Primary treatment modalities applied for low and intermediaterisk prostate cancer produce similar treatment outcome. The excellent prognosis of some of the low-risk patients despite lack of treatment produces concern about overtreatment in these patients, whereas a controversy still exists about the optimal treatment strategy in intermediate-risk disease. Definitive radiotherapy is one of the primary treatment modalities in localized prostate cancer. It can be applied either as external radiotherapy (ERT) or brachytherapy (BRT). Biochemical disease control is very high with either modality. ERT or BRT can be applied as monotherapy in low-risk disease, whereas the combinations of ERT ± BRT ± hormonotherapy is considered in intermediate-risk disease. Although the role of hormonotherapy with high-dose RT is controversial in intermediate-risk patients, generally short-term hormonotherapy neoadjuvant and concurrent with ERT is applied.

Ideal patients for BRT as monotherapy are the patients with lowrisk disease. The role of brachytherapy as monotherapy in intermediate- risk prostate cancer has not been clearly defined. The combination of ERT and BRT is prefered in these patients despite lack of sufficient evidence. Neoadjuvant or adjuvant hormonotherapy added to BRT has no benefit.

Due to the lower α/β ratio of the prostate cancer a therapeutic advantage could be gained with hypofractionated RT and stereotactic body radiotherapy; however they are not considered as the standard and the validity of the data has to be justified after longer follow-up. Proton therapy is a promising but still an experimental approach.

The patient's choice, age, general health status, comorbidity, life expectancy, risk/benefit ratio and the facilities of the treatment center should be considered for the choice of treatment. In the future new imaging modalities and molecular markers will help to identify a subgroup of patients with agressive disease. With individualized treatment it will be possible to improve outcome, prevent unnecessary treatment and treatment-related morbidity and to increase cost effectiveness.

Keywords: Radiotherapy, brachytherapy, low-risk prostate cancer, intermediate-risk prostate cancer