Stereotactic body radiation therapy for liver metastasis from colorectal cancer: size matters.

PURPOSE: We analysed our initial experience with SBRT in liver metastasis from colorectal cancer at our institution. MATERIALS AND METHODS: Between January/2014 and December/2017, 22 patients with 31 LMCCR were treated. Local control (LC) was assessed using the Kaplan-Meier and log-rank tests. We analysed potential prognostic factors for LC: sex, PTV size, number of LM and the radiation scheme. RESULTS: Median age: 69 years. Prior chemotherapy or local liver treatments: 81.8% and 63.6% of patients, respectively. SBRT consisted of 3 × 20 Gy (42.9%) and 3 × 15 Gy (31.4%). There were 88.5% responses (57.1% CR and 31.4% PR). Median follow-up was 30 months. LC per lesion at 12 and 24 months was 85.3% and 61.8%, respectively. Tumour volumes > 30 cc correlated with worsened 2-year-control rates (90% vs 34.5%) (p = 0.005). There was only a patient with CTC-grade 3 toxicity. CONCLUSIONS: Liver SBRT is a safe and effective treatment that achieves high local control rates. We found a significant correlation between larger LMCRC and worse local control.

Influence of different treatment techniques and clinical factors over the intrafraction variation on lung stereotactic body radiotherapy

Purpose: In the present study we compared three different Stereotactic body radiation therapy (SBRT) treatment delivery techniques in terms of treatment time (TT) and their relation with intrafraction variation (IFV). Besides that, we analyzed if different clinical factors could have an influence on IFV. Finally, we appreciated the soundness of our margins. Materials and methods: Forty-five patients undergoing SBRT for stage I lung cancer or lung metastases up to 5 cm were included in the study. All underwent 4DCT scan to create an internal target volume (ITV) and a 5 mm margin was added to establish the planning target volume (PTV). Cone-beam CTs (CBCTs) were acquired before and after each treatment to quantify the IFV. Three different treatment delivery techniques were employed: fixed fields (FF), dynamically collimated arcs (AA) or a combination of both (FA). We studied if TT was different among these modalities of SBRT and whether TT and IFV were correlated. Clinical data related to patients and tumors were recorded as potential influential factors over the IFV. Results: A total of 52 lesions and 147 fractions were analyzed. Mean IFV for x-, y- and z-axis were 1 ± 1.16 mm, 1.29 ± 1.38 mm and 1.17 ± 1.08 mm, respectively. Displacements were encompassed by the 5 mm margin in 96.1 % of fractions. TT was significantly longer in FF therapy (24.76 ± 5.4 min), when compared with AA (15.30 ± 3.68 min) or FA (17.79 ± 3.52 min) (p < 0.001). Unexpectedly, IFV did not change significantly between them (p = 0.471). Age (p = 0.003) and left vs. right location (p = 0.005) were related to 3D shift ≥2 mm. In the multivariate analysis only age showed a significant impact on the IFV (OR = 1.07, p = 0.007). Conclusions: The choice of AA, FF or FA does not impact on IFV although FF treatment takes significantly longer treatment time. Our immobilization device offers enough accuracy and the 5 mm margin may be considered acceptable as it accounts for more than 95 % of tumor shifts. Age is the only clinical factor that influenced IFV significantly in our analysis

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Influence of different treatment techniques and clinical factors over the intrafraction variation on lung stereotactic body radiotherapy.

PURPOSE: In the present study we compared three different Stereotactic body radiation therapy (SBRT) treatment delivery techniques in terms of treatment time (TT) and their relation with intrafraction variation (IFV). Besides that, we analyzed if different clinical factors could have an influence on IFV. Finally, we appreciated the soundness of our margins. MATERIALS AND METHODS: Forty-five patients undergoing SBRT for stage I lung cancer or lung metastases up to 5 cm were included in the study. All underwent 4DCT scan to create an internal target volume (ITV) and a 5 mm margin was added to establish the planning target volume (PTV). Cone-beam CTs (CBCTs) were acquired before and after each treatment to quantify the IFV. Three different treatment delivery techniques were employed: fixed fields (FF), dynamically collimated arcs (AA) or a combination of both (FA). We studied if TT was different among these modalities of SBRT and whether TT and IFV were correlated. Clinical data related to patients and tumors were recorded as potential influential factors over the IFV. RESULTS: A total of 52 lesions and 147 fractions were analyzed. Mean IFV for x-, y- and z-axis were 1 ± 1.16 mm, 1.29 ± 1.38 mm and 1.17 ± 1.08 mm, respectively. Displacements were encompassed by the 5 mm margin in 96.1 % of fractions. TT was significantly longer in FF therapy (24.76 ± 5.4 min), when compared with AA (15.30 ± 3.68 min) or FA (17.79 ± 3.52 min) (p < 0.001). Unexpectedly, IFV did not change significantly between them (p = 0.471). Age (p = 0.003) and left vs. right location (p = 0.005) were related to 3D shift ≥2 mm. In the multivariate analysis only age showed a significant impact on the IFV (OR = 1.07, p = 0.007). CONCLUSIONS: The choice of AA, FF or FA does not impact on IFV although FF treatment takes significantly longer treatment time. Our immobilization device offers enough accuracy and the 5 mm margin may be considered acceptable as it accounts for more than 95 % of tumor shifts. Age is the only clinical factor that influenced IFV significantly in our analysis.

