-based data to guide clinical decision-making.

Stereotactic radiotherapy for liver oligometastases

The liver is the first metastatic site in 15–25% of colorectal cancer patients and one of the first metastatic sites for lung and breast cancer patients.

A computed tomography (CT ) scan with contrast medium is a standard procedure for assessing liver lesions but magnetic resonance imaging (MRI) characterizes small lesions better thanks to its high soft-tissue contrast. Positron emission tomography with computed tomography (PET-CT ) plays a complementary role in the diagnosis of liver metastases. Triphasic (arterial, venous and time-delayed) acquisition of contrast-medium CT images is the first step in treatment planning. Since the liver exhibits a relatively wide mobility due to respiratory movements and bowel filling, appropriate techniques are needed for target identification and motion management. Contouring requires precise recognition of target lesion edges. Information from contrast MRI and/or PET-CT is crucial as they best visualize metastatic disease in the parenchyma. Even though different fractionation schedules were reported, doses and fractionation schedules for liver stereotactic radiotherapy (SRT ) have not yet been established. The best local control rates were obtained with BED₁₀ values over 100 Gy. Local control rates from most retrospective studies, which were limited by short follow-ups and included different primary tumors with intrinsic heterogeneity, ranged from 60% to 90% at 1 and 2 years. The most common SRT-related toxicities are increases in liver enzymes, hyperbilirubinemia and hypoalbuminemia. Overall, late toxicity is mild even in long-term follow-ups.

Temporality and Patterns of Metastatic Recurrence in Node-Positive Breast Cancer Following Trimodality Therapy: Opportunity for Improved Oligometastases Detection and Salvage Local Therapy

OBJECTIVES

There is evidence that detection and treatment of oligometastases (≤5 lesions) may improve survival in breast cancer patients. However, there are no current national guidelines for screening of early, asymptomatic metastases. This study examined the patterns and timing of recurrence with respect to survival in node-positive breast cancer (NPBC) patients at higher risk for developing metastases.

METHODS

A single-institution retrospective review of NPBC patients treated with trimodality therapy was performed to collect patient and disease characteristics, recurrence location, method of detection, and survival outcome. Univariate and multivariate analyses were done to identify factors associated with recurrence.

RESULTS

Ninety-four NPBC patients treated at a safety-net hospital between 2008 and 2019 were identified. Twenty-one developed recurrence and were divided into oligometastatic (OM) (n=10) or diffusely metastatic (DM) (n=11) subgroups. Median recurrence-free survival in OM and DM was 18 and 36 months, respectively. Median overall survival (OS) for OM was not reached. Median OS for DM was 57 months. Four patients with OM progressed to diffuse disease in a median period of 17 months; median survival thereafter was 57 months. All patients with recurrence had distant metastases on initial detection, with the most common site being bone (14). Recurrence was most frequently detected by computed tomography (CT) (13), with the majority of disease located within the thorax region.

CONCLUSIONS

All NPBC patients had distant metastasis at time of recurrence. Patients with OM had shorter interval to recurrence yet longer OS compared with DM. This study highlights improved surveillance imaging for timely detection of OM breast cancer that may yet be amenable to aggressive local salvage therapy to prevent progression to diffuse disease.

Metastasis-directed Therapy in Prostate Cancer: Prognostic Significance of the ESTRO/EORTC Classification in Oligometastatic Bone Disease

AIMS

Oligometastatic disease (OMD) represents a spectrum of clinical scenarios and various classification systems have been proposed. Bone-only OMD can occur in patients with advanced prostate cancer and validated decision-making tools are needed to assist patient selection for metastasis-directed therapy. The aim of the present study was to determine the prognostic utility of a classification system for OMD.

MATERIALS AND METHODS

A retrospective review was conducted of all patients with bone-only oligometastatic prostate cancer treated with stereotactic body radiotherapy (SBRT) since November 2011. SBRT was delivered using CyberKnife® and gantry-based linear accelerator platforms. All patients were classified into oligometastatic states based on the European Society for Radiotherapy and Oncology/European Organisation for Research and Treatment of Cancer (ESTRO/EORTC) classification system. Kaplan-Meier and Cox regression analyses were carried out to determine the prognostic utility of this classification system.

