•Metastasis-directed radiotherapy (MDRT) has the potential to prolong survival.•Definitions and reporting of oligometastatic disease (OMD) are heterogeneous.•OMD is typically based on the ...imaging-detected number of metastases, but definitions in the literature are inconsistent and warrant further study. No formal clinical or molecular biomarkers currently exist to aid classification as OMD.•Currently no clinical or molecular biomarkers exist to aid classification of OMD.•Advanced technologies are mandatory to guarantee safe MDRT and improve outcome.•Consensus for extra-cranial OMD defines maximum 5 metastatic lesions off-protocol.
Recognizing the rapidly increasing interest and evidence in using metastasis-directed radiotherapy (MDRT) for oligometastatic disease (OMD), ESTRO and ASTRO convened a committee to establish consensus regarding definitions of OMD and define gaps in current evidence.
A systematic literature review focused on curative intent MDRT was performed in Medline, Embase and Cochrane. Subsequent consensus opinion, using a Delphi process, highlighted the current state of evidence and the limitations in the available literature.
Available evidence regarding the use of MDRT for OMD mostly derives from retrospective, single-centre series, with significant heterogeneity in patient inclusion criteria, definition of OMD, and outcomes reported. Consensus was reached that OMD is largely independent of primary tumour, metastatic location and the presence or length of a disease-free interval, supporting both synchronous and metachronous OMD. In the absence of clinical data supporting a maximum number of metastases and organs to define OMD, and of validated molecular biomarkers, consensus supported the ability to deliver safe and clinically meaningful radiotherapy with curative intent to all metastatic sites as a minimum requirement for defining OMD in the context of radiotherapy. Systemic therapy induced OMD was identified as a distinct state of OMD. High-resolution imaging to assess and confirm OMD is crucial, including brain imaging when indicated. Minimum common endpoints such as progression-free and overall survival, local control, toxicity and quality-of-life should be reported; uncommon endpoints as deferral of systemic therapy and cost were endorsed.
While significant heterogeneity exists in the current OMD definitions in the literature, consensus was reached on multiple key questions. Based on available data, OMD can to date be defined as 1–5 metastatic lesions, a controlled primary tumor being optional, but where all metastatic sites must be safely treatable. Consistent definitions and reporting are warranted and encouraged in ongoing trials and reports generating further evidence to optimize patient benefits.
Although surgery is the standard of care for resectable pancreatic cancer (PC), standard-dose chemoradiation therapy and chemotherapy alone are suitable for patients with unresectable disease. ...Stereotactic body radiation therapy (SBRT) is an alternative, focused local therapy that delivers high radiation doses within a few fractions to the cancer, sparing the surrounding critical tissue. We performed a systematic review and pooled analysis of published trials to evaluate the efficacy and safety of this emerging treatment modality.
We searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, SCOPUS, the Web of Science, and CINAHL for publications regarding SBRT for locally advanced PC. The 1-year overall survival (OS) rate was the primary endpoint, and the median OS, 2-year OS rate, 1-year locoregional control (LRC) rate, and grade 3 to 4 toxicities were the secondary endpoints. A multivariate random-effects meta-analysis was performed to calculate the aggregated OS rates at 1 and 2 years and the 1-year LRC rate.
A total of 19 studies, encompassing 1009 patients, were included in the present analysis. The pooled 1-year OS was 51.6% in 13 trials with data available. The median OS ranged from 5.7 to 47 months (median 17). The LRC rate at 1 year was 72.3%. Overall, the occurrence of severe adverse events did not exceed 10%. LRC appeared to correlate with the total SBRT dose and the number of fractions.
The advantages of SBRT in terms of treatment time, satisfactory OS, and LRC indicate that it is an effective option for inoperable PC. However, a definitive validation of this treatment modality in large randomized studies is required, owing to the nonrandomized nature of the included studies and the limitations of small single-center series that include mixed populations.
While surgery is the preferred option for isolated, operable liver metastases from colorectal cancer (CRC), ablative techniques are endorsed for medically or technically inoperable lesions. ...Stereotactic body radiotherapy (SBRT) is an alternative ablative local therapy that delivers high RT doses in a few fractions to the cancer, sparing surrounding critical tissue. We have performed a systematic review of published trials to evaluate the efficacy of SBRT as a primary modality therapy for CRC liver oligometastases.
