Evaluación de Errores de Posicionamiento en los 6 Grados de Libertad en Pacientes con Cáncer de próstata tratados con radioterapia

Resumen

Objetivos Determinar la magnitud de los errores de posicionamiento en los 6 grados de libertad y calcular el Margen a CTV para un protocolo adaptado en pacientes con cáncer de próstata temprano y localmente avanzado en un centro de referencia en Colombia.

Métodos Se realizó un estudio observacional prospectivo en 61 pacientes con cáncer de próstata tratados con radioterapia en el Centro Javeriano de Oncología del Hospital Universitario San Ignacio durante el 2018, con toma de imágenes volumétricas de rayos x durante los primeros 3 días de tratamiento obteniéndose un promedio en errores traslacionales y rotacionales. Posteriormente se tomaron imágenes semanales. Además, se realizó el cálculo del margen al PTV y variaciones en vejiga y recto durante el tratamiento.

Resultados Un total de 508 imágenes fueron registradas durante las 8 semanas de tratamiento, los errores traslacionales y rotacionales tuvieron un comportamiento alrededor de cero sin diferencias significativas inclusive en pacientes con IMC > = 25. También se calculó el margen al PTV encontrándose entre 5 y 8 mm, en cuanto a las medidas de vejiga y recto no se encontraron diferencias estadísticamente significativas en las imágenes adquiridas durante la radioterapia.

Conclusiones De acuerdo a los datos encontrados en este estudio, una adecuada reproducibilidad en paciente con cáncer de próstata puede ser encontrada usando el método de registro rígido de la anatomía pélvica ósea, promediando las 3 primeras imágenes y posteriormente con imágenes semanales, en centros con alta demanda de pacientes garantizando así una adecuada precisión del tratamiento.

Abstract

Objectives To determine the magnitude of the positioning errors in the 6 degrees of freedom and calculate the Margin to CTV for an adapted protocol in patients with early and locally advanced prostate cancer in a reference center in Colombia.

Methods A prospective observational study was performed in 61 prostate cancer patients treated with radiotherapy at the Javeriano Oncology Center of the San Ignacio University Hospital during 2018, with volumetric X-ray imaging during the first 3 days of treatment obtaining a average in translational and rotational errors. Subsequently, weekly images were taken. In addition, the calculation of the margin to the PTV and variations in bladder and rectum during the treatment was performed.

Results A total of 508 images were recorded during the 8 weeks of treatment, translational and rotational errors had a behavior around zero without significant differences even in patients with BMI > = 25. The margin to the PTV was also calculated between 5 and 8 mm, in terms of bladder and rectum measurements, no statistically significant differences were found in the images acquired during radiotherapy.

Conclusions According to the data found in this study, an adequate reproducibility in a patient with prostate cancer can be found using the method of rigid registration of the pelvic bone anatomy, averaging the first 3 images and subsequently with weekly images, in centers with high patient demand guaranteeing adequate treatment accuracy.

Palabras clave

radioterapia - cáncer de próstata - error de posicionamiento - márgenes

Keywords

radiation therapy - prostate cáncer - positioning error - margins

Publikationsverlauf

Eingereicht: 21. Januar 2020

Angenommen: 17. Juni 2020

Artikel online veröffentlicht:
13. Januar 2021

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