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VMAT is a powerful technique to deliver hypofractionated prostate treatments. The lack of correlations between usual 2D pretreatment QA results and the clinical impact of possible mistakes has allowed the development of 3D verification systems. Dose determination on patient anatomy has provided clinical predictive capability to patient-specific QA process. Dose-volume metrics, as evaluation criteria, should be replaced or complemented by radiobiological indices. These metrics can be incorporated into individualized QA extracting the information for response parameters (gEUD, TCP, NTCP) from DVHs. The aim of this study is to assess the role of two 3D verification systems dealing with radiobiological metrics applied to a prostate VMAT QA program. Radiobiological calculations were performed for AAPM TG-166 test cases. Maximum differences were 9.3% for gEUD, -1.3% for TCP, and 5.3% for NTCP calculations. Gamma tests and DVH-based comparisons were carried out for both systems in order to assess their performance in 3D dose determination for prostate treatments (high-, intermediate-, and low-risk, as well as prostate bed patients). Mean gamma passing rates for all structures were bet-ter than 92.0% and 99.1% for both 2%/2 mm and 3%/3 mm criteria. Maximum discrepancies were (2.4% ± 0.8%) and (6.2% ± 1.3%) for targets and normal tis-sues, respectively. Values for gEUD, TCP, and NTCP were extracted from TPS and compared to the results obtained with the two systems. Three models were used for TCP calculations (Poisson, sigmoidal, and Niemierko) and two models for NTCP determinations (LKB and Niemierko). The maximum mean difference for gEUD calculations was (4.7% ± 1.3%); for TCP, the maximum discrepancy was (-2.4% ± 1.1%); and NTCP comparisons led to a maximum deviation of (1.5% ± 0.5%). The potential usefulness of biological metrics in patient-specific QA has been explored. Both systems have been successfully assessed as potential tools for evaluating the clinical outcome of a radiotherapy treatment in the scope of pretreatment QA.

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El antígeno prostático específico (PSA) es la principal herramienta en el seguimiento de los pacientes con cáncer de próstata tras un tratamiento definitivo. Es ampliamente empleado como un marcador precoz de respuesta al tratamiento. La recidiva bioquímica predice el desarrollo de metástasis a distancia y la mortalidad cáncer-específica. En 1996, la Sociedad Americana de Oncología Radioterápica (ASTRO) creó una definición de fracaso bioquímico tras Radioterapia, que consistía en 3 elevaciones consecutivas tras el nadir. A medida que se ganó en experiencia y con la maduración de los datos con mayores periodos de seguimiento, surgieron deficiencias y controversias, por lo que se propusieron otras definiciones alternativas con resultados más consistentes. En vista de las críticas recibidas, un segundo consenso tuvo lugar en 2005, con "nadir + 2 ng/ml" aceptada como definición estándar. La historia natural y cinética de PSA así como diferentes definiciones de fracaso bioquímico tras tratamiento de radioterapia externa y/o braquiterapia son revisadas en el siguiente artículo(AU)

Prostate specific antigen (PSA) is the main tool in the follow-up of prostate cancer patients after definitive therapy. It's widely used as an early marker to value treatment success. Biochemical recurrence predicts metastatic disease progression and prostate cancer-specific mortality. In 1996, the American Society for Therapeutic Radiology and Oncology (ASTRO) provided a definition of biochemical failure after radiotherapy, based on three consecutive increases in PSA after nadir. As more experience was gained using the proposed definition and follow up duration in the PSA era matured, deficiencies and controversial issues emerged, so more recently proposed candidate definitions have provided consistent outcome. In view of the criticisms, a second consensus conference was held on 2005, with "nadir + 2 ng/ml" accepted as standard definition. The natural history and evidence of PSA kinetic parameters and different definitions of biochemical failure after external beam radiation therapy and/or brachytherapy are reviewed in the following article(AU)

