Whole Brain Irradiation With Hippocampal Sparing and Dose Escalation on Multiple Brain Metastases: A Planning Study on Treatment Concepts

Prokic, V.; Wiedenmann, Nicole; Fels, Franziska; Schmucker, Marianne; Nieder, Carsten; Grosu, Anca‐Ligia

doi:10.1016/j.ijrobp.2012.02.036

Cited by 77 publications

(62 citation statements)

References 20 publications

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“…In their study, the hippocampus was conformally avoided with the mean normalized dose to about 6 Gy, and treatment times were reported from about 10 to 22 min. Similarly, Prokic and colleagues (24) developed a new treatment planning strategy in WBRT patients with hippocampal sparing with stereotactic SIB or sequential boost (SB) concepts. The VMAT plans were generated for 10 patients with up to eight brain tumors for 30 Gy in 12 fraction to the whole brain and 51 Gy in 12 fractions to individual brain tumors (in SIB) and 30 Gy in 12 fraction to the whole brain and 18 Gy in 2 fractions to brain metastases (in SB) with 5 mm and 10 mm HAZ.…”

Section: Discussionmentioning

confidence: 99%

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Pokhrel

Sood

Lominska

et al. 2015

J Applied Clin Med Phys

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The purpose of this study was to retrospectively investigate the accuracy, plan quality, and efficiency of using intensity‐modulated arc therapy (IMAT) for whole brain radiotherapy (WBRT) patients with sparing not only the hippocampus (following RTOG 0933 compliance criteria) but also other organs at risk (OARs). A total of 10 patients previously treated with nonconformal opposed laterals whole‐brain radiotherapy (NC‐WBRT) were retrospectively replanned for hippocampal sparing using IMAT treatment planning. The hippocampus was volumetrically contoured on fused diagnostic T1‐weighted MRI with planning CT images and hippocampus avoidance zone (HAZ) was generated using a 5 mm uniform margin around the hippocampus. Both hippocampi were defined as one paired organ. Whole brain tissue minus HAZ was defined as the whole‐brain planning target volume (WB‐PTV). Highly conformal IMAT plans were generated in the Eclipse treatment planning system for Novalis TX linear accelerator consisting of high‐definition multileaf collimators (HD‐MLCs: 2.5 mm leaf width at isocenter) and 6 MV beam for a prescription dose of 30 Gy in 10 fractions following RTOG 0933 dosimetric criteria. Two full coplanar arcs with orbits avoidance sectors were used. In addition to RTOG criteria, doses to other organs at risk (OARs), such as parotid glands, cochlea, external/middle ear canals, skin, scalp, optic pathways, brainstem, and eyes/lens, were also evaluated. Subsequently, dose delivery efficiency and accuracy of each IMAT plan was assessed by delivering quality assurance (QA) plans with a MapCHECK device, recording actual beam‐on time and measuring planed vs. measured dose agreement using a gamma index. On IMAT plans, following RTOG 0933 dosimetric criteria, the maximum dose to WB‐PTV, mean WB‐PTV D2%, and mean WB‐PTV D98% were 34.9±0.3 Gy,33.2±0.4 Gy, and 26.0±0.4 Gy, respectively. Accordingly, WB‐PTV received the prescription dose of 30 Gy and mean V30 was 90.5%±0.5%. The D100%, and mean and maximum doses to hippocampus were 8.4±0.3 Gy,11.2±0.3 Gy, and 15.6±0.4 Gy, on average, respectively. The mean values of homogeneity index (HI) and conformity index (CI) were 0.23×0.02 and 0.96×0.02, respectively. The maximum point dose to WB‐PTV was 35.3 Gy, well below the optic pathway tolerance of 37.5 Gy. In addition, compared to NC‐WBRT, dose reduction of mean and maximum of parotid glands from IMAT were 65% and 50%, respectively. Ear canals mean and maximum doses were reduced by 26% and 12%, and mean and maximum scalp doses were reduced by 9 Gy (32%) and 2 Gy (6%), on average, respectively. The mean dose to skin was 9.7 Gy with IMAT plans compared to 16 Gy with conventional NC‐WBRT, demonstrating that absolute reduction of skin dose by a factor of 2. The mean values of the total number of monitor units (MUs) and actual beam on time were 719×44 and 2.34×0.14 min, respectively. The accuracy of IMAT QA plan delivery was (98.1±0.8) %, on average, with a 3%/3 mm gamma index passing rate criteria. All of these plans were considered clinically acceptable per ...

