The purpose of this study is to determine whether adjuvant radiotherapy following radical prostatectomy in prostate cancer patients with positive margins or capsular penetration improves biochemical, overall and/or cancer specific survival and whether adjuvant radiotherapy is reasonably well tolerated when compared to watchful waiting.

In this study the investigators will evaluate adjuvant radiation therapy vs. watchful waiting in prostate cancer patients with positive margins or capsular penetration after radical prostatectomy. This is a randomized, open label, multicentre, collaborative study of FinnProstate Group and Finnish Radiation Oncology group.

Inclusion Criteria:

Patients with pT3aN0M0 or pT2N0M0 prostate cancer with a positive margin, gleason score 2-10, preoperative PSA < 20 ug/l, postoperative PSA <0.5 ug/l after surgery (within 8 weeks), the WHO performance status 0-2, life expectancy at least 3 months, informed consent obtained.

Exclusion Criteria:

Other simultaneous cancer therapy including systemic endocrine therapy; more than 12 weeks has elapsed since surgery for prostate cancer; metastatic disease (N+ or M1); cancer invasion to the seminal vesicles; any other previous malignancy within the last 5 years except basalioma or squamous cell carcinoma of the skin; any contraindication to irradiation (severe locoregional infection, prior radiation therapy to the prostate/bladder); any physical or mental condition, which in the opinion of the investigator, may interfere with patient's ability to comply with scheduled visits.