Patients with clinically localised prostate cancer have a favourable long-term overall and cancer-specific rate of survival regardless of treatment choice. 

There are currently no completed prospective, randomised trials that evaluate differences in survival outcomes between radical prostatectomy and external-beam radiation therapy. Consequently, predicted functional outcomes have become essential components of treatment decision making. 

Although studies with short-term follow-up (one to three years) and intermediate-term follow-up (four to five years) have identified incremental differences in functional outcomes between patients undergoing prostatectomy and those undergoing radiotherapy, longer-term outcomes remain largely unknown. 

Since the median life expectancy after treatment for prostate cancer is 13.8 years, a careful evaluation of long-term functional outcomes is critical to an understanding of the comprehensive experience of men living with a diagnosis of prostate cancer.

The goal of this US-based study¹ was to compare urinary, bowel and sexual function and the extent to which men were bothered by declines in function 15 years after prostatectomy or radiotherapy for clinically localised prostate cancer. 

The authors used data from the Prostate Cancer Outcomes Study (PCOS), a population-based cohort of men in whom prostate cancer had been diagnosed in the mid-1990s and who had been followed prospectively for 15 years. 

Patients undergoing prostatectomy were more likely to have urinary incontinence than were those undergoing radiotherapy at two years (odds ratio, 6.22; 95% confidence interval [CI], 1.92-20.29) and five years (odds ratio, 5.10; 95% CI, 2.29-11.36). 

However, no significant between-group difference in the odds of urinary incontinence was noted at 15 years. Similarly, although patients undergoing prostatectomy were more likely to have erectile dysfunction at two years (odds ratio, 3.46; 95% CI, 1.93-6.17) and five years (odds ratio, 1.96; 95% CI, 1.05-3.63), no significant between-group difference was noted at 15 years. 

Patients undergoing prostatectomy were less likely to have bowel urgency at two years (odds ratio, 0.39; 95% CI, 0.22-0.68) and five years (odds ratio, 0.47; 95% CI, 0.2-0.84), again with no significant between-group difference in the odds of bowel urgency at 15 years.

Assessment of five-year outcomes in the current study revealed numerous differences between the two study groups. 

Specifically, men who underwent prostatectomy were five times as likely as those who underwent radiotherapy to have urinary incontinence and twice as likely to have erectile dysfunction. Furthermore, at five years, men in the prostatectomy group were more likely to be bothered by urinary incontinence than were those in the radiotherapy group (odds ratio, 7.66; 95% CI, 2.90-19.89). 

Despite these differences, there were no significant differences in the adjusted odds of urinary incontinence or erectile dysfunction between the two study groups at 15 years. 

Nonetheless, men treated for localised prostate cancer commonly had declines in all functional domains during 15 years of follow-up.

Reference

1. Resnick MJ, Koyama T, Fan KH et al, N Engl J Med 2013; 368: 436-445