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Section: Discussionmentioning

confidence: 99%

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Pokhrel

Sood

Lominska

et al. 2015

J Applied Clin Med Phys

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“…The dose of the steroids is another possible issue without clear recommendation however the dose should be driven by neurological symptoms also taking into account the side effects of long term steroid treatment. One of the possible technique how to avoid above mentioned unwanted side effect of WBRT is to perform HA-WBRT avoidance (35,38). Considering radiotherapy of hippocampal structures is considered to be responsible for cognitive impairment its avoidance could possibly preserve the cognitive functions.…”

Section: Discussionmentioning

confidence: 99%

Treatment of brain metastases of renal cell cancer with combined hypofractionated stereotactic radiotherapy and whole brain radiotherapy with hippocampal sparing

et al. 2016

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Abstract.Renal cell cancer patients with brain metastatic disease generally have poor prognosis. Treatment options include surgery, radiotherapy, targeted therapy or best supportive care with respect to disease burden, patient preference and performance status. In the present case report the radiotherapy technique combining whole brain radiotherapy with hippocampal sparing (hippocampal avoidance whole brain radiotherapy HA-WBRT) and hypofractionated stereotactic radiotherapy (SRT) of the brain metastases is performed in a patient with metastatic renal cell carcinoma. HA-WBRT was administered to 30 Gy in 10 fractions with sparing of the hippocampal structures and SRT of 21 Gy in 3 fractions to brain metastases which has preceded the HA-WBRT. Two single arc volumetric modulated arc radiotherapy (VMAT) plans were prepared using Monaco planning software. The HA-WBRT treatment plan achieved the following results: D2=33.91 Gy, D98=25.20 Gy, D100=14.18 Gy, D50=31.26 Gy. The homogeneity index was calculated as a deduction of the minimum dose in 2% and 98% of the planning target volume (PTV), divided by the minimum dose in 50% of the PTV. The maximum dose to the hippocampus was 17.50 Gy and mean dose was 11.59 Gy. The following doses to organs at risk (OAR) were achieved: Right opticus Dmax, 31.96 Gy; left opticus Dmax, 30.96 Gy; chiasma D max, 32,76 Gy. The volume of PTV for stereotactic radiotherapy was 3,736 cm 3 , with coverage D100=20.95 Gy and with only 0.11% of the PTV being irradiated to dose below the prescribed dose. HA-WBRT with SRT represents a feasible technique for radiotherapy of brain metastatic disease, however this technique is considerably demanding on departmental equipment and staff time/experience. IntroductionRenal cell cancer (RCC) with brain metastases is a disease with poor prognosis (1). The treatment strategy generally depends on the patient performance status, tumor burden and patient preference. The departmental facility device equipment often plays a significant role in the decision making process. Targeted therapy is the mainstay of the systemic treatment at present (2). There are a few viable treatment options with respect to the number of brain lesions, their location and patient overall fitness: Surgical resection, hypofractionated stereotactic radiotherapy (SRT), stereotactic radiosurgery (SRS), whole brain radiotherapy (WBRT) and symptomatic treatment with steroids (best supportive care (BSC) (3). The main difference between SRS and SRT is in the number of fractions delivered. SRS utilizes only 1 fraction (1 day) for delivery of the whole ablative dose of radiotherapy, which imitates the surgical techniques of treating a patient in one day; whereas, SRT uses 3-6 fractions for treatment dose delivery (4,5). Several prognostic indexes were created to assess the expected patient survival to help clinicians to decide about proper treatment strategy. The recursive partitioning analysis (RPA) index combines the patient's performance status, age and disease burden. One of the greatest disadv...

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“…The SIB together with this hypofractionated schedule in WBRT (20 Gy in five fractions) (40 Gy in five fractions) has proven to be feasible. This schedule offers the advantage of shorter treatment time, which could be very useful in oligometastatic patients that need systemic therapy (Figure 9) [38][39][40][41][42][43]. …”

Section: Radiotherapymentioning

confidence: 99%

Radiation Therapy with a Simultaneous Integrated Boost

Katsochi¹

2017

Radiotherapy

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Radiotherapy has an established role in the treatment of cancer and represents a definitive, less invasive approach for various cancer types. Its main aim is to deliver the maximum dose to the tumor with minimal toxicity on neighboring healthy tissues. Therefore, the precise determination of the target and its spatial relation to critical surrounding organs is of main importance. New imaging modalities such as the CT, MRI, and PET/CT offer more anatomical detail and facilitate the accurate delineation of the target volume and the organs at risk. The recent advances in 3D-CRT and IMRT radiation techniques offer high accuracy in tumor targeting and ensure safe dose escalation. Moreover, the introduction of IGRT offers the opportunity to safely apply a supplementary dose to the macroscopic tumor. In trials conducted, a simultaneous integrated boost (SIB) has proved to be feasible in various cancer localizations, to safely increase the total delivered dose, shorten the total treatment time and results in increased tumor control while keeping the side effects low at the same time. However, more trials need to be conducted to establish an acceptable protocol.

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Whole Brain Irradiation With Hippocampal Sparing and Dose Escalation on Multiple Brain Metastases: A Planning Study on Treatment Concepts

Cited by 77 publications

References 20 publications

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Potential for reduced radiation‐induced toxicity using intensity‐modulated arc therapy for whole‐brain radiotherapy with hippocampal sparing

Treatment of brain metastases of renal cell cancer with combined hypofractionated stereotactic radiotherapy and whole brain radiotherapy with hippocampal sparing

Radiation Therapy with a Simultaneous Integrated Boost

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