Disease-specific health-related outcomes regarding quality of life are essential components of decision making for any man with prostate cancