Pulsed Reduced Dose-rate Radiotherapy as Re-irradiation for Brain Metastasis in a Patient with Lung Squamous-celled Carcinoma

Li, Guanghui; Liu, Yong; Tang, Jinliang; Zhang, Dong; Zhou, Pu; Yang, Dezhong; Ma, Chuan-Kun

doi:10.1093/jjco/hys091

Cited by 9 publications

(5 citation statements)

References 12 publications

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“…In our institution, this technique has mainly been utilized to treat recurrent patients with life-threatening symptoms (obstruction of the airways, severe diarrhea, tumor bleeding, etc). Similar to those published works (Cannon et al 2007, Li et al 2012a, 2012b, Richards et al 2009 done with conventional radiotherapy, the patients treated in our institution tolerated the re-irradiation fairly well and the treatment outcome was clinically favorable. The two treatment techniques together with advanced image-guidance as investigated in this work are capable of delivering conformal dose distributions to the targets accurately, sparing nearby critical structures effectively for PLDR treatments, which further allowed escalated target doses to effectively relieve the symptoms and to retain quality of life for recurrent patients.…”

Section: Discussionsupporting

confidence: 83%

“…Therefore, this technique potentially improves the therapeutic ratio by introducing a more efficient cell killing to the tumor and an increased repair to the normal tissue. Its favorable clinical treatment outcomes have been reported for the treatments of recurrent glioblastoma (Cannon et al 2007), recurrent breast cancer (Richards et al 2009), metastatic brain tumors (Li et al 2012a), and recurrent nasopharyngeal cancer (Li et al 2012b).…”

Section: Introductionmentioning

confidence: 99%

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Investigation of pulsed IMRT and VMAT for re-irradiation treatments: dosimetric and delivery feasibilities

Lin

Price

et al. 2013

Phys. Med. Biol.

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Many tumor cells demonstrate hyperradiosensitivity at doses below ~50 cGy. Together with the increased normal tissue repair under low dose rate, the pulsed low dose rate radiotherapy (PLDR), which separates a daily fractional dose of 200 cGy into 10 pulses with 3 min interval between pulses (~20 cGy/pulse and effective dose rate 6.7 cGy min−1), potentially reduces late normal tissue toxicity while still providing significant tumor control for re-irradiation treatments. This work investigates the dosimetric and technical feasibilities of intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)-based PLDR treatments using Varian Linacs. Twenty one cases (12 real re-irradiation cases) including treatment sites of pancreas, prostate, pelvis, lung, head-and-neck, and breast were recruited for this study. The lowest machine operation dose rate (100 MU min−1) was employed in the plan delivery. Ten-field step-and-shoot IMRT and dual-arc VMAT plans were generated using the Eclipse TPS with routine planning strategies. The dual-arc plans were delivered five times to achieve a 200 cGy daily dose (~20 cGy arc−1). The resulting plan quality was evaluated according to the heterogeneity and conformity indexes (HI and CI) of the planning target volume (PTV). The dosimetric feasibility of retaining the hyperradiosensitivity for PLDR was assessed based on the minimum and maximum dose in the target volume from each pulse. The delivery accuracy of VMAT and IMRT at the 100 MU min−1 machine operation dose rate was verified using a 2D diode array and ion chamber measurements. The delivery reproducibility was further investigated by analyzing the Dynalog files of repeated deliveries. A comparable plan quality was achieved by the IMRT (CI 1.10–1.38; HI 1.04–1.10) and the VMAT (CI 1.08–1.26; HI 1.05–1.10) techniques. The minimum/maximum PTV dose per pulse is 7.9 ± 5.1 cGy/33.7 ± 6.9 cGy for the IMRT and 12.3 ± 4.1 cGy/29.2 ± 4.7 cGy for the VMAT. Six out of the 186 IMRT pulses (fields) were found to exceed 50 cGy maximum PTV dose per pulse while the maximum PTV dose per pulse was within 40 cGy for all the VMAT pulses (arcs). However, for VMAT plans, the dosimetric quality of the entire treatment plan was less superior for the breast cases and large irregular targets. The gamma passing rates for both techniques at the 100 MU min−1 dose rate were at least 94.1% (3%/3 mm) and the point dose measurements agreed with the planned values to within 2.2%. The average root mean square error of the leaf position was 0.93 ± 0.83 mm for IMRT and 0.53 ± 0.48 mm for VMAT based on the Dynalog file analysis. The RMS error of the leaf position was nearly identical for the repeated deliveries of the same plans. In general, both techniques are feasible for PLDR treatments. VMAT was more advantageous for PLDR with more uniform target dose per pulse, especially for centrally located tumors. However, for large, irregular and/or peripheral tumors, IMRT could produce more favorable PLDR plans. By taking the biological benefit of PLDR de...

