Second Cancer Risk after simultaneous integrated boost radiation therapy of right sided breast cancer with and without flattening filter

Dobler, Barbara; Maier, Johannes; Knott, Bernadette; Maerz, Manuel; Loeschel, Rainer; Koelbl, Oliver

doi:10.1007/s00066-016-1025-5

Cited by 20 publications

(18 citation statements)

References 24 publications

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“…The only advantage of FFF mode observed in our study was the reduction in peripheral dose corresponding to a decreased risk of radiation induced second cancers in peripheral organs as it also has been observed for the treatment of breast cancer in a previous study [43]. This, however, is of interest only for a therapy with curative intent, as it is the case e.g.…”

Section: Discussionsupporting

confidence: 62%

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

et al. 2017

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BackgroundThe aim of this study was to investigate if the flattening filter free (FFF) irradiation mode of a linear accelerator (linac) is advantageous as compared to the flat beam (FF) irradiation mode in intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for carcinoma of the hypopharynx / larynx.MethodsFour treatment plans were created for each of 10 patients for an Elekta Synergy linac with Agility collimating device, a dual arc VMAT and a nine field step and shoot IMRT each with and without flattening filter. Plan quality was compared considering target coverage and dose to the organs at risk. All plans were verified by a 2D–ionization-chamber-array and delivery times were compared. Peripheral point doses were determined as a measure of second cancer risk. The Wilcoxon test was used for statistical analysis with a significance level of 0.05.ResultsPlan quality was similar for all four treatment plans without statistically significant differences of clinical relevance. The clinical goals were met in all plans for the PTV-SIB (V95% > 95%), the spinal cord (D1ccm < 45 Gy) and the brain stem (D1ccm < 48 Gy). For the parotids, the goal of D50% < 30 Gy was met in 70% and 60% of the plans for the left and right parotid respectively, and the V95% of the SIB reached an average of 94%. Delivery times were similar for FF and FFF and significantly decreased by around 70% for VMAT as compared to IMRT. Peripheral doses were significantly reduced by 18% in FFF mode as compared to FF and by 26% for VMAT as compared to IMRT. Lowest peripheral doses were found for VMAT FFF, followed by VMAT FF.ConclusionsThe FFF mode of a linear accelerator is advantageous for the treatment of hypopharynx/larynx carcinoma only with respect to reduction of second cancer induction in peripheral organs for the combination of Elekta Synergy linacs and Oncentra® External Beam v4.5 treatment planning system. This might be of interest in a therapy with curative intent.

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Section: Discussionsupporting

confidence: 62%

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

et al. 2017

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“…A reduction of the treatment time would represent an additional advantage, especially in the treatment of pediatric patients. The flattening filter produces scatter radiation; therefore, its removal has the positive effect of reducing the out‐of‐field dose,10 which may lead to reduced second cancer risk as it has been shown for the treatment of breast cancer in a previous study 11. To our knowledge, no reports about second cancer risk have been published for ependymoma.…”

Section: Introductionmentioning

confidence: 87%

Second cancer risk after radiation therapy of ependymoma using the flattening filter free irradiation mode of a linear accelerator

