Benign prostatic hyperplasia (BPH) is a frequent cause of lower urinary tract symptoms (LUTS) in men. One fourth of men older than 70 have moderate to severe LUTS that impair their quality of life (QOL). Prostatic artery embolization (PAE) is a new minimally invasive technique proven effective in reducing LUTS comparable to the mainstay treatment - the transurethral resection of the prostate (TURP).

The most common side effect of PAE is a collection of inflammation-related symptoms known as the postembolization syndrome (PES). The symptoms include pelvic pain, fever, nausea, and transient worsening of LUTS (painful and difficult urination). PES is a self-limiting condition that is treated symptomatically with painkillers and antipyretics. However, PES can be so severe that the patients experience high fever, shivers, dysuria and urgency mimicking a septicemia from the urinary tract. It is a clinical challenge to avoid exposure to unnecessary antibiotics treatment in those situations. A subset of patients may need admission to the hospital for observation, especially in case of fever. Usually, PES resolves within a week after PAE. Steroids have been successfully used to reduce the incidence and severity of PES after a number of procedures in interventional radiology. The investigators postulate that steroids can have a similar effect in reducing PES after PAE. In this study, the efficacy of single high dose postprocedural dexamethasone (DEXA) administration in reducing PES after PAE will be evaluated, compared to placebo.

Inclusion Criteria:

• Diagnosis of LUTS secondary to BPH refractory to/contraindicated for medical treatment or not patient preference
• Moderate to severe urinary symptoms on IPSS (IPSS score 8 or over)
• Qmax <=15ml/sec, based on flowmetry
• Unsuitable for TURP or refuses surgery
• Ability to understand and the willingness to sign an informed consent
• Prostate volume > 80 milliliters
• Men with low-risk prostate cancer (T1c, Gleason score <=6 on a maximum of 3 biopsies) who have LUTS due to a large BPH component are eligible
• Indwelling or intermittent catheter is allowed

Exclusion Criteria:

• History of bladder cancer
• Previous pelvic radiation for cancer treatment
• Current bladder stones
• Significant bladder diverticula
• Current urethral strictures or bladder neck contracture
• Neurologic conditions such as multiple sclerosis, Parkinson's disease and other neurological diseases known to affect bladder function
• Neurogenic bladder without obstruction
• Active urinary tract infection at the time of intervention unless in case of regular catheter dependence and thought to represent colonization
• Documented bacterial prostatitis in the last year
• Severe atheromatous disease or other pathology preventing catheter-based intervention (as rated on CT angiography by an interventional radiologist)
• Allergy to iodinated contrast media
• Renal failure (eGFR < 30ml/min)
• High bleeding risk (spontaneous INR > 1.6)
• Contraindication to conscious sedation (if requested by participant)
• Allergy to dexamethasone
• Positive HIV, hepatitis B or C
• Immunological disease (except topically treated skin or respiratory diseases)
• Glaucoma
• Active peptic or duodenal ulcer
• Systemic fungal infections
• Immunosuppressive treatment (systemic)
• Current treatment of cancer (except low risk prostate cancer)

The results of this trial will be submitted for publication in a peer reviewed journal, in addition to reports at appropriate specialist conferences. The results of the trial will be disseminated regardless of the direction of effect.

The investigators intend to share de-identified individual participant data that underlie the results reported in the published article following reasonable requests to the principal investigator, and if in accordance with Danish law.

Data will be made available beginning 9 months and ending 36 months after article publication.

Data will be made available to qualified scientific researchers who provide a methodologically sounds proposal following reasonable requests to the principal investigator.