RESULTS

In total, 105 patients with 145 osseous metastases were treated over 119 sessions. The median follow-up after SBRT was 23 months (interquartile range 10-39.8). Twelve patients had died after a median time of 31 months. The 3-year metastatic progression-free survival was 23% (95% confidence interval 13-32) and the 3-year overall survival was 88% (95% confidence interval 80-96). Patients in a metachronous oligometastatic state were 4.50 (95% confidence interval 1.19-17.10, P = 0.03) times more likely to experience metastatic progression compared with those with synchronous oligometastases, and 6.69 (95% confidence interval 1.05-42.50, P = 0.04) times more likely to experience any failure. Hazard ratio magnitudes increased for patients in a repeat oligometastatic state. The multivariate model for both metastatic progression-free survival and failure-free survival found prostate-specific antigen doubling time <4 months (P = 0.002; P = 0.05) to independently predict for progression.

CONCLUSION

The ESTRO/EORTC classification of OMD predicts for progression in patients treated with SBRT for bone-only oligometastatic prostate cancer at our institution. Further validation in prospective series over multiple tumour sites is needed. These characterisation factors should be assessed in patients considered for metastasis-directed therapy together with established prognostic features.

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.

Current Evidence for Stereotactic Body Radiotherapy in Lung Metastases

Lung metastases are the second most common malignant neoplasms of the lung. It is estimated that 20–54% of cancer patients have lung metastases at some point during their disease course, and at least 50% of cancer-related deaths occur at this stage. Lung metastases are widely accepted to be oligometastatic when five lesions or less occur separately in up to three organs. Stereotactic body radiation therapy (SBRT) is a noninvasive, safe, and effective treatment for metastatic lung disease in carefully selected patients. There is no current consensus on the ideal dose and fractionation for SBRT in lung metastases, and it is the subject of study in ongoing clinical trials, which examines different locations in the lung (central and peripheral). This review discusses current indications, fractionations, challenges, and technical requirements for lung SBRT.

Oligometastatic Breast Cancer: How to Manage It?

Breast cancer (BC) is the most frequent cancer among women and represents the second leading cause of cancer-specific death. A subset of patients with metastatic breast cancer (MBC) presents limited disease, termed 'oligometastatic' breast cancer (OMBC). The oligometastatic disease can be managed with different treatment strategies to achieve long-term remission and eventually cure. Several approaches are possible to cure the oligometastatic disease: locoregional treatments of the primary tumor and of all the metastatic sites, such as surgery and radiotherapy; systemic treatment, including target-therapy or immunotherapy, according to the biological status of the primary tumor and/or of the metastases; or the combination of these approaches. Encouraging results involve local ablative options, but these trials are limited by being retrospective and affected by selection bias. Systemic therapy, e.g., the use of CDK4/6 inhibitors for hormone receptor-positive (HR+)/HER-2 negative BC, leads to an increase of progression-free survival (PFS) and overall survival (OS) in all the subgroups, with favorable toxicity. Regardless of the lack of substantial data, this subset of patients could be treated with curative intent; the appropriate candidates could be mostly young women, for whom a multidisciplinary aggressive approach appears suitable. We provide a global perspective on the current treatment paradigms of OMBC.

Radiation in the Treatment of Oligometastatic and Oligoprogressive Disease: Rationale, Recent Data, and Research Questions

The use of local ablative therapy or metastasis-directed therapy is an emerging management paradigm in oligometastatic and oligoprogressive cancer. Recent randomized evidence has demonstrated that stereotactic ablative radiotherapy (SABR) targeting all metastatic deposits is tolerable and can improve progression-free and overall survival. While SABR is noninvasive, minimally toxic, and generally safe, rare grade 5 events have been reported. Given this and recognizing the often-uncertain prognosis of patients with metastatic disease, equipoise persists regarding the therapeutic window within which to deploy SABR for this indication. Ongoing phase III trials are aimed at validating the demonstrated safety, tolerability, and survival benefits while also refining patient selection, possibly with the aid of novel biomarkers. This narrative review of the role of SABR in oligometastatic and oligoprogressive disease summarizes recent randomized evidence and ongoing clinical trials, discusses our rationale for treatment and key management principles, and posits that SABR should be considered the preferred modality for multisite, metastasis-directed ablative therapy.

Management of colorectal cancer in the era of COVID-19: Challenges and suggestions

The Coronavirus (COVID-19) pandemic had a huge impact on all sectors around the world. In particular, the healthcare system has been subject to an enormous pressure that has surpassed its ability in many instances. Additionally, the pandemic has called for a review of our daily medical practices, including our approach to colorectal cancer management where treatment puts patients at high risk of virus exposure. Given their higher median age, patients are at an increased risk for severe symptoms and complications in cases of infection, especially in the setting of immunosuppression. Therefore, a review of the routine colorectal cancer practices is needed to minimize risk of exposure. Oncologists should weigh risk of exposure versus the patient's oncologic benefits when approaching management. In addition, treatment protocols should be modified to minimize hospital visits and admissions while maintaining the same treatment efficacy. In this review, we will focus on challenges that colorectal cancer patients face during the pandemic, while highlighting the priority in each case. We will also discuss the evidence for potential modifications to existing treatment plans that could reduce infectious exposure without compromising care. Finally, we will discuss the impact of the socio-economic difficulties faced by Lebanese patients due to a poor economy toppled by an unexpected pandemic.