Moret

Obermeier

Pohl

et al. 2018

J Applied Clin Med Phys

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Pediatric patients suffering from ependymoma are usually treated with cranial or craniospinal three‐dimensional (3D) conformal radiotherapy (3DCRT). Intensity‐modulated techniques spare dose to the surrounding tissue, but the risk for second malignancies may be increased due to the increase in low‐dose volume. The aim of this study is to investigate if the flattening filter free (FFF) mode allows reducing the risk for second malignancies compared to the mode with flattening filter (FF) for intensity‐modulated techniques and to 3DCRT. A reduction of the risk would be advantageous for treating pediatric ependymoma. 3DCRT was compared to intensity‐modulated radiation therapy (IMRT) and volumetric‐modulated arc therapy (VMAT) with and without flattening filter. Dose–volume histograms (DVHs) were compared to evaluate the plan quality and used to calculate the excess absolute risk (EAR) to develop second cancer in the brain. Dose verification was performed with a two‐dimensional (2D) ionization chamber array and the out‐of‐field dose was measured with an ionization chamber to determine the EAR in peripheral organs. Delivery times were measured. Both VMAT and IMRT achieved similar plan quality in terms of dose sparing in the OAR and higher PTV coverage as compared to 3DCRT. Peripheral dose in low‐dose region, which is proportional to the EAR in organs located in this region, for example, gonads, bladder, or bowel, could be significantly reduced using FFF. The lowest peripheral EAR and lowest delivery times were hereby achieved with VMATFFF. The EAR calculated based on DVH in the brain could not be reduced using FFF mode. VMATFFF improved the target coverage and homogeneity and kept the dose in the OAR similar compared to 3DCRT. In addition, delivery times were significantly reduced using VMATFFF. Therefore, for radiotherapy of ependymoma patients, VMATFFF may be considered advantageous for the combination of Elekta Synergy linac and Oncentra External Beam planning system used in this study.

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“…The flatness filter has been described as the main source of photon scatter in the treatment head [11]. Additional peripheral dose resulting from this contribution has been confirmed in some publications referring to other entities [12][13][14][15][16][17][18] and increases the risk for secondary malignancies. Pituitary adenomas represent about 10% of all intracranial tumors [19].…”

Section: Introductionmentioning

confidence: 86%

The influence of radiotherapy techniques on the plan quality and on the risk of secondary tumors in patients with pituitary adenoma

Treutwein¹,

Steger²,

Loeschel

et al. 2020

BMC Cancer

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Background: This planning study compares different radiotherapy techniques for patients with pituitary adenoma, including flatness filter free mode (FFF), concerning plan quality and secondary malignancies for potentially young patients. The flatness filter has been described as main source of photon scatter.Material and methods: Eleven patients with pituitary adenoma were included. An Elekta Synergy™ linac was used in the treatment planning system Oncentra® and for the measurements. 3D plans, IMRT, and VMAT plans and noncoplanar varieties were considered. The plan quality was evaluated regarding homogeneity, conformity, delivery time and dose to the organs at risk. The secondary malignancy risk was calculated from dose volume data and from measured dose to the periphery using different models for carcinoma and sarcoma risk.Results: The homogeneity and conformity were nearly unchanged with and without flattening filter, neither was the delivery time found substantively different. VMAT plans were more homogenous, conformal and faster in delivery than IMRT plans. The secondary cancer risk was reduced with FFF both in the treated region and in the periphery. VMAT plans resulted in a higher secondary brain cancer risk than IMRT plans, but the risk for secondary peripheral cancer was reduced. Secondary sarcoma risk plays a minor role. No advantage was found for non-coplanar techniques. The FFF delivery times were not shortened due to additional monitor units needed and technical limitations. The risk for secondary brain cancer seems to depend on the irradiated volume. Secondary sarcoma risk is much smaller than carcinoma risk in accordance to the results of the atomic bomb survivors. The reduction of the peripheral dose and resulting secondary malignancy risk for FFF is statistically significant. However, it is negligible in comparison to the risk in the treated region.Conclusion: Treatments with FFF can reduce secondary malignancy risk while retaining similar quality as with flattening filter and should be preferred. VMAT plans show the best plan quality combined with lowest peripheral secondary malignancy risk, but highest level of second brain cancer risk. Taking this into account VMAT FFF seems the most advantageous technique for the treatment of pituitary adenomas with the given equipment.

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Second Cancer Risk after simultaneous integrated boost radiation therapy of right sided breast cancer with and without flattening filter

Abstract: The use of FFF mode allows reducing the EAR significantly when tVMAT is used as the treatment technique. When second cancer risk is a major concern, tVMAT FFF is considered the preferred treatment option in SIB irradiation of right-sided breast cancer.

Cited by 20 publications

References 24 publications

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

Second cancer risk after radiation therapy of ependymoma using the flattening filter free irradiation mode of a linear accelerator

The influence of radiotherapy techniques on the plan quality and on the risk of secondary tumors in patients with pituitary adenoma

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