We searched the Cochrane Central Register of Controlled Trials, Pubmed, and EMBASE for publications regarding SBRT for CRC liver metastases. Overall survival (OS: median, 1- and 2-year OS %) was the primary endpoint, and median PFS and one- and two-year local control (LC) were the secondary endpoints. A random-effect model pooled-analysis was performed to calculate the aggregated OS rates at 1 and 2 years as well as the one- and two-year LC.
A total of 18 studies, encompassing 656 patients, were included in the analysis. The pooled one- and two-year OS were 67.18% (95% CI, 42.1–92.2) and 56.5% (95% CI, 36.7–76.2), respectively. Median PFS and OS were 11.5 and 31.5 months. The pooled one-year LC was 67% (95% CI, 43.8–90.2), while the pooled two-year LC was 59.3% (95% CI, 37.2–81.5). Correlation analysis revealed a moderate/poor linear relationship between the SBRT (BED10) dose and LC (p = 0.001, R = 0.47)/OS (p = 0.001, R = 0.29) at 2 years. Mild-moderate and severe liver toxicity were 30.7% and 8.7%.
SBRT for liver oligometastases is an effective option for patients with advanced CRC, with encouraging local control and survival. However, a definitive validation in large randomised studies is required, due to the retrospective or non-randomised nature of the included studies and the limitations of series with different doses/schedules of treatment.
To evaluate the feasibility of high-dose stereotactic body radiation therapy (SBRT) in the treatment of unresectable liver metastases.
Patients with 1 to 3 liver metastases, with maximum individual ...tumor diameters less than 6 cm and a Karnofsky Performance Status of at least 70, were enrolled and treated by SBRT on a phase 2 clinical trial. Dose prescription was 75 Gy on 3 consecutive days. SBRT was delivered using the volumetric modulated arc therapy by RapidArc (Varian, Palo Alto, CA) technique. The primary end-point was in-field local control. Secondary end-points were toxicity and survival.
Between February 2010 and September 2011, a total of 61 patients with 76 lesions were treated. Among the patients, 21 (34.3%) had stable extrahepatic disease at study entry. The most frequent primary sites were colorectal (45.9%) and breast (18%). Of the patients, 78.7% had 1 lesion, 18.0% had 2 lesions, and 3.3% had 3 lesions. After a median of 12 months (range, 2-26 months), the in-field local response rate was 94%. The median overall survival rate was 19 months, and actuarial survival at 12 months was 83.5%. None of the patients experienced grade 3 or higher acute toxicity. No radiation-induced liver disease was detected. One patient experienced G3 late toxicity at 6 months, resulting from chest wall pain.
SBRT for unresectable liver metastases can be considered an effective, safe, and noninvasive therapeutic option, with excellent rates of local control and a low treatment-related toxicity.
Objectives
To evaluate the feasibility and efficacy of stereotactic body radiation therapy (SBRT) in the treatment of hepatocellular carcinoma (HCC) unsuitable for standard loco-regional therapies.
...Materials and methods
Patients with 1–3 inoperable HCC lesions with diameter ≤6 cm were treated by SBRT. According to lesions size and liver function, two prescription regimens were adopted: 48–75 Gy in three fractions or 36–60 Gy in six fractions. SBRT was delivered using the volumetric modulated arc therapy technique with flattening filter-free photon beams. The primary end points of this study were in-field local control (LC) and toxicity. Secondary end points were overall survival (OS) and progression-free survival (PFS).
Results
Forty-three patients with 63 HCC lesions were irradiated. All patients had Child–Turcotte–Pugh class A or B disease. Thirty lesions (48 %) were treated with 48–75 Gy in three consecutive fractions, and 33 (52 %) received 36–60 Gy in six fractions. Median follow-up was 8 months (range 3–43 months). Actuarial LC at 6, 12 and 24 months was 94.2 ± 3.3, 85.8 ± 5.5 and 64.4 ± 11.5 %, respectively. A biological equivalent dose (BED) >100 Gy and GTV size were significant prognostic factors for LC in univariate analysis (
p
< 0.001 and
p
< 0.02). Median OS was 18.0 ± 5.8 months. Actuarial OS at 6, 12 and 24 months was 91.1 ± 4.9, 77.9 ± 8.2 and 45.3 ± 14.0 %, respectively. Univariate analysis showed that OS is correlated with LC (
p
< 0.04), BED >100 (
p
< 0.05) and cumulative gross tumor volume GTV <5 cm (
p
< 0.04). Median PFS was 8 months, with a 1-year PFS rate of 41 %. A significant (≥grade 3) toxicity was observed in seven patients (16 %) 2–6 months after the completion of the treatment. No classic radiation-induced liver disease was observed.
