Irradiation for prostate cancer

Introduction

Prostate cancer is the most common tumor in men. Fortunately, many different treatment options are available today. One of these options is radiation therapy, which, if diagnosed early, can lead to complete recovery of the patient.

In an advanced stage, radiation can relieve tumor-associated symptoms. But there are also different approaches to radiation therapy. Different radiation and different methods can be used.

What methods of irradiation are there?

In the classical radiation therapy, the percutaneous radiotherapy, the skin is irradiated from the outside. In the case of a localized tumor, radiation alone is usually sufficient. In the case of metastases, hormone therapy is also required.

Besides percutaneous radiotherapy, brachytherapy is also available. In this case the prostate is irradiated from the inside. For this purpose, a radioactive source is placed in the tissue.

There are two methods of brachytherapy. In the first procedure, LDR seeds, radioactive sources, are permanently implanted into the tissue. The radiation emitted during this procedure is usually low (LDR = Low- Dose Rate).

In the case of clearly localised tumours, this prevents recurrences and reduces the side effects, as only the cancer is irradiated. The other procedure, temporary HDR brachytherapy, allows the application of high-dose radiation (HDR = High-Dose Rate). In most cases, this method is used in addition to the classical radiation in order to enhance the effect.

Furthermore, there is also the intensity-modulated radiotherapy (IMRT). It enables a targeted radiation therapy, but the planning of this procedure is very complex. For patients in an advanced stage, who already have bone metastases, radionuclides can be used. These are administered by infusion and accumulate in the bone. In this way, tumor-associated pain can be relieved and the patient’s quality of life can be improved.

How is the preparation for the radiation treatment?

An individual treatment plan is created for each patient. The aim of this treatment plan is the optimal irradiation of the tumor, whereas the surrounding tissue and neighboring organs should be spared as much as possible. The preparation for this includes the analysis of previous examinations and the preparation of a new CT.

The CT produces a large number of cross-sections to determine the exact location of the tumour. In addition, the exact anatomy of the patient is recorded. With the help of this CT, medical physicists and radiotherapy specialists create a tailor-made plan.

Skin markings are then applied to determine the exact location. These markings should not be washed off, as they are needed in the further course of the treatment. Once the plan has been drawn up, the first radiation treatment is carried out.

The irradiation fields are checked to make sure that they correspond to the calculated data. Then the daily irradiation follows. In brachytherapy, on the other hand, an implantation plan is created using additional software. This determines the exact location of the radiation sources.