Efficacy of Local Therapy for Oligometastatic Hepatocellular Carcinoma: A Propensity Score Matched Analysis

Purpose

With respect to various solid cancers, patients with oligometastasis may benefit from local therapy. However, this approach is not widely accepted for hepatocellular carcinoma. This study investigated the efficacy of local therapy for oligometastatic lesions in patients with hepatocellular carcinoma.

Patients and Methods

The study included 69 hepatocellular carcinoma patients presenting with oligometastasis to the lung. Characteristics of the patients and treatment options for metastatic lesions were reviewed, and a survival analysis was performed. After propensity score matching, overall survival and progression-free survival were calculated from the time of pulmonary metastasis detection. Factors predicting prognosis were analyzed using a multivariate Cox regression analysis.

Results

After propensity score matching, 58 patients with Child-Pugh grade A disease were selected. Among them, 22 patients were treated with systemic therapy alone while 36 patients received local therapy or a combination of local and systemic therapies for metastatic lesions. Survival rates were higher in patients receiving local therapy than in those receiving systemic therapy (2-year overall survival rate, 66.6 vs 31.2%, p<0.001; 2-year progression-free survival rate, 47.0 vs 10.6%, p=0.005). In the multivariate Cox regression analysis, alpha-fetoprotein levels less than 400 ng/mL and the use of local therapy for metastatic lesions were found to be significant favorable prognostic factors.

Conclusion

Local therapy for metastatic lesions improved the oncologic outcomes of patients with hepatocellular carcinoma with pulmonary oligometastasis.

Role of 18F-Fluciclovine and Prostate-Specific Membrane Antigen PET/CT in Guiding Management of Oligometastatic Prostate Cancer: AJR Expert Panel Narrative Review

Twenty-five years ago, oligometastatic disease was proposed as an intermediary clinical state of cancer with unique implications for therapies that may impact cancer evolution and patient outcome. Identification of limited metastases that are potentially amenable to targeted therapies fundamentally depends on the sensitivity of diagnostic tools, including new-generation imaging methods. For men with biochemical recurrence after definitive therapy of the primary prostate cancer, PET/CT using either the FDA-approved radiolabeled amino acid analogue ¹⁸F-fluciclovine or investigational radiolabeled agents targeting prostate-specific membrane antigen (PSMA) enables identification of early metastases at lower serum PSA levels than was previously feasible using conventional imaging. Evidence supports PSMA PET/CT as the most sensitive imaging modality available for identifying disease sites in oligometastatic prostate cancer. PSMA PET/CT will likely become the modality of choice after regulatory approval and will drive the development of trials of emerging metastasis-directed therapies such as stereotactic ablative body radiation and radioguided surgery. Indeed, numerous ongoing or planned clinical trials are studying advances in management of oligometastatic prostate cancer based on this heightened diagnostic capacity. In this rapidly evolving clinical environment, radiologists and nuclear medicine physicians will play major roles in facilitating clinical decision making and management of patients with oligometastatic prostate cancer.

Stereotactic body radiation therapy: A good dance partner of oligometastatic non-small cell lung cancer to the sound of SINDAS study

The European Organization for Research on Treatment of Cancer Research published a consensus statement to establish the key criteria to define oligometastatic disease (OMD). According to those criteria, all lesions (both primary and metastatic) should be amenable to radical intent treatment with acceptable toxicity. Several retrospective studies have shown that adding local ablative therapy to the treatment of OMD improves outcomes; however, due to the diverse selection criteria and treatment strategies used in those studies, it is difficult to compare directly results to draw definitive conclusions. In recent years, prospective phase II trials, such as the SABR-COMET and "Oligomez" trials, have shown that stereotactic body radiation therapy (SBRT) improves outcomes in patients with OMD. More recently, interim results of the randomised phase 3 SINDAS trial were reported at the annual meeting of the American Society of Clinical Oncology 2020 demonstrating that upfront SBRT added to systemic treatment with tyrosine kinase inhibitors yielded a significant benefit in both progression-free survival and overall survival in patients with epidermal growth factor receptor-mutant oligometastatic non-small cell lung cancer. In the present editorial, we review the definition and historical context of advanced non-small cell lung cancer with OMD. In addition, we review the scientific evidence for local ablative therapy and SBRT and discuss the results of recently published prospective studies. We also discuss in depth the results of the SINDAS study, including the strengths and weaknesses of the study and the barriers to extrapolating these results to routine clinical practice.