Conclusion
Stereotactic body radiation therapy is a safe and effective therapeutic option for HCC lesions unsuitable to standard loco-regional therapies, with acceptable local control rates and low treatment-related toxicity. The significant correlation between LC and higher doses and between LC and OS supports the clinical value of SBRT in these patients.
To appraise the ability of a radiomics based analysis to predict local response and overall survival for patients with hepatocellular carcinoma.
A set of 138 consecutive patients (112 males and 26 ...females, median age 66 years) presented with Barcelona Clinic Liver Cancer (BCLC) stage A to C were retrospectively studied. For a subset of these patients (106) complete information about treatment outcome, namely local control, was available. Radiomic features were computed for the clinical target volume. A total of 35 features were extracted and analyzed. Univariate analysis was used to identify clinical and radiomics significant features. Multivariate models by Cox-regression hazards model were built for local control and survival outcome. Models were evaluated by area under the curve (AUC) of receiver operating characteristic (ROC) curve. For the LC analysis, two models selecting two groups of uncorrelated features were analyzes while one single model was built for the OS analysis.
The univariate analysis lead to the identification of 15 significant radiomics features but the analysis of cross correlation showed several cross related covariates. The un-correlated variables were used to build two separate models; both resulted into a single significant radiomic covariate: model-1: energy p < 0.05, AUC of ROC 0.6659, C.I.: 0.5585-0.7732; model-2: GLNU p < 0.05, AUC 0.6396, C.I.:0.5266-0.7526. The univariate analysis for covariates significant with respect to local control resulted in 9 clinical and 13 radiomics features with multiple and complex cross-correlations. After elastic net regularization, the most significant covariates were compacity and BCLC stage, with only compacity significant to Cox model fitting (Cox model likelihood ratio test p < 0.0001, compacity p < 0.00001; AUC of the model is 0.8014 (C.I. = 0.7232-0.8797)).
A robust radiomic signature, made by one single feature was finally identified. A validation phases, based on independent set of patients is scheduled to be performed to confirm the results.
Objectives
Temporal muscle thickness (TMT) is a surrogate marker of sarcopenia, correlated with survival expectancy in patients suffering from brain metastases and recurrent or treated glioblastoma. ...We evaluated the prognostic relevance of TMT measured on brain MRIs acquired at diagnosis in patients affected by glioblastoma.
Methods
We retrospectively enrolled 51 patients in our Institution affected by methylated MGMT promoter, IDH1–2 wild-type glioblastoma, who underwent complete surgical resection and subsequent radiotherapy with concomitant and maintenance temozolomide, from January 1, 2015, to April 30, 2017. The last clinical/radiological follow-up date was set to September 3, 2019. TMT was measured bilaterally on reformatted post-contrast 3D MPRAGE images, acquired on our 3-T scanner no more than 2 days before surgery. The median, 25th, and 75th percentile TMT values were identified and population was subdivided accordingly; afterwards, statistical analyses were performed to verify the association among overall survival (OS) and TMT, sex, age, and ECOG performance status.
Results
In our cohort, the median OS was 20 months (range 3–51). Patients with a TMT ≥ 8.4 mm (median value) did not show a statistically significant increase in OS (Cox regression model: HR 1.34, 95% CI 0.68–2.63,
p
= 0.403). Similarly, patients with a TMT ≥ 9.85 mm (fourth quartile) did not differ in OS compared to those with TMT ≤ 7 mm (first quartile). The statistical analyses confirmed a significant association among TMT and sex (
p
= 0.0186), but none for age (
p
= 0.642) and performance status (
p
= 0.3982).
Conclusions
In our homogeneous cohort of patients with glioblastoma at diagnosis, TMT was not associated with prognosis, age, or ECOG performance status.
Key Points
• Temporal muscle thickness (TMT) is a surrogate marker of sarcopenia and has been correlated with survival expectancy in patients suffering from brain metastases and recurrent or treated glioblastoma.
• We appraised the correlation among TMT and survival, sex, age at surgery, and performance status, measured on brain MRIs of patients affected by glioblastoma at diagnosis.
• TMT did not show any significant correlation with prognosis, age at surgery, or performance status, and its usefulness might be restricted only to patients with brain metastases and recurrent or treated glioblastoma.
To appraise the ability of a radiomics signature to predict clinical outcome after stereotactic body radiation therapy (SBRT) for pancreas carcinoma.
