Targeted High-Dose Radiation Therapy for Newly Diagnosed Prostate Cancer—A Study Investigating a New, Precise Radiation Therapy Method (HypoFocal SBRT Study)

Prostate cancer is one of the most common cancers in men. The risk of developing this disease increases with age, a family history of the disease, and hormonal factors. This cancer usually develops slowly in the prostate, a small gland located below the bladder that plays a role in reproduction. The disease often goes unnoticed for a long time because it initially causes no symptoms. In more aggressive forms, treatment is necessary—for example, through surgery, radiation therapy, or anti-hormone therapy. Various methods are available for treating prostate cancer with radiation therapy, such as moderately hypofractionated radiation therapy (MHRT) or stereotactic body radiation therapy (SBRT).

The goal of this Phase 3 study is to compare two radiation therapy methods (MHRT and SBRT). MHRT is the established standard method, in which the entire prostate is irradiated over approximately four weeks in 20 sessions. The radiation dose in each session is slightly higher than with conventional long-term radiation therapy, but it is still well tolerated. The goal is to treat the entire prostate uniformly, even if the tumor is located only in a specific area, since tiny tumor cells that are not visible on imaging may be present in other parts of the gland. These cancer cells could grow and later lead to a relapse if left untreated. Therefore, as a precaution, the entire prostate is irradiated to ensure that all potentially affected cells are targeted. This increases the chance of cure and reduces the risk of the cancer returning.

In contrast, SBRT relies on particularly precise and targeted high-dose radiation. Using modern imaging techniques such as MRI (magnetic resonance imaging) and PSMA-PET/CT (prostate-specific membrane antigen positron emission tomography/computed tomography), the exact location of the tumor within the prostate is determined. Only this tumor area then receives a particularly high radiation dose, while the surrounding tissue is spared. As a result, only five sessions over the course of three weeks are required. This method is shorter, more comfortable, and, due to the targeted treatment, could be associated with fewer side effects and be more effective. In the study, patients are randomly assigned to one of two treatment groups: one receives standard radiation therapy (MHRT), and the other receives the novel targeted high-dose radiation therapy (SBRT). The primary endpoint of the study is recurrence-free survival (RFS). The study is being conducted at multiple centers in Germany, Austria, Switzerland, and Cyprus. Quality of life will be monitored for up to approximately 7.5 years after the start of therapy using questionnaires.

Men aged 18 and older with histologically confirmed high-risk prostate cancer are eligible to participate. This refers to specific tumor characteristics that indicate aggressive growth and an increased risk of recurrence or metastasis. Additional requirements include good overall health, normal urinary function, and prior imaging studies (PSMA-PET/MRI or mpMRI scans). An mpMRI scan (multiparametric magnetic resonance imaging) is a specialized form of magnetic resonance imaging (MRI) used for particularly accurate imaging in prostate cancer. Patients with tumor metastases, a history of radiation therapy, prostate surgery, or serious pre-existing conditions are excluded.