Clinical Results of Mean GTV Dose Optimized Robotic-Guided Stereotactic Body Radiation Therapy for Lung Tumors

Baumann, René; Chan, Mark K.H.; Pyschny, Florian; Stera, Susanne; Malzkuhn, Bettina; Wurster, Stefan; Huttenlocher, Stefan; Szücs, Marcella; Imhoff, Detlef; Keller, Christian; Balermpas, Panagiotis; Rades, Dirk; Rödel, Claus; Dunst, Jürgen; Hildebrandt, Guido; Blanck, Oliver

doi:10.3389/fonc.2018.00171

Cited by 28 publications

(24 citation statements)

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“…The synergistic effects of combined SRS and TT/IT are well described [8-11, 28, 29], although local response is often not presented in greater detail. Additionally, local control is often correlated to dose and lesion volume, but the authors did not see any dose or lesion and/or volume based response differences in their analysis, which might be explained by GTV mean dose optimization [24,30,31].…”

Section: Discussionmentioning

confidence: 92%

Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases

Wilhelm

Chan²,

Abel³

et al. 2020

Strahlenther Onkol

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Purpose For step-and-shoot robotic stereotactic radiosurgery (SRS) the dose delivered over time, called local tumor-dose-rate (TDR), may strongly vary during treatment of multiple lesions. The authors sought to evaluate technical parameters influencing TDR and correlate TDR to clinical outcome. Material and methods A total of 23 patients with 162 oligo (1–3) and multiple (>3) brain metastases (OBM/MBM) treated in 33 SRS sessions were retrospectively analyzed. Median PTV were 0.11 cc (0.01–6.36 cc) and 0.50 cc (0.12–3.68 cc) for OBM and MBM, respectively. Prescription dose ranged from 16 to 20 Gy prescribed to the median 70% isodose line. The maximum dose-rate for planning target volume (PTV) percentage p in time span s during treatment (TDRs,p) was calculated for various p and s based on treatment log files and in-house software. Results TDR60min,98% was 0.30 Gy/min (0.23–0.87 Gy/min) for OBM and 0.22 Gy/min (0.12–0.63 Gy/min) for MBM, respectively, and increased by 0.03 Gy/min per prescribed Gy. TDR60min,98% strongly correlated with treatment time (ρ = −0.717, p < 0.001), monitor units (MU) (ρ = −0.767, p < 0.001), number of beams (ρ = −0.755, p < 0.001) and beam directions (ρ = −0.685, p < 0.001) as well as lesions treated per collimator (ρ = −0.708, P < 0.001). Median overall survival (OS) was 20 months and 1‑ and 2‑year local control (LC) was 98.8% and 90.3%, respectively. LC did not correlate with any TDR, but tumor response (partial response [PR] or complete response [CR]) correlated with all TDR in univariate analysis (e.g., TDR60min,98%: hazard ration [HR] = 0.974, confidence interval [CI] = 0.952–0.996, p = 0.019). In multivariate analysis only concomitant targeted therapy or immunotherapy and breast cancer tumor histology remained a significant factor for tumor response. Local grade ≥2 radiation-induced tissue reactions were noted in 26.3% (OBM) and 5.2% (MBM), respectively, mainly influenced by tumor volume (p < 0.001). Conclusions Large TDR variations are noted during MBM-SRS which mainly arise from prolonged treatment times. Clinically, low TDR corresponded with decreased local tumor responses, although the main influencing factor was concomitant medication.

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Section: Discussionmentioning

confidence: 92%

Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases

Wilhelm

Chan²,

Abel³

et al. 2020

Strahlenther Onkol

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“…The GTV was manually outlined for clinical use on the planning CT, and the PTV was generated by adding a margin of 3-4 mm (Table 1 ). A set of volumetric and dosimetric parameters was extracted from the planning system including GTV (gross tumor volume), PTV (planning target volume), GTV-D max (maximal dose in GTV), GTV-D mean (mean dose in GTV), GTV-D 95% (dose achieved in 95% of the GTV), PTV-D 95% (dose achieved in 95% of the PTV) and lung doses Lung-D 1ml , Lung-D 10ml , Lung-D 50ml , Lung-D 100ml [ 13 , 37 – 40 ], see Table 1 . According to the different dose/ fractionation schemes, the doses covered a wide range in both datasets.…”