A cohort of 100 patients was included in this ...retrospective, single institution analysis. Radiomics texture features were extracted from computed tomography (CT) images obtained for the clinical target volume. The cohort of patients was randomly divided into two separate groups for the training (60 patients) and validation (40 patients). Cox regression models were built to predict overall survival and local control. The significant predictors at univariate analysis were included in a multivariate model. The quality of the models was appraised by means of area under the curve and concordance index.
A clinical-radiomic signature associated with Overall Survival (OS) was found significant in both training and validation sets (p = 0.01 and 0.05 and concordance index 0.73 and 0.75 respectively). Similarly, a signature was found for Local Control (LC) with p = 0.007 and 0.004 and concordance index 0.69 and 0.75. In the low risk group, the median OS and LC in the validation group were 14.4 and 28.6 months while in the high-risk group were 9.0 and 17.5 months respectively.
A CT based radiomic signature was identified which correlate with OS and LC after SBRT and allowed to identify low and high-risk groups of patients.
Purpose:
Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and ...to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis.
Methods:
Single point output factor measurement was acquired with a PTW microDiamond detector for 6 MV, 6 and 10 MV unflattened beams generated by a Varian TrueBeam STx equipped with high definition-MLC. Fields defined by jaw or MLC apertures were set; jaw-defined: 0.6 × 0.6, 0.8 × 0.8, 1 × 1, 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm2; MLC-defined: 0.5 × 0.5 cm2 to the maximum field defined by the jaw, with 0.5 cm stepping, and jaws set to: 2 × 2, 3 × 3, 4 × 4, 5 × 5, and 10 × 10 cm2. MU calculation was obtained with 1 mm grid in a virtual water phantom for the same fields, for AAA and Acuros algorithms implemented in the Varian eclipse treatment planning system (version 13.6). Configuration parameters as the effective spot size (ESS) and the dosimetric leaf gap (DLG) were varied to find the best parameter setting. Differences between calculated and measured doses were analyzed.
Results:
Agreement better than 0.5% was found for field sizes equal to or larger than 2 × 2 cm2 for both algorithms. A dose overestimation was present for smaller jaw-defined fields, with the best agreement, averaged over all the energies, of 1.6% and 4.6% for a 1 × 1 cm2 field calculated by AAA and Acuros, respectively, for a configuration with ESS = 1 mm for both X and Y directions for AAA, and ESS = 1.5 and 0 mm for X and Y directions for Acuros. Conversely, a calculated dose underestimation was found for small MLC-defined fields, with the best agreement averaged over all the energies, of −3.9% and 0.2% for a 1 × 1 cm2 field calculated by AAA and Acuros, respectively, for a configuration with ESS = 0 mm for both directions and both algorithms.
Conclusions:
For optimal setting applied in the algorithm configuration phase, the agreement of Acuros calculations with measurements could achieve the 3% for MLC-defined fields as small as 0.5 × 0.5 cm2. Similar agreement was found for AAA for fields as small as 1 × 1 cm2.
Adrenal metastases occur in 15–35% of oncological patients. Surgery is the first treatment option. Stereotactic body radiotherapy (SBRT) has been largely explored in oligometastatic patients unfit ...for surgery, representing an effective and non-invasive local treatment. The results of a multi-institutional experience of SBRT on adrenal metastases in the oligorecurrent or oligoprogressive setting are herein reported. We collected data of adrenal gland metastases treated with SBRT in three Italian centers from 2010 to 2020. End-points of the present study were: Overall survival (OS), Local control of treated metastases (LC), Progression free survival (PFS), and toxicity. 149 adrenal gland metastases were treated with SBRT in 142 patients. The most common primary tumor was lung cancer (58.4%), followed by kidney cancer (9.4%). Median lesion’s volume was 28.5 cm
3
(2.5–323.4). The median SBRT dose was 40 Gy (10–60). Median follow-up was 14.4 months. One- and two-year OS were 72.3% and 53.5%. At univariate analysis performance status correlated with survival (HR 1.57, p = 0.006). One- and two-year LC were 85.4% and 79.2%, with lung primary tumor (HR 0.33, p = 0.021) and BED10 (HR 0.97, p = 0.036) significant independent factors. One- and two-year PFS were 37.7% and 24.8%. Median time to polymetastatic disease was 11.3 months. Grade 1 and 2 toxicity occurred in 21 (14.7%) and 3 (2.1%) patients. The results from this large multi-center study confirm the efficacy and safety of SBRT in the management of adrenal gland metastases, as a valid alternative to other more invasive local approaches.
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