Multiparametric imaging guided HDR interventional radiotherapy (brachytherapy) boost in localized prostate cancer: a multidisciplinary experience.

OBJECTIVE: The aim of this study was to report a monoinstitutional multidisciplinary experience about the use of multiparametric imaging to identify the areas with higher risk of relapse in localized prostate cancer, with the purpose of allowing a biologically planned target dose escalation. PATIENTS AND METHODS: We performed a retrospective evaluation of patients diagnosed with prostate cancer who received treatments at our Interventional Oncology Center with interstitial interventional radiotherapy from 2014 to 2022. Inclusion criteria were histologically confirmed localized prostate cancer; and National Comprehensive Cancer Network (NCCN) risk class unfavorable intermediate or high/very high risk. The diagnostic work-up included multiparametric Magnetic resonance imaging (MRI), multiparametric Transrectal ultrasound (TRUS), Positron Emission Tomography Computed Tomography (PET-CT) with choline or PSMA (or alternatively bone scan). All patients were assessed and received one treatment with interstitial high-dose-rate interventional radiotherapy (brachytherapy) delivering external beam radiotherapy (46 Gy). All procedures were performed using transrectal ultrasound guidance under general anesthesia and the prescribed doses were 10 Gy to the whole prostate, 12 Gy to the peripheral zone and 15 Gy to the areas at risk. RESULTS: We report the data of 21 patients who were considered for the statistical analysis with a mean age of 62.5 years. The mean PSA nadir was 0.03 ng/ml (range 0-0.09). So far, no biochemical nor radiological recurrences have been recorded in our series. Regarding acute toxicity, the most commonly reported side effects were G1 urinary in 28.5% of patients and G2 urinary in 9.5%; all recorded acute toxicities resolved spontaneously. CONCLUSIONS: We present a real-life experience of biologically planned local dose escalation by interventional radiotherapy (brachytherapy) boost, followed by external beam radiotherapy in patients with intermediate unfavorable- or high/very high risk. The local control and the biochemical control rates are proved to be excellent and the toxicity profile tolerable.

The effects of loperamide, or loperamide plus simethicone, on the distribution of gut water as assessed by MRI in a mannitol model of secretory diarrhoea.

BACKGROUND: Loperamide (LOP) is an anti-diarrhoeal agent which is thought to act largely by slowing transit with an uncertain effect on the fluid content of the small and large bowel in humans. Adding simethicone (SIM) to LOP improves its efficacy, but the mechanism of interaction is unclear. Novel MRI techniques to assess small bowel water content (SBWC) have shown that mannitol solutions markedly increase SBWC and can be used as a model of diarrhoea. AIM: We aimed to use quantitative MRI techniques to compare the actions in the gut of LOP and LOP + SIM in a model of secretory diarrhoea using mannitol. METHODS: A total of 18 healthy volunteers ingested capsules containing placebo (PLA) or 12 mg LOP or 12 mg LOP + 125 mg SIM. After 100 min they were given a drink containing 5% mannitol in 350 mL of water. They underwent baseline fasting and postprandial serial MRI scans at 45 min intervals for 4.5 h after ingesting the drink. A range of MRI sequences was acquired to image the gut. RESULTS: LOP and LOP + SIM significantly accelerated gastric emptying (P < 0.03) and reduced SBWC during the late phase (135-270 min after mannitol ingestion), P < 0.009, while delaying arrival of fluid in the ascending colon (AC). The relaxation time T2 of the contents of the AC was reduced by both drugs (P < 0.0001). CONCLUSIONS: LOP and LOP + SIM accelerate gastric emptying, but reduce small bowel water content which may contribute to the delay in oral-caecal transit and overall anti-diarrhoeal effect.