Dose Gradient Near Target–Normal Structure Interface for Nonisocentric CyberKnife and Isocentric Intensity-Modulated Body Radiotherapy for Prostate Cancer

Hossain, Sabbir; Xia, Peng; Huang, Kim; Descovich, M.; Chuang, Cynthia; Gottschalk, Alexander; Roach, Mack; Ma, Lijun

doi:10.1016/j.ijrobp.2009.07.1752

Cited by 42 publications

(36 citation statements)

References 21 publications

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“…This is a distinct advantage as rectal morbidity is one of the limiting factors in delivering hypofractionated radiotherapy. Our results are in accordance with a similar study done by Sabbir Hosaain, et al and Ceylan, et al [12][13] comparing these two modalities (CyberKnife and IMRT). However, in a study done by Shiu, et al comparing CyberKnife and IMRT dose distributions, they found the dose to critical organs were less in the IMRT plans [14].…”

Section: Conformation Number (Cn) Is Defined Assupporting

confidence: 93%

Dosimetric comparison of Stereotactic body radiotherapy and Intensity modulated radiotherapy to deliver hypofractionated radiotherapy in organ confined prostate cancer

Potharaju¹,

Murali²,

Gopalakrishna³

2013

Cureus

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We compared the dose conformity, homogeneity, dose to organs at risk, and remaining volume at risk of two radiotherapy techniques --stereotactic body radiotherapy and intensitymodulated radiotherapy (IMRT) to deliver hypofractionated radiotherapy in organ-confined prostate cancer. Eleven successive patients treated on the CyberKnife stereotactic robotic radiosurgical system were taken up for this study. The CT images, including the structures contoured, were imported through DICOM RT from the Multiplan (Accuray Inc., Sunnyvale, CA, USA) treatment planning system to the Plato Sunrise treatment planning system (Nucletron, The Netherlands) for creating IMRT treatment plans on the Linac. Treatment planning was done for five fractions, each fraction prescribed to a dose of 7.25 Gy to the planning target volume. Dose volume histograms were generated for the CyberKnife and Linac treatments for comparison. As per our protocol, a plan was considered adequate if at least 95% of planning target volume received the prescribed dose and satisfied the following constraints: a) volume of the rectum receiving 36Gy (V36) to < 1cc and b) volume of the bladder receiving 37Gy (V37) to < 10cc. Both the treatment techniques plans resulted in adequate planning target volume coverage (p value for D95, D90, D5, and V100% was 0.402, 0.97, 0.013, and 0.012, respectively). CyberKnife plans were more conformal (p value 0.001). Remaining volume at risk dose was significantly less in all CyberKnife plans at [V100% (p=0.01), V95% (p=.004), V90% (p=.001), V80% (p=0.02), V70 (p=0.03), V40% (p=0.021), and V30% (p=0.001)] dose levels. The mean dose to rectum was lower in the CyberKnife plans (The p value for V100%, V80%, V50% and V30% dose levels was 0.02, 0.0001, 0.0002, and 0.12, respectively).

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Section: Conformation Number (Cn) Is Defined Assupporting

confidence: 93%

Dosimetric comparison of Stereotactic body radiotherapy and Intensity modulated radiotherapy to deliver hypofractionated radiotherapy in organ confined prostate cancer

Potharaju¹,

Murali²,

Gopalakrishna³

2013

Cureus

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“…It may cause problems where patients with similar OVHs but very different target sizes may differ significantly in their organ doses due to more rapid dose fall-off outside small targets [18]. This study addressed this issue by refining the approach with the addition of the target volume factor.…”

Section: Methodsmentioning

confidence: 99%

Improved robotic stereotactic body radiation therapy plan quality and planning efficacy for organ-confined prostate cancer utilizing overlap-volume histogram-driven planning methodology

Pang

Lei

et al. 2014

Radiotherapy and Oncology

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“…Studies investigating a high dose-rate (HDR) brachytherapy boost delivering 4–11.5 Gy/fraction over 2 to 4 sessions combined with EBRT report five-year biochemical control rates in excess of 85% for intermediate-risk prostate cancer patients with acceptable toxicities [4]. The tight margins and steep dose gradients delivered with HDR brachytherapy can be approximated with SBRT using the CyberKnife (CK) system, [5,6] which uses real-time image guidance to account for intrafraction prostatic motion [7]. EBRT with an SBRT boost has been explored in intermediate-risk prostate cancer with favorable early results [8,9].…”

Section: Introductionmentioning

confidence: 99%

Hypofractionated stereotactic body radiation therapy as monotherapy for intermediate-risk prostate cancer

Ju¹,

Wang

Oermann³

et al. 2013

Radiat Oncol

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BackgroundHypofractionated stereotactic body radiation therapy (SBRT) has been advanced as monotherapy for low-risk prostate cancer. We examined the dose distributions and early clinical outcomes using this modality for the treatment of intermediate-risk prostate cancer.MethodsForty-one sequential hormone-naïve intermediate-risk prostate cancer patients received 35–36.25 Gy of CyberKnife-delivered SBRT in 5 fractions. Radiation dose distributions were analyzed for coverage of potential microscopic ECE by measuring the distance from the prostatic capsule to the 33 Gy isodose line. PSA levels, toxicities, and quality of life (QOL) measures were assessed at baseline and follow-up.ResultsAll patients completed treatment with a mean coverage by the 33 Gy isodose line extending >5 mm beyond the prostatic capsule in all directions except posteriorly. Clinical responses were documented by a mean PSA decrease from 7.67 ng/mL pretreatment to 0.64 ng/mL at the median follow-up of 21 months. Forty patients remain free from biochemical progression. No Grade 3 or 4 toxicities were observed. Mean EPIC urinary irritation/obstruction and bowel QOL scores exhibited a transient decline post-treatment with a subsequent return to baseline. No significant change in sexual QOL was observed.ConclusionsIn this intermediate-risk patient population, an adequate radiation dose was delivered to areas of expected microscopic ECE in the majority of patients. Although prospective studies are needed to confirm long-term tumor control and toxicity, the short-term PSA response, biochemical relapse-free survival rate, and QOL in this interim analysis are comparable to results reported for prostate brachytherapy or external beam radiotherapy.Trial registrationThe Georgetown Institutional Review Board has approved this retrospective study (IRB 2009–510).

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Dose Gradient Near Target–Normal Structure Interface for Nonisocentric CyberKnife and Isocentric Intensity-Modulated Body Radiotherapy for Prostate Cancer

Cited by 42 publications

References 21 publications

Dosimetric comparison of Stereotactic body radiotherapy and Intensity modulated radiotherapy to deliver hypofractionated radiotherapy in organ confined prostate cancer

Dosimetric comparison of Stereotactic body radiotherapy and Intensity modulated radiotherapy to deliver hypofractionated radiotherapy in organ confined prostate cancer

Improved robotic stereotactic body radiation therapy plan quality and planning efficacy for organ-confined prostate cancer utilizing overlap-volume histogram-driven planning methodology

Hypofractionated stereotactic body radiation therapy as monotherapy for intermediate-risk prostate cancer

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