Craniospinal irradiation of medulloblastoma in the supine position

Šlampa, Pavel; Zitterbart, Karel; Dušek, Ladislav; Růžičková, Jana; Magnová, Olga; Čoupek, Petr; Hübnerova, Petra; Ondrová, Barbora; Syptakova, Blazena

doi:10.1016/s1507-1367(06)71071-9

Cited by 4 publications

(5 citation statements)

References 29 publications

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“…PD-L1 expression was assessed by flow cytometry 2, 4, 8, 24, and 48 hours later. 2 Gy was chosen as a starting dose since this approximates a typical daily fraction during standard of care radiation therapy for MB [ 31 ]. The percent change in PD-L1 expression above baseline for each cell line was analyzed at the various radiation doses and time points and compared concomitantly to PD-L1 expression induced by IFN-γ (Figure 6 ).…”

Section: Resultsmentioning

confidence: 99%

“…Although the greatest induction of PD-L1 occurred after exposure to 10 Gy radiation, similar trends were noted at 2 and 5 Gy. We could not fully simulate the typical 54 Gy given over 6 weeks used for newly diagnosed MB in an in vitro study; however, the changes noted at just 2 Gy could have implications for patients undergoing typical fractionated radiotherapy [ 31 ]. 10 Gy approximates a stereotactic radiation dose that might be used in the setting of focally relapsed MB and has been shown by our group to be an effective strategy in a mouse model of glioma [ 29 ].…”

Section: Discussionmentioning

confidence: 99%

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PD-L1 expression in medulloblastoma: an evaluation by subgroup

et al. 2018

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BackgroundThis study evaluated the expression of PD-L1 and markers of immune mediated resistance in human medulloblastoma (MB), the most common malignant pediatric brain tumor.ResultsOverall levels of PD-L1 in human MB were low; however, some cases demonstrated robust focal expression associated with increased immune infiltrates. The case with highest PD-L1 expression was a sonic hedgehog (SHH) MB. In cell lines, SHH MB, which are low-MYC expressing, demonstrated both constitutive and inducible expression of PD-L1 while those in Group 3/4 that expressed high levels of MYC had only inducible expression. In vitro, IFN-γ robustly stimulated the expression of PD-L1 in all cell lines while radiation induced variable expression. Forced high MYC expression did not significantly alter PD-L1.MethodsHuman MB tumor samples were evaluated for expression of PD-L1 and immune cell markers in relation to molecular subgroup assignment. PD-L1 expression was functionally analyzed under conditions of interferon gamma (IFN-γ), radiation, and MYC overexpression.ConclusionsMB expresses low levels of PD-L1 facilitating immune escape. Importantly, TH1 cytokine stimulation appears to be the most potent inducer of PD-L1 expression in vitro suggesting that an inflamed tumor microenvironment is necessary for PD-1 pathway activation in this tumor.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

PD-L1 expression in medulloblastoma: an evaluation by subgroup

et al. 2018

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“…This is the consequence of the length of the field which can be obtained with a conventional linear accelerator (40 cm). The change in set-up may result in underdosed areas and overdosed ones in regions where the fields overlap [45]. …”

Section: Discussionmentioning

confidence: 99%

Tomotherapy – a different way of dose delivery in radiotherapy

Piotrowski¹,

Skórska²,

Jodda³

et al. 2012

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Aim of the studyHelical tomotherapy is one of the methods of radiotherapy. This method enables treatment implementation for a wide spectrum of clinical cases. The vast array of therapeutic uses of helical tomotherapy results directly from the method of dose delivery, which is significantly different from the classic method developed for conventional linear accelerators. The paper discusses the method of dose delivery by a tomotherapy machine. Moreover, an analysis and presentation of treatment plans was performed in order to show the therapeutic possibilities of the applied technology. Dose distributions were obtained for anaplastic medulloblastoma, multifocal metastases to brain, vulva cancer, tongue cancer, metastases to bones, and advanced skin cancer. Tomotherapy treatment plans were compared with conventional linear accelerator plans.ResultsFollowing the comparative analysis of tomotherapy and conventional linear accelerator plans, in each case we obtained the increase in dose distribution conformity manifested in greater homogeneity of doses in the radiation target area for anaplastic medulloblastoma, multifocal metastases to brain, vulva cancer, metastases to bones, and advanced skin cancer, and the reduction of doses in organs at risk (OAR) for anaplastic medulloblastoma, vulva cancer, tongue cancer, and advanced skin cancer. The time of treatment delivery in the case of a tomotherapy machine is comparable to the implementation of the plan prepared in intensity-modulated radiotherapy (IMRT) technique for a conventional linear accelerator. In the case of tomotherapy the application of a fractional dose was carried out in each case during one working period of the machine. For a conventional linear accelerator the total value of the fractional dose in the case of anaplastic medulloblastoma and metastases to bones was delivered using several treatment plans, for which a change of set-up was necessary during a fraction.ConclusionThe obtained results confirm that tomotherapy offers the possibility to obtain precise treatment plans together with the simplification of the therapeutic system.

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“…While the original set-up for craniospinal irradiation [1] employed a prone patient position, there are numerous studies advocating the supine patient position [22][23][24][25]. After judging the advantages and the disadvantages of both set-ups, we decided to employ it as well.…”

Section: Prone Vs Supine Patient Positionmentioning

confidence: 99%