Intensity-Modulated Radiotherapy–Based Stereotactic Body Radiotherapy for Medically Inoperable Early-Stage Lung Cancer: Excellent Local Control

Videtic, Gregory M.M.; Stephans, Kevin L.; Reddy, Chandana A.; Gajdos, S; Kolar, M.; Clouser, Edward; Djemil, T.

doi:10.1016/j.ijrobp.2009.05.004

Cited by 116 publications

(67 citation statements)

References 28 publications

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“…Numerous clinical reports have demonstrated excellent local control of the primary tumor with minimal normal tissue toxicity 1 , 2 , 3 , 4 , 5 . An accurate correlation between the computed dose and local tumor control achieved by SBRT is clinically important.…”

Section: Introductionmentioning

confidence: 99%

Dose differences in intensity‐modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT

Liu

Zhuang

Stephans

et al. 2015

J Applied Clin Med Phys

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For patients with medically inoperable early‐stage non‐small cell lung cancer (NSCLC) treated with stereotactic body radiation therapy, early treatment plans were based on a simpler dose calculation algorithm, the pencil beam (PB) calculation. Because these patients had the longest treatment follow‐up, identifying dose differences between the PB calculated dose and Monte Carlo calculated dose is clinically important for understanding of treatment outcomes. Previous studies found significant dose differences between the PB dose calculation and more accurate dose calculation algorithms, such as convolution‐based or Monte Carlo (MC), mostly for three‐dimensional conformal radiotherapy (3D CRT) plans. The aim of this study is to investigate whether these observed dose differences also exist for intensity‐modulated radiotherapy (IMRT) plans for both centrally and peripherally located tumors. Seventy patients (35 central and 35 peripheral) were retrospectively selected for this study. The clinical IMRT plans that were initially calculated with the PB algorithm were recalculated with the MC algorithm. Among these paired plans, dosimetric parameters were compared for the targets and critical organs. When compared to MC calculation, PB calculation overestimated doses to the planning target volumes (PTVs) of central and peripheral tumors with different magnitudes. The doses to 95% of the central and peripheral PTVs were overestimated by 9.7%±5.6% and 12.0%±7.3%, respectively. This dose overestimation did not affect doses to the critical organs, such as the spinal cord and lung. In conclusion, for NSCLC treated with IMRT, dose differences between the PB and MC calculations were different from that of 3D CRT. No significant dose differences in critical organs were observed between the two calculations.PACS number: 87.53.Ly

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Section: Introductionmentioning

confidence: 99%

Dose differences in intensity‐modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT

Liu

Zhuang

Stephans

et al. 2015

J Applied Clin Med Phys

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“…Clinical trials have demonstrated efficacy of this treatment modality with excellent local control rate and tolerable normal tissue toxicity. ( 1 – 5 ) …”

Section: Introductionmentioning

confidence: 99%

Dose calculation differences between Monte Carlo and pencil beam depend on the tumor locations and volumes for lung stereotactic body radiation therapy

Zhuang

Djemil

Pan

et al. 2013

J Applied Clin Med Phys

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Stereotactic body radiation therapy (SBRT) has been increasingly used as an efficacious treatment modality for early‐stage non‐small cell lung cancer. The accuracy of dose calculations is compromised due to the presence of inhomogeneity. For the purpose of a consistent prescription, radiation doses were calculated without heterogeneity correction in several RTOG trials. For patients participating in these trials, recalculations of the planned doses with more accurate dose methods could provide better correlations between the treatment outcomes and the planned doses. Using a Monte Carlo (MC) dose calculation algorithm as a gold standard, we compared the recalculated doses with the MC algorithm to the original pencil beam (PB) calculations for our institutional clinical lung SBRT plans. The focus of this comparison is to investigate the volume and location dependence on the differences between the two dose calculations. Thirty‐one clinical plans that followed RTOG and other protocol guidelines were retrospectively investigated in this study. Dosimetric parameters, such as D1, D95, and D99 for the PTV and D1 for organs at risk, were compared between two calculations. Correlations of mean lung dose and V20 of lungs between two calculations were investigated. Significant dependence on tumor size and location was observed from the comparisons between the two dose calculation methods. When comparing the PB calculations without heterogeneity correction to the MC calculations with heterogeneity correction, we found that in terms of D95 of PTV: (1) the two calculations resulted in similar D95 for edge tumors with volumes greater than 25.1 cc; (2) an average overestimation of 5% in PB calculations for edge tumors with volumes less than 25.1 cc; and (3) an average overestimation of 9% or underestimation of 3% in PB calculations for island tumors with volumes smaller or greater than 22.6 cc, respectively. With heterogeneity correction, the PB calculations resulted in an average reduction of 23.8% and 15.3% in the D95 for the PTV for island and edge lesions, respectively, when compared to the MC calculations. For organs at risks, very small differences were found among all the comparisons. Excellent correlations for mean dose and V20 of lungs were observed between the two calculations. This study demonstrated that using a single scaling factor may be overly simplified when accounting for the effects of heterogeneity correction. Accurate dose calculations, such as the Monte Carlo algorithms, are highly recommended to understand dose responses in lung SBRT.PACS number: 87.53.Ly

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“…This improves the local tumor control rates to higher than 90% at 3 years [86] and 73% at 5 years for stage I NSCLC, comparable to the rates after surgery [87]. Good quality of life, overall survival rate and low toxicity were also reported in addition to excellent local control [88,89]. Caution should be used when using SBRT to treat lung cancers near the central airways due to excessive toxicity [38].…”

Section: Treatment Improvementmentioning

confidence: 99%

Motion Management in Stereotactic Body Radiotherapy

Zhang

Yu²,

Stevens³

et al. 2013

J Nucl Med Radiat Ther

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With the technologic advancements in image guidance and dose delivery, stereotactic body radiotherapy (SBRT) is being widely used for cancer treatment in various anatomical locations as a noninvasive alternative to surgery. To deliver ablative doses to tumors with limited normal tissue toxicity, SBRT requires high accuracy in treatment setup which requires taking tumor motion into account. Techniques are also applied in SBRT to minimize tumor motion during dose delivery. This paper reviews techniques for motion management in SBRT.

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Intensity-Modulated Radiotherapy–Based Stereotactic Body Radiotherapy for Medically Inoperable Early-Stage Lung Cancer: Excellent Local Control

Cited by 116 publications

References 28 publications

Dose differences in intensity‐modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT

Dose differences in intensity‐modulated radiotherapy plans calculated with pencil beam and Monte Carlo for lung SBRT

Dose calculation differences between Monte Carlo and pencil beam depend on the tumor locations and volumes for lung stereotactic body radiation therapy

Motion Management in Stereotactic Body Radiotherapy

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