Single‐fraction image‐guided robotic radiosurgery efficiently controls local prostate cancer recurrence after radical prostatectomy

Purpose

To assess the therapeutic potential of single‐fraction robotic stereotactic ablative body radiotherapy (SABR) in patients with locally recurrent prostate cancer (PC) after radical prostatectomy (RP).

Materials and methods

We included 35 patients with biochemical failure after RP with single‐site local recurrence in the prostate bed diagnosed by PSMA PET/CT. About 20/35 pts had previously received post‐surgical adjuvant radiation therapy.

High‐resolution multiparametric magnetic resonance imaging (mpMRI) for exact visualization of tumor tissue was performed at 1.5 (n = 23; Siemens Magnetom Aera) or 3 Tesla (n = 12; Siemens Magnetom VIDA, Siemens Healthineers, Erlangen, Germany). Using the MRI and PET/CT dataset for planning, SABR was carried out after ultrasound‐guided placement of a single gold fiducial marker at the site of tumor recurrence using a CyberKnife M6 unit (Accuray Inc., Sunnyvale, USA). Due to the high diagnostic accuracy of PSMA PET/CT and mpMRI, pre‐SABR biopsy of tumor tissue was not deemed necessary. PSMA PET/CT performed in median 88 days before SABR confirmed the absence of distant metastases. MpMRI was performed at a median of 22 days prior to the intervention. SABR was performed in a single fraction with a dose of 20 (5/35), 21 (27/35) or 22 (3/35) Gy. Follow‐up serum PSA was measured every 3 months thereafter.

Results

Median patient age was 72 years (57‐80 years) and median time from RP to SABR was 96.8 months (IQR, 69.3‐160.2). Median serum PSA before SABR was 1.38 ng/mL (IQR 0.75‐2.72). At 3 months, median PSA had dropped significantly in 27/35 patients to a median of 0.35 ng/mL (IQR 0.25‐0.68). At 6 months, 30/35 patients showed biochemical response to SABR, while five patients were progressing: three had systemic disease on PSMA PET/CT, while two patients had rising PSA values without a visible correlate on PET/CT. The median follow‐up time was 16 months. Grade 1 genitourinary (GU) toxicity was reported in 3/35 patients (9%) and grade 1 gastrointestinal (GI) toxicity in 2/35 patients (6%), respectively.

Conclusion

SABR is an efficient new treatment option in the management of single‐site local recurrent PC without the evidence of systemic disease; due to its very low toxicity, it is an alternative to surgical re‐treatment or other focal therapies. It can significantly delay the onset of androgen deprivation therapy (ADT) in biochemical failure after radical prostatectomy.

Stereotactic body radiotherapy in the management of oligometastatic and recurrent biliary tract cancer: single-institution analysis of outcome and toxicity

INTRODUCTION

Biliary tract cancers (BTC) are rare malignancies arising from biliary system. Systemic therapy is the cornerstone for stage IV disease, with poor overall survival (OS). Evidence is lacking about safety and efficacy of local ablative treatments, such as surgery and stereotactic body radiotherapy (SBRT) in the context of metastatic BTC (mBTC).

MATERIALS AND METHODS

We retrospectively analyzed clinical outcomes for a cohort of mBTC patients treated with SBRT for oligometastatic disease. Inclusion criteria were 1-5 distant metastases; SBRT with a dose/fraction of a least 5 Gy to a biological effective dose (BED) of at least 40 Gy considering an α/β of 10 Gy. Analyzed outcomes included local control (LC), distant progression-free survival (DPFS), PFS, and OS.

RESULTS

51 patients meeting the inclusion criteria. Primary tumor sites were intrahepatic cholangiocarcinoma (35%), extrahepatic cholangiocarcinoma (31%), ampullary adenocarcinoma (20%), gallbladder adenocarcinoma (14%). 21 patients were treated on liver lesions, 17 on nodal metastasis, 5 patients on lung lesions, 4 patients on recurrence along the extrahepatic bile duct. After a median follow-up of 14 months median OS was 13.7 months, 1- and 2-year OS were 58% and 41%, respectively. Node and lung as metastatic sites were associated with a longer OS (p < 0.001). Median LC was 26.8 months, and intrahepatic cholangiocarcinoma was associated with longer LC (p = 0.036). Median DPFS was 11 months, with 1- and 2-year DPFS of 48% and 27.8%, respectively. Ten patients reported grade 1-2 toxicity and 2 cases of acute G3 biliary obstruction.