[Description of latest generation equipment in external radiotherapy]. / Descripción de equipos de última generación en radioterapia externa.

Both the planning systems and the form of administering radiotherapy have changed radically since the introduction of 3D planning. At present treatment planning based on computerised axial tomography (CAT) images is standard practice in radiotherapy services. In recent years lineal accelerators for medical use have incorporated technology capable of administering intensity modulated radiation beams (IMRT). With this mode distributions of conformed doses are generated that adjust to the three dimensional form of the white volume, providing appropriate coverage and a lower dose to nearby risk organs. The use of IMRT is rapidly spreading amongst radiotherapy centres throughout the world. This growing use of IMRT has focused attention on the need for greater control of the geometric uncertainties in positioning the patient and control of internal movements. To this end, both flat and volumetric image systems have been incorporated into the treatment equipment, making image-guided radiotherapy (IGRT) possible. This article offers a brief description of the latest advances included in the planning and administration of radiotherapy treatment.

[Heavy particle radiation therapy]. / Radioterapia con partículas pesadas.

The characteristics of radiation formed by heavy particles make it a highly useful tool for therapeutic use. Protons, helium nuclei or carbon ions are being successfully employed in radiotherapy installations throughout the world. This article sets out the physical and technological foundations that make these radiation particles suitable for attacking white volume, as well as the different ways of administering treatment. Next, the main clinical applications are described, which show the therapeutic advantages in some of the pathologies most widely employed in proton and hadron therapy centres at present. Under continuous study, the clinical use of heavy particles appears to be an enormously promising path of advance in comparison with classical technologies, both in tumour coverage and in reducing dosages in surrounding tissue.

Descripción de equipos de última generación en radioterapia externa / Description of latest generation equipment in external radiotherapy

Tanto los sistemas de planificación como la formade administración de los tratamientos radioterápicoshan cambiado radicalmente desde la introducción dela planificación tridimensional 3D. En la actualidad laplanificación de los tratamientos basada en imágenesde tomografía axial computarizada (TAC) es el estándarde los servicios de radioterapia. En los últimos años losaceleradores lineales para uso médico, han incorporandotecnología capaz de administrar haces de tratamientode intensidad modulada, IMRT. Con esta modalidadse generan distribuciones de dosis altamente conformadasque se ajustan a la forma tridimensional del volumenblanco, proporcionando una cobertura adecuaday una menor dosis a los órganos de riesgo cercanos.El uso de la IMRT rápidamente se está extendiendoentre los centros de radioterapia de todo el mundo.Este creciente uso de la IMRT ha focalizado la atenciónen la necesidad de un mayor control de las incertidumbresgeométricas en el posicionamiento del paciente yun control de los movimientos internos, por ello se hanincorporado a los equipos de tratamiento sistemas deimagen tanto planar como volumétrica, que posibilitanuna radioterapia guiada por la imagen, IGRT. En este trabajose presenta una breve descripción de los últimosavances incorporados a la planificación y administracióndel tratamiento radioterápico(AU)

Both the planning systems and the form of administeringradiotherapy have changed radically since theintroduction of 3D planning. At present treatment planningbased on computerised axial tomography (CAT)images is standard practice in radiotherapy services.In recent years lineal accelerators for medical use haveincorporated technology capable of administering intensitymodulated radiation beams (IMRT). With thismode distributions of conformed doses are generatedthat adjust to the three dimensional form of the whitevolume, providing appropriate coverage and a lowerdose to nearby risk organs.The use of IMRT is rapidly spreading amongst radiotherapycentres throughout the world. This growinguse of IMRT has focused attention on the need forgreater control of the geometric uncertainties in positioningthe patient and control of internal movements.To this end, both flat and volumetric image systemshave been incorporated into the treatment equipment,making image-guided radiotherapy (IGRT) possible.This article offers a brief description of the latest advancesincluded in the planning and administration ofradiotherapy treatment(AU)

Radioterapia con partículas pesadas / Heavy particle radiation therapy

Las características de la radiación constituida porpartículas pesadas la convierten en una herramientamuy útil para el uso terapéutico. Los protones, losnúcleos de helio o los iones de carbono están siendoempleados con éxito en instalaciones radioterápicasde todo el mundo. En este trabajo se exponen los fundamentosfísicos y tecnológicos que convierten a estaspartículas en radiación adecuada para atacar losvolúmenes blanco, así como las distintas maneras deadministrar tratamientos. Posteriormente se describenlas principales aplicaciones clínicas que muestran lasventajas terapéuticas en algunas de las patologías másempleadas en centros de protón y hadrón-terapia en laactualidad. En continuo estudio, el uso clínico de partículaspesadas se presenta como una vía de avanceenormemente prometedora frente a las tecnologías clásicas,tanto en cobertura tumoral como en reducciónde dosis en el tejido circundante(AU)

The characteristics of radiation formed by heavyparticles make it a highly useful tool for therapeuticuse. Protons, helium nuclei or carbon ions are beingsuccessfully employed in radiotherapy installationsthroughout the world. This article sets out the physicaland technological foundations that make these radiationparticles suitable for attacking white volume, aswell as the different ways of administering treatment.Next, the main clinical applications are described,which show the therapeutic advantages in some of thepathologies most widely employed in proton and hadrontherapycentres at present. Under continuous study,the clinical use of heavy particles appears to be anenormously promising path of advance in comparisonwith classical technologies, both in tumour coverageand in reducing dosages in surrounding tissue(AU)