Background:Although the prognosis of localised prostate cancer is good, the negative effects of prostate cancer treatment often impair patient quality of life. A growing number of men experience these negative effects over a longer time because of the increased incidence of and prolonged survival in prostate cancer, and the ageing of the population. Only a few studies have investigated the adverse effects of different prostate cancer treatments using large population-based samples.Methods:We conducted a nationwide survey (n=1239) to collect detailed information regarding the negative effects (i.e., the occurrence, perceived level and perceived bother since the beginning of the treatment) of prostate cancer treatments: radical prostatectomy, external beam radiotherapy, brachytherapy, hormone therapy and surveillance. Furthermore, we measured patient satisfaction with the outcome of the treatment and their psychological well-being (i.e., psychological symptoms and satisfaction with life) 5 years after diagnosis. The negative effects between the treatments were compared, and the determinants of satisfaction and psychological well-being were investigated.Results:The negative effects of all types of active prostate cancer treatments were common and persistent (33–48% reported symptoms at 5 years) and showed the known differences between the treatments. Prostatectomy and the radiotherapies caused urinary leakage; radiotherapy also caused symptoms of urinary irritation; and external radiation also caused bowel dysfunction. Most symptoms were considered highly bothersome. Most respondents (81−93%) reported that their treatment negatively affected their sex lives; 70–92% reported sexual dysfunction; and 20–58% reported that their sex lives with their spouses had ended. Urinary symptoms were especially associated with poorer psychological outcomes. The perception of symptom level and bother had a greater effect on patient satisfaction and well-being than the symptoms per se.Conclusion:Multiple and persistent negative effects follow active prostate cancer treatment, and these effects predict long-term patient satisfaction and psychological well-being. The harms and benefits associated with prostate cancer treatments should be considered when selecting whether and how to actively treat prostate cancer.