CONCLUSIONS

Stereotactic body radiotherapy (SBRT) is feasible in the context of mBTC. OS and PFS results are promising, considering that our patients were heavily pre-treated with systemic therapy. Patients with nodal or lung relapse have better prognosis. Distant relapses remain the main pattern of failure, but treatment of all metastatic sites seems to improve DMFS.

Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers: Long-Term Results of the SABR-COMET Phase II Randomized Trial

PURPOSE

The oligometastatic paradigm hypothesizes that patients with a limited number of metastases may achieve long-term disease control, or even cure, if all sites of disease can be ablated. However, long-term randomized data that test this paradigm are lacking.

METHODS

< .20 indicates a positive trial). Secondary end points included progression-free survival (PFS), toxicity, and quality of life (QOL). Herein, we present long-term outcomes from the trial.

RESULTS

= .001). There were no new grade 2-5 adverse events and no differences in QOL between arms.

CONCLUSION

With extended follow-up, the impact of SABR on OS was larger in magnitude than in the initial analysis and durable over time. There were no new safety signals, and SABR had no detrimental impact on QOL.

Stereotactic Body Radiotherapy for Oligometastatic Prostate Cancer Recurrence: A Meta-analysis

PURPOSE

The purpose of this study was to evaluate the treatment efficacy of stereotactic body radiotherapy (SBRT) in oligometastatic prostate cancer recurrence and to assess whether there is any relationship between biologically effective dose (BED) and local control (LC).

MATERIALS AND METHODS

Eligible studies were identified on Medline, Embase, and the Cochrane Library, and the proceedings of annual meetings through May 2019 were also identified. A meta-regression analysis was performed to assess whether there is a relationship between BED and LC. In the univariate analysis, studies were separated by the study design, the number of metastatic sites, the site of metastases, radiotherapy machine, and prostate-specific antigen level at the time of SBRT. A P-value <0.05 was considered significant.

RESULTS

Twenty-three observational studies with a total of 1441 lesions treated were included in the meta-analysis. The proportional rate of LC, progression-free survival, and androgen deprivation-free survival was 0.976 (95% confidence interval [CI]: 0.96-0.98), 0.413 (95% CI: 0.378-0.477), and 20.1 months (95% CI: 14.5-25.6), respectively. In the meta-regression, a linear relationship between BED and LC was detected (P=0.017). Stratifying the BED into 3 levels (BED<100 Gy3, BED 100 to 130 Gy3, and BED>130 Gy3), a significant difference was observed between BED<100 Gy3 (LC=88%) versus BED>100 Gy3 (LC=96%). The rate of any acute and late grade ≥2 toxicity was 1.3% and 1.2%, respectively.

CONCLUSIONS

The LC rate with SBRT was excellent with minimal severe acute/late toxicity. Our data suggest a dose relationship between BED and LC, with BED >100 Gy3 resulting in better rates of LC.

Characterisation and classification of oligometastatic disease: a European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus recommendation

Oligometastatic disease has been proposed as an intermediate state between localised and systemically metastasised disease. In the absence of randomised phase 3 trials, early clinical studies show improved survival when radical local therapy is added to standard systemic therapy for oligometastatic disease. However, since no biomarker for the identification of patients with true oligometastatic disease is clinically available, the diagnosis of oligometastatic disease is based solely on imaging findings. A small number of metastases on imaging could represent different clinical scenarios, which are associated with different prognoses and might require different treatment strategies. 20 international experts including 19 members of the European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer OligoCare project developed a comprehensive system for characterisation and classification of oligometastatic disease. We first did a systematic review of the literature to identify inclusion and exclusion criteria of prospective interventional oligometastatic disease clinical trials. Next, we used a Delphi consensus process to select a total of 17 oligometastatic disease characterisation factors that should be assessed in all patients treated with radical local therapy for oligometastatic disease, both within and outside of clinical trials. Using a second round of the Delphi method, we established a decision tree for oligometastatic disease classification together with a nomenclature. We agreed oligometastatic disease as the overall umbrella term. A history of polymetastatic disease before diagnosis of oligometastatic disease was used as the criterion to differentiate between induced oligometastatic disease (previous history of polymetastatic disease) and genuine oligometastatic disease (no history of polymetastatic disease). We further subclassified genuine oligometastatic disease into repeat oligometastatic disease (previous history of oligometastatic disease) and de-novo oligometastatic disease (first time diagnosis of oligometastatic disease). In de-novo oligometastatic disease, we differentiated between synchronous and metachronous oligometastatic disease. We did a final subclassification into oligorecurrence, oligoprogression, and oligopersistence, considering whether oligometastatic disease is diagnosed during a treatment-free interval or during active systemic therapy and whether or not an oligometastatic lesion is progressing on current imaging. This oligometastatic disease classification and nomenclature needs to be prospectively evaluated by the OligoCare study.