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Section: Discussionsupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Investigation of pulsed IMRT and VMAT for re-irradiation treatments: dosimetric and delivery feasibilities

Lin

Price

et al. 2013

Phys. Med. Biol.

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“… 12 , 13 Several clinical studies have been reported using PLDR technique as reirradiation treatment for metastatic brain tumors and recurrence of breast cancer, glioblastoma, and nasopharyngeal carcinoma. 14 - 18 However, most clinical reports using PLDR treatment are case reports. It is also controversial whether PLDR can provide a therapeutic advantage in RT in vivo in the animal.…”

Section: Introductionmentioning

confidence: 99%

Local Tumor Control and Normal Tissue Toxicity of Pulsed Low-Dose Rate Radiotherapy for Recurrent Lung Cancer

et al. 2015

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Objectives:This study investigates (1) local tumor control and (2) normal tissue toxicity of pulsed low-dose rate radiotherapy (PLDR) for recurrent lung cancer.Methods:For study 1, nude mice were implanted with A549 tumors and divided into the following 3 groups: (1) control (n = 10), (2) conventional radiotherapy (RT; n = 10), and (3) PLDR (n = 10). Tumor-bearing mice received 2 Gy daily dose for 2 consecutive days. Weekly magnetic resonance imaging was used for tumor growth monitoring. For study 2, 20 mice received 8 Gy total body irradiation either continuously (n = 10) or 40 × 0.2 Gy pulses with 3-minute intervals (n = 10).Results:For study 1, both conventional RT and PLDR significantly inhibited the growth of A549 xenografts compared with the control group (>35% difference in the mean tumor volume; P < .05). The PLDR results were slightly better than conventional RT (8% difference in the mean tumor volume; P > .05). For study 2, the average weight was 20.94 ± 1.68 g and 25.69 ± 1.27 g and the survival time was 8 days and 12 days for mice treated with conventional RT and PLDR (P < .05), respectively.Conclusion:This study showed that PLDR could control A549 tumors as effectively as conventional RT, and PLDR induced much less normal tissue toxicity than conventional RT. Thus, PLDR would be a good modality for recurrent lung cancers.Advances in Knowledge:This article reports our results of an in vivo animal investigation of PLDR for the treatment of recurrent cancers, which may not be eligible for treatment because of the dose limitations on nearby healthy organs that have been irradiated in previous treatments. This was the first in vivo study to quantify the tumor control and normal tissue toxicities of PLDR using mice with implanted tumors, and our findings provided evidence to support the clinical trials that employ PLDR treatment techniques.

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“…More detailed discussions on PLDR clinical applications can be found in a recent review by Chen (2021). There have been several case reports on PLDR re-irradiation for recurrent GBM, head and neck cancer and brain metastases (Cannon et al 2007, Li et al 2012a, 2012b.…”

Section: Clinical Applicationsmentioning

confidence: 99%

Pulsed low dose-rate radiotherapy: radiobiology and dosimetry

Charlie¹

2022

Phys. Med. Biol.

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Pulsed low dose-rate radiotherapy (PLDR) relies on two radiobiological findings, the hyper-radiosensitivity of tumor cells at small doses and the reduced normal tissue toxicity at low dose rates. This is achieved by delivering the daily radiation dose of 2 Gy in 10 sub-fractions (pulses) with a 3-minute time interval, resulting in an effective low dose rate of 0.067 Gy/minute. In vitro cell studies and in vivo animal experiments demonstrated the therapeutic potential of PLDR treatments and provided useful preclinical data. Various treatment optimization strategies and delivery techniques have been developed for PLDR on existing linear accelerators. Preliminary results from early clinical studies have shown favorable outcomes for various treatment sites especially for recurrent cancers. This paper reviews the experimental findings of PLDR and dosimetric requirements for PLDR treatment planning and delivery, and summarizes major clinical studies on PLDR cancer treatments.

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Pulsed Reduced Dose-rate Radiotherapy as Re-irradiation for Brain Metastasis in a Patient with Lung Squamous-celled Carcinoma

Cited by 9 publications

References 12 publications

Investigation of pulsed IMRT and VMAT for re-irradiation treatments: dosimetric and delivery feasibilities

Investigation of pulsed IMRT and VMAT for re-irradiation treatments: dosimetric and delivery feasibilities

Local Tumor Control and Normal Tissue Toxicity of Pulsed Low-Dose Rate Radiotherapy for Recurrent Lung Cancer

Pulsed low dose-rate radiotherapy: radiobiology and dosimetry

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