Investigators compare in a randomized clinical trial the results and side effects of high-dose- and low-dose-rate brachytherapy as monotherapy in the treatment of early, organ confined prostate cancer patients.

Permanent implant prostate brachytherapy (LDRPBT) is a well established and proved method in the treatment of patients with low or selected intermediate risk, organ confined prostate cancer.

There are number of studies with high-dose rate brachytherapy (HDRPBT) as monotherapy with several fractionation schedule treating the same group of patients. One phase II trial showed its effectiveness given in one fraction of 19 Gy.

In the trial investigators randomly select patients to treat with either LDR prostate brachytherapy (145Gy) or HDR prostate brachytherapy (1x19Gy) as monotherapy.

Patients are stratified into two pretreatment group: 1. low risk, 2. selected intermediate risk group.

Brachytherapy is given in spinal anaesthesia, using transrectal ultrasound based real time treatment planning. Dose constraints are defined for both methods.

Inclusion Criteria:

• Eastern Cooperative Oncology Group (ECOG) status <=1
• 40-75 years old
• expected life expectancy>10 years
• low risk prostate cancer (Prostate specific antigen (PSA)<=10ng/ml, gleason score <7, T status<=2a), less than 50 % positive biopsy cores
• selected intermediate prostate cancer (PSA)=10-<15ng/ml or gleason score =3+4(but not 4+3), or T2b-c, less than 50 % positive biopsy cores)
• International prostate symptom score (IPSS) <=15
• Prostate volume<=50cm3
• no pubic interference
• no prior prostate operation, except biopsy
• no prior radiation to pelvis
• patient signed the informed consent

Exclusion Criteria:

• <40 years or >75 years old
• PSA>15 ng/ml gleason score 4+3 , score 8-10
• ECOG>=2
• T3-4
• percent core positivity >50 %
• TUR operation within six months prior to the brachytherapy prostate volume<10 cm3 or >50 cm3 IPSS >15