Pain REduction with bone metastases STereotactic radiotherapy (PREST): A phase III randomized multicentric trial

Background

Palliative antalgic treatments represent an issue for clinical management and a challenge for scientific research. Radiotherapy (RT) plays a central role. Techniques such as stereotactic body radiotherapy (SBRT) were largely investigated in several phase 2 studies with good symptom response, becoming widely adopted. However, evidence from randomized, direct comparison of RT and SBRT is still lacking.

Methods/design

The PREST trial was designed as an interventional study without medicinal treatment. It is a phase 3, open-label, multicentric trial randomized 1:1. Inclusion criteria include painful spinal bone metastases presenting with a pain level > 4 (or > 1 if being treated with an analgesic) on the Numeric Rating Scale (NRS); expected intermediate/high prognosis (greater than 6 months) according to the Mizumoto prognostic score; low spine instability neoplastic score (SINS) sores (< 7); magnetic resonance imaging (MRI) assessment of the bulky lesion. Patients will be assigned to either standard conventional radiotherapy involving 4 Gy × 5 fractions (fx) to the whole involved vertebra or SBRT by intensity modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) involving 7 Gy × 3 fx to the whole involved vertebra + 10 Gy × 3 fx on the macroscopic lesion (gross tumor volume (GTV)). In the experimental arm, the GTV will be contoured by registration with baseline MRI.

Discussion

The primary endpoint is overall pain reduction, defined in terms of variation between baseline and 3-month evaluation; pain will be measured using the NRS. Secondary endpoints include pain control duration; retreatment rates (after a minimum interval of 1 month); local control assessed with RECIST criteria; symptom progression free survival; progression-free survival; overall survival; and quality of life (at 0, 30, and 90 days). Accrual of 330 lesions is planned. The experimental arm is expected to have an improvement in overall pain response rates of 15% with respect to the standard arm (60% according to Chow et al. (Int J Radiat Oncol Biol Phys. 82(5):1730–7, 2012)).

Trial registration

ClinicalTrials.gov, NCT03597984. Registered on July 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3676-x) contains supplementary material, which is available to authorized users.

Local ablative radiotherapy for oligometastatic non-small cell lung cancer

In metastatic non-small cell lung cancer (NSCLC), the role of radiotherapy (RT) has been limited to palliation to alleviate the symptoms. However, with the development of advanced RT techniques, recent advances in immuno-oncology therapy targeting programmed death 1 (PD-1) and programmed death ligand 1 (PD-L1) and targeted agents for epidermal growth factor receptor (EGFR) mutation or anaplastic lymphoma kinase (ALK) translocation allowed new roles of RT in these patients. Within this metastatic population, there is a subset of patients with a limited number of sites of metastatic disease, termed as oligometastasis that can achieve long-term survival from aggressive local management. There is no consensus on the definition of oligometastasis; however, most clinical trials define oligometastasis as having 3 to 5 metastatic lesions. Recent phase II randomized clinical trials have shown that ablative RT, including stereotactic ablative body radiotherapy (SABR) and hypofractionated RT, to primary and metastatic sites improved progression-free survival (PFS) and overall survival (OS) in patients with oligometastatic NSCLC. The PEMBRO-RT study, a randomized phase II study comparing SABR prior to pembrolizumab therapy and pembrolizumab therapy alone, revealed that the addition of SABR improved the overall response, PFS, and OS in patients with advanced NSCLC. The efficacy of RT in oligometastatic lung cancer has only been studied in phase II studies; therefore, large-scale phase III studies are needed to confirm the benefit of local ablative RT in patients with oligometastatic NSCLC. Local intensified RT to primary and metastatic lesions is expected to become an important treatment paradigm in the near future in patients with metastatic lung cancer.

