Although short-to medium-term functional outcomes favoured radiotherapy over surgery in terms of sexual and urinary function in localised prostate cancer, by 15 years follow-up there were no differences in functional outcomes between the two treatment groups, in the Prostate Cancer Outcomes Study.

A cohort of 1,655 men, diagnosed with clinically localised prostate cancer between 55 and 74 years of age, in the mid 1990s, were followed prospectively in the Prostate Cancer Outcomes Study (PCOS). Of these, 1,164 men had undergone radical surgery and 491 radical radiotherapy. Functional status was assessed at baseline, two, five and 15 years after diagnosis.

The three main areas of functional outcome assessed were urinary incontinence, sexual function and bowel function.

Men in the prostatectomy group were more likely to be incontinent at two and five years than those in the radiotherapy group; odds ratio (OR) 6.2 (95% CI:1.92-20.29) and OR 5.10 (95% CI:2.29-11.36) respectively. At 15 years, although 18% of prostatectomy patients had some degree of incontinence compared with 9% of radiotherapy patients, this did not reach statistical significance; OR 2.34 (95% CI:0.88–6.23). Patients in the prostatectomy group were, however, more likely to wear incontinence pads at all study points.

There were very similar findings with regard to sexual function, with prostatectomy patients more likely to have erectile dysfunction (ED) than radiotherapy patients at two and five years; OR 3.46 (95% CI:1.93-6.17) and OR 1.96 (95% CI: 1.05-3.63) respectively. By 15 years, 87% of patients in the prostatectomy group and 94% in the radiotherapy group suffered from ED, with no statistically significant difference between the groups OR 0.38 (95% CI:0.12-1.22)

Bowel urgency was seen more often in radiotherapy patients at two and five years; OR 0.39 (95% CI:0.22-0.68) and OR 0.47 (95% CI:0.26-0.84) respectively. However, there was no significant difference between the two groups at 15 years, 21.9% and 35.8% respectively, OR 0.98 (95% CI:0.45–2.14).

Short- to medium-term functional outcomes would appear to favour radical radiotherapy in terms of both sexual and urinary function. Men undergoing prostatectomy were five times more likely to suffer from incontinence and twice as likely to have ED when assessed at five years.

However, it is interesting to see this difference decrease to non-significance by 15 years. ED was almost universal by this time. These figures correlate well with findings of epidemiological studies which have shown extremely high rates of ED in men of this age group, who could be seen almost as age-matched controls for this study population.

Patients often have to choose between these two forms of treatment, and therefore long-term follow-up data on side effects of treatment is vital to help them with this difficult decision.

Dr Jonathan Rees

• Resnick MJ, Koyama T, Fan K-H et al. Long-term functional outcomes after treatment for localized prostate cancer. N Engl J Med 2013;368(5):436-45