MRI-guided focal boost to dominant intraprostatic lesion using volumetric modulated arc therapy in prostate cancer. Results of a phase II trial.

OBJECTIVE: To determine morphological and biological control as well as toxicity and quality of life (QoL) of men with localized prostate cancer (PCa) treated with MRI-guided focal boost radiotherapy. MATERIAL AND METHODS: 30 patients with PCa and a visible dominant intraprostatic lesion (DIL) identified on mpMRI were included in a prospective Phase II trial. Matching point registration of planning CT and T2W, diffusion-weighted and a gradient-recalled echo (GRE) MRI images made in treatment position was used for prostate and tumour delineation. Treatment consisted on 35 daily fractions of 2.17 Gy with a concomitant focal boost to the DIL of 2.43 Gy using volumetric modulated arc therapy (VMAT) and image-guided radiation therapy (IGRT) with intraprostatic fiducial markers. Biochemical failure was analysed using PSA nadir +2 ng/mL criteria and local control using mpMRI evaluation at 6-9 months following RT. Acute and late toxicity were defined according to CTCAE v.4.0 and RTOG/EORTC scales and QoL was assessed using IPSS, EPIC short-form and UCLA-PCI questionnaires. RESULTS: The median radiation dose to the prostate was 77.6 Gy (IQR 77.3-78.1), and to the DIL was 85.5 Gy (IQR 85.0-86.0). With a median follow up of 30.0 months (IQR 25.5-40.27), all patients remain free of biochemical relapse. An mpMRI complete response was observed in 25 patients during the first post-treatment evaluation at 6 months. The remaining five patients achieved a complete disappearance of the DIL both on T2 and DWI on the second mpMRI performed at 9 months following treatment. Six out of 30 (20%) patients presented acute Grade 2 urinary toxicity with no Grade 3 acute complications. Acute rectal toxicity was only found in 2 (6.6%) patients (both Grade 1). Only late Grade 1 urinary and rectal complications were observed in 3/30 patients, respectively, with no Grade 2 or more late toxicity. The urinary, bowel and sexual bother EPIC scores were slightly and insignificantly increased in the first 3 months post-treatment, returning to normal afterwards. CONCLUSIONS: mpMRI-guided focal boost using VMAT hypofractionated technique is associated with an excellent morphological and functional response control and a safe toxicity profile. ADVANCES IN KNOWLEDGE: In the present trial, we examined the potential role of mpMRI for radiological assessment (functional and morphological) of treatment response in high-risk prostate cancer patients treated with MRI-guided focal radiotherapy dose intensification to dominant Intraprostatic lesion.

Tumor estromal gastrointestinal: diagnóstico y pronóstico / Gastrointestinal stromal tumor: diagnosis and prognosis

Los tumores estromales gastrointestinales (GIST) son tumores mesenquimatosos derivados de una célula precursora. Tiene capacidad de diferenciación miogénica o neurogénica y se caracterizan por la expresión de proteína KIT (factor de crecimiento de la tirosincinasa). Clínicamente presentan un comportamiento biológico variable. Presentamos ocho casos de GIST, describiendo su presentación radiológica en tomografía computarizada (TC) así como los criterios de benignidad y malignidad más aceptados en la bibliografía. Además, presentamos la respuesta de uno de ellos con metástasis al diagnóstico, tras tratamiento con inhibidor de la tirosincinasa. (AU)