Stereotactic ablative radiotherapy for the comprehensive treatment of 4-10 oligometastatic tumors (SABR-COMET-10): study protocol for a randomized phase III trial

Background

Stereotactic ablative radiotherapy (SABR) has emerged as a new treatment option for patients with oligometastatic disease. SABR delivers precise, high-dose, hypofractionated radiotherapy, and achieves excellent rates of local control for primary tumors or metastases. A recent randomized phase II trial evaluated SABR in a group of patients with a small burden of oligometastatic disease (mostly with 1–3 metastatic lesions), and found that SABR was associated with benefits in progression-free survival and overall survival. The goal of this phase III trial is to assess the impact of SABR in patients with 4–10 metastatic cancer lesions.

Methods

One hundred and fifty-nine patients will be randomized in a 1:2 ratio between the control arm (consisting of standard of care palliative-intent treatments), and the SABR arm (consisting of standard of care treatment + SABR to all sites of known disease). Randomization will be stratified by two factors: histology (Group 1: prostate, breast, or renal; Group 2: all others), and type of pre-specified systemic therapy (Group 1: immunotherapy/targeted; Group 2: cytotoxic; Group 3: observation). SABR is to be completed within 2 weeks, allowing for rapid initiation of systemic therapy. Recommended SABR doses are 20 Gy in 1 fraction, 30 Gy in 3 fractions, or 35 Gy in 5 fractions, chosen to minimize risks of toxicity. The primary endpoint is overall survival, and secondary endpoints include progression-free survival, time to development of new metastatic lesions, quality of life, and toxicity. Translational endpoints include assessment of circulating tumor cells, cell-free DNA, and tumor tissue as prognostic and predictive markers, including assessment of immunological predictors of response and long-term survival.

Discussion

This study will provide an assessment of the impact of SABR on clinical outcomes and quality of life, to determine if long-term survival can be achieved for selected patients with 4–10 oligometastatic lesions.

Trial registration

Clinicaltrials.gov identifier: NCT03721341. Date of registration: October 26, 2018.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5977-6) contains supplementary material, which is available to authorized users.

A Review of Ongoing Trials of Stereotactic Ablative Radiotherapy for Oligometastatic Cancers: Where Will the Evidence Lead?

Purpose: The oligometastatic state is a proposed entity between localized cancer and widely metastatic disease, comprising an intermediate subset of metastatic cancer patients. Most data to support locally-directed treatment, such as stereotactic ablative radiotherapy (SABR), for oligometastases are from retrospective institutional reports. Following the success of a recently completed and reported phase II trial demonstrating important clinical outcomes, herein we review the current landscape of ongoing clinical trials in this context. Materials and methods: A review of currently activated and registered clinical trials was performed using the clinicaltrials.gov database from inception to February 2019. A search of actively recruiting trials, using the key words oligometastases, SABR, and various related terms was performed. Search results were independently reviewed by two investigators, with discrepancies settled by a third. Data abstracted from identified studies included study type, primary disease site, oncologic endpoints, and inclusion/exclusion criteria. Results: Of the initial 216 entries identified, 64 met our review eligibility criteria after full-text review. The most common study type was a phase II clinical trial (n = 35, 55%) with other study designs ranging from observational registry trials to phase III randomized controlled trials (RCTs). A minority of trials were randomized in design (n = 17, 27%). While most studies allowed for metastases from multiple primary disease sites (n = 22, 34%), the most common was prostate (n = 13, 15%), followed by breast, gastrointestinal, non-small cell lung cancer (NSCLC), and renal (n = 6, 9% each). In studies with a solitary target site, the most common was liver (n = 6, 9%) followed by lung (n = 3, 5%). The most common primary endpoints were progression-free survival (PFS) (n = 20, 31%) and toxicity (n = 10, 16%). A combined strategy of systemic therapy and SABR was an emerging theme (n = 23, 36%), with more recent studies specifically evaluating SABR and immunotherapy (n = 9, 14%). Conclusion: The safety and efficacy of SABR as oligometastasis-directed treatment is increasingly being evaluated within prospective clinical trials. These data are awaited to compliment the abundance of existing observational studies and to guide clinical decision-making.

Utilization of stereotactic ablative radiotherapy in oligometastatic & oligoprogressive skeletal metastases: Results and pattern of failure

AIM

To evaluate the outcome and toxicities of stereotactic ablative radiotherapy (SABR) for skeletal metastasis in a tertiary cancer center.