Section: Methodsmentioning

confidence: 99%

Radiomics for prediction of radiation-induced lung injury and oncologic outcome after robotic stereotactic body radiotherapy of lung cancer: results from two independent institutions

et al. 2021

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Objectives To generate and validate state-of-the-art radiomics models for prediction of radiation-induced lung injury and oncologic outcome in non-small cell lung cancer (NSCLC) patients treated with robotic stereotactic body radiation therapy (SBRT). Methods Radiomics models were generated from the planning CT images of 110 patients with primary, inoperable stage I/IIa NSCLC who were treated with robotic SBRT using a risk-adapted fractionation scheme at the University Hospital Cologne (training cohort). In total, 199 uncorrelated radiomic features fulfilling the standards of the Image Biomarker Standardization Initiative (IBSI) were extracted from the outlined gross tumor volume (GTV). Regularized models (Coxnet and Gradient Boost) for the development of local lung fibrosis (LF), local tumor control (LC), disease-free survival (DFS) and overall survival (OS) were built from either clinical/ dosimetric variables, radiomics features or a combination thereof and validated in a comparable cohort of 71 patients treated by robotic SBRT at the Radiosurgery Center in Northern Germany (test cohort). Results Oncologic outcome did not differ significantly between the two cohorts (OS at 36 months 56% vs. 43%, p = 0.065; median DFS 25 months vs. 23 months, p = 0.43; LC at 36 months 90% vs. 93%, p = 0.197). Local lung fibrosis developed in 33% vs. 35% of the patients (p = 0.75), all events were observed within 36 months. In the training cohort, radiomics models were able to predict OS, DFS and LC (concordance index 0.77–0.99, p < 0.005), but failed to generalize to the test cohort. In opposite, models for the development of lung fibrosis could be generated from both clinical/dosimetric factors and radiomic features or combinations thereof, which were both predictive in the training set (concordance index 0.71– 0.79, p < 0.005) and in the test set (concordance index 0.59–0.66, p < 0.05). The best performing model included 4 clinical/dosimetric variables (GTV-Dmean, PTV-D95%, Lung-D1ml, age) and 7 radiomic features (concordance index 0.66, p < 0.03). Conclusion Despite the obvious difficulties in generalizing predictive models for oncologic outcome and toxicity, this analysis shows that carefully designed radiomics models for prediction of local lung fibrosis after SBRT of early stage lung cancer perform well across different institutions.

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“…In a retrospective analysis of cases treated with Cyberknife, 33 irrespective of the tracking method, a mean GTV dose optimized treatment planning, allowing for lower PTV doses, and achieved substantially higher LC rates compared to those of studies that used a more homogeneous dose prescription. 34 Inhomogeneity could also prevent target dose miscalculation by different algorithms.…”

Section: What Dose Distribution Best Correlates With Lc and Os?mentioning

confidence: 99%

Dose prescription in SBRT for early-stage non-small cell lung cancer: are we all speaking the same language?

Merlotti

Bonomo

Ragona

et al. 2020

Tumori

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Introduction: Stereotactic body radiation therapy is increasingly used in the treatment of early-stage lung cancers. Guidelines provide indications regarding the constraints to the organs at risk (OARs) and the minimum coverage of the planning target volume but do not suggest optimal dose distribution. Data on dose distribution from the different published series are not comparable due to different prescription modalities and reported dose parameters. Methods: We conducted a review of the published data on dose prescription, focusing on the role of homogeneity on local tumor control, and present suggestions on how to specify and report the prescriptions to permit comparisons between studies or between cases from different centers. Conclusions: To identify the dose-prescription modality that better correlates with oncologic outcomes, future studies should guarantee a close uniformity of dose distribution between cases and complete dose parameters reporting for treatment volumes and OARs.

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Clinical Results of Mean GTV Dose Optimized Robotic-Guided Stereotactic Body Radiation Therapy for Lung Tumors

Cited by 28 publications

References 64 publications

Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases

Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases

Radiomics for prediction of radiation-induced lung injury and oncologic outcome after robotic stereotactic body radiotherapy of lung cancer: results from two independent institutions

Dose prescription in SBRT for early-stage non-small cell lung cancer: are we all speaking the same language?

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