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La RT adyuvante ha demostrado ser más eficaz, en aquellos pacientes con alto riesgo de recaída, que la RT de rescate cuando ya se ha producido dicha recaída. Para optimizar su empleo se debe identificar el subgrupo de pacientes con mayor riesgo de enfermedad microscópica residual tras la cirugía, ya que en estos la probabilidad de fracaso bioquímico a los 5-10 años puede llegar hasta un 60%. Existen muchos estudios al respecto en los que se identifican estos factores, que en general son: la existencia de márgenes positivos, la afectación capsular o de vesículas seminales (T3a-b). De todos ellos, parece que la presencia de márgenes positivos es el predictor más potente de recaída. En cuanto al tratamiento radioterápico a administrar existe variabilidad en la dosis administrada y el volumen a tratar. En general la dosis en la mayoría de las series es ≥ 60 Gy, llegando algunos autores hasta 70 Gy. En cuanto a la asociación o no de hormonoterapia (HT) a la radioterapia adyuvante es un tema de debate y de momento no existen resultados de estudios que demuestren un beneficio suficiente, por lo que habría que individualizar sopesando potenciales ventajas en los pacientes de alto riesgo frente a los efectos secundarios(AU)

Adjuvant radiotherapy (RT) has proven to be more effective in patients at high risk of relapse than salvage RT when this relapse occurs. To optimize its use we must identify the subset of patients at greater risk of residual microscopic disease after surgery, since in them the likelihood of 5-10 year biochemical failure can reach 60%. There are many studies on the subject in which these factors are identified, which in general are: presence of positive margins and capsular or seminal vesicle involvement (T3a-b). Of these, it seems that the presence of positive margins is the most powerful predictor of relapse. With regard to radiotherapy, there is variability in the dose to give and volume treated. In general, the dose in most series is ≥ 60 Gy, reaching some authors up to 70 Gy. As to the association or not hormone therapy (HT) and adjuvant radiotherapy, it is a subject of debate and so far no results of studies demonstrate a sufficient benefit, so it should be individualized, weighing potential benefits in high risk patients against side effects(AU)

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OBJECTIVES: Recently it has been reported in the EORTC (European Organisation for Research and Treatment of Cancer) trial 22911 and the SWOG (Southwest Oncology Group) 8794, the evidence that radiotherapy (RT) is an effective treatment after the prostatectomy in patients with high risk of biochemical failure. We analyze predictor factors of biochemical relapse and the potential benefits induced by rescue treatment are the main purposes of our study. METHODS: From 1993 to 2003, 597 prostatectomy were followed at Hospital Universitario Gregorio Marañón de Madrid, identifying 166 patients (p) (28%) of biochemical failure (defined as PSA > or = 0'5 ng/ml, including post-surgical persistent values). 42 p received RT (78% due to delayed PSA relapse). The median total dose was 66 Gy [60-74]. RESULTS: Clinical variables: Median age: 68 years [49-80], median PSA at diagnosis: 29,8 ng/ml [2,6475]; presurgical Gleason > or = 7: 65%. Histological variables: Prostatectomy induces stage migration to superior T (pT3-T4: 95%) and Gleason categories (> or =7: 81%). 83% of relapsed p had positive margins and 90% had pT3-pT4. OUTCOME VARIABLES: median time to biochemical recurrence was 22,2 months. Median time interval between biochemical failure and RT was 10,5 months. Overall survival (5 years) was 86 +/- 6%. Freedom-from-biochemical failure at 5 years was 76 +/- 4%. RT had poor survival in p with PSA > 2 ng/ml pre-RT (p = 0.03), post-prostatectomy persistant disease (p = 0.05) and Gleason score > or = 7 (p = 0.01). No increased grade 3-4 uro-rectal toxicity was observed. CONCLUSIONS: RT after prostatectomy improves freedom-from-biochemical failure in p with PSA values below 2 ng/ml. In our experience, Gleason score > or = 7 is a negative predictor of response. There is no severe toxicity in our series. Improvement of the staging presurgery, the role of the adjuvant androgen deprivation and selection of patients for adjuvant RT focus current studies on treatment after prostatectomy.

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Objetivo: Recientemente se han comunicado firmes evidencias por la EORTC (European Organisation for Research and Treatment of Cancer -ensayo 22911) y el SWOG (Southwest Oncology Group- ensayo 8794), señalando que la radioterapia (RT) es un tratamiento eficaz tras la prostatectomía en pacientes con alto riesgo de fracaso bioquímico. Definir el momento óptimo para su administración e identificar factores de riesgo predictivos de recidiva, son objetivos transcendentes para guiar la práctica asistencial. Métodos: Desde 1993 hasta 2003, 597 pacientes fueron tratados con prostatectomía radical en el Hospital General Universitario Gregorio Marañón y áreas de referencia asistencial. 166 pacientes (28%) desarrollaron una recidiva bioquímica (definida como PSA ≥0,5 ng/ml e incluyendo aquellos casos con persistencia tumoral). Cuarenta y dos, recibieron tratamiento con RT (78% tras fallo bioquímico). La dosis media de RT fue de 66 Gy [60-74]. Resultados: Variables clínicas: Edad media: 68 años [49-80], media del PSA al diagnóstico: 29,8 ng/ml [2,6-475], Gleason prequirúrgico ≥7: 65%. Variables patológicas: Tras la prostatectomía, los pacientes tenían datos de mayor agresividad histológica que la definida previamente en las biopsias, apareciendo Gleason ≥7 en el 81% de los pacientes. El 83% a su vez tenían borde afecto y en el 90% de los casos el estadio era pT3-pT4. Variables evolutivas: El tiempo medio de aparición de la recidiva bioquímica fue de 22,2 meses, con un intervalo de 10,5 meses desde el diagnóstico hasta el inicio de la RT. La SG fue de 86±6 % a los 5 años y la Supervivencia Libre de Fracaso Bioquímico (SLFB) fue de 76±4% a los 5 años. Los factores predisponentes para la recidiva fueron: PSA >2 ng/ml al inicio de la RT (p=0,03), persistencia tumoral (p=0,05) y Gleason ≥7 tras la prostatectomía (p=0,01). No se observó un aumento de la toxicidad grado 3 y 4 en los pacientes tratados con RT. Conclusiones: La RT tras prostatectomía es un tratamiento eficaz de rescate tras recidiva bioquímica o persistencia cuando el PSA no supera los 2 ng/ml. En nuestra serie, el Gleason ≥7 es un factor adverso de respuesta a la RT de rescate. No existe un aumento de la toxicidad severa. La mejora de las técnicas de estadificación prequirúrgica, el papel de la hormonoterapia adyuvante y la selección de los pacientes para RT adyuvante centran los estudios actuales de los tratamientos tras prostatectomía (AU)

Objectives: Recently it has been reported in the EORTC (European Organisation for Research and Treatment of Cancer) trial 22911 and the SWOG (Southwest Oncology Group) 8794, the evidence that radiotherapy (RT) is an effective treatment after the prostatectomy in patients with high risk of biochemical failure. We analyze predictor factors of biochemical relapse and the potential benefits induced by rescue treatment are the main purposes of our study. Methods: From 1993 to 2003, 597 prostatectomy were followed at Hospital Universitario Gregorio Marañón de Madrid, identifying 166 patients (p) (28%) of biochemical failure (defined as PSA ≥0’5 ng/ml, including post-surgical persistent values). 42 p received RT (78% due to delayed PSA relapse). The median total dose was 66 Gy [60-74]. Results: Clinical variables: Median age: 68 years [49-80], median PSA at diagnosis: 29,8 ng/ml [2,6-475]; presurgical Gleason ≥7: 65%. Histological variables: Prostatectomy induces stage migration to superior T (pT3-T4: 95%) and Gleason categories (≥7: 81%). 83% of relapsed p had positive margins and 90% had pT3-pT4. Outcome variables: median time to biochemical recurrence was 22,2 months. Median time interval between biochemical failure and RT was 10,5 months. Overall survival (5 years) was 86±6%. Freedom-from-biochemical failure at 5 years was 76±4%. RT had poor survival in p with PSA >2 ng/ml pre-RT (p=0,03), post-prostatectomy persistant disease (p=0,05) and Gleason score ≥7 (p=0,01). No increased grade 3-4 uro-rectal toxicity was observed. Conclusions: RT after prostatectomy improves freedom-from-biochemical failure in p with PSA values below 2 ng/ml. In our experience, Gleason score ≥7 is a negative predictor of response. There is no severe toxicity in our series. Improvement of the staging presurgery, the role of the adjuvant androgen deprivation and selection of patients for adjuvant RT focus current studies on treatment after prostatectomy (AU)

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