METHODS

This is a retrospective review of 22 patients treated with SABR for skeletal metastases for oligometastases (OM) or oligoprogression (OP) since October 2012. There are a total of 27 treatments with 20 spinal and seven non-spinal metastases. Treatment outcome including local control (LC), progression-free survival (PFS), overall survival (OS), pain control, treatment-related toxicity and failure pattern are described. Patients are assessed by interval computed tomography (CT), positron emission tomography-CT, magnetic resonance imaging or bone scintigraphy by physicians' discretion. Toxicities are graded by common toxicities criteria version 4.03.

RESULT

The median age of the patients is 64 years. Primary sites include lung (50%), breast (32%), nasopharynx (9%), prostate (4.5%) and colon (4.5%). Twelve patients with OM and 10 with OP are included. Dose to most spinal and non-spinal metastases is 35 and 50 Gy, respectively, in five fractions. With a median follow up of 15.6 months, there are three local failures (1-year LC 91.2%). The median PFS and OS are 10.1 and 37.3 months, while PFS of OP and OM group is 6.6 and 10.6 months, respectively. Two-third of symptomatic patients have at least 1-year complete pain control. There are two vertebral fractures and one grade 3 esophagitis.

CONCLUSION

Our series shows excellent LC of SABR to skeletal metastases with limited toxicities in OM and OP diseases. However, its benefit of survival warrants further studies.

Oligometastases in prostate cancer: Ablative treatment

Technological advances in radiotherapy have led to the introduction of techniques such as stereotactic body radiation therapy (SBRT), allowing the administration of ablative doses. The hypothesis that oligometastatic disease may be cured through local eradication therapies has led to the increasing use of SBRT in patients with this type of disease. At the same time, scientific advances are being made to allow the confirmation of clinically suspected oligometastatic status at molecular level. There is growing interest in identifying patients with oligometastatic prostate cancer (PCa) who may benefit from curative intent metastasis-directed therapy, including SBRT. The aim is to complement, replace or delay the introduction of hormone therapy or other systemic therapies. The present review aims to compile the evidence from the main ongoing studies and results on SBRT in relation to oligometastatic PCa; examine aspects where gaps in knowledge or a lack of consensus persist (e.g., optimum schemes, response assessment, identification and diagnosis of oligometastatic patients); and document the lack of first-level evidence supporting the use of such techniques.

Precision medicine for locally advanced breast cancer: frontiers and challenges in Latin America

Advances in high-throughput technologies and their involvement in the 'omics' of cancer have made possible the identification of hundreds of biomarkers and the development of predictive and prognostic platforms that model the management of cancer from evidence-based medicine to precision medicine. Latin America (LATAM) is a region characterised by fragmented healthcare, high rates of poverty and disparities to access to a basic standard of care not only for cancer but also for other complex diseases. Patients from the public setting cannot afford targeted therapy, the facilities offering genomic platforms are scarce and the use of high-precision radiotherapy is limited to few facilities. Despite the fact that LATAM oncologists are well-trained in the use of genomic platforms and constantly participate in genomic projects, a medical practice based in precision oncology is a great challenge and frequently limited to private practice. In breast cancer, we are waiting for the results of large basket trials to incorporate the detection of actionable mutations to select targeted treatments, in a similar way to the management of lung cancer. On the other hand and paradoxically, in the 'one fit is not for all' era, clinical and genomic studies continue grouping our patients under the single label 'Latin American' or 'Hispanic' despite the different ancestries and genomic backgrounds seen in the region. More regional cancer genomic initiatives and public availability of this data are needed in order to develop more precise oncology in locally advanced breast cancer.

Radiotherapy for recurrent prostate cancer: 2018 Recommendations of the Australian and New Zealand Radiation Oncology Genito-Urinary group

The management of patients with biochemical, local, nodal, or oligometastatic relapsed prostate cancer has become more challenging and controversial. Novel imaging modalities designed to detect recurrence are increasingly used, particularly PSMA-PET scans in Australia, New Zealand and some European countries. Imaging techniques such as MRI and PET scans using other prostate cancer-specific tracers are also being utilised across the world. The optimal timing for commencing salvage treatment, and the role of local and/or systemic therapies remains controversial. Through surveys of the membership, the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group (FROGG) identified wide variation in the management of recurrent prostate cancer. Following a workshop conducted in April 2017, the FROGG management committee reviewed the literature and developed a set of recommendations based on available evidence and expert opinion, for the appropriate investigation and management of recurrent prostate cancer. These recommendations cover the role and timing of post-prostatectomy radiotherapy, the management of regional nodal metastases and oligometastases, as well as the management of local prostate recurrence after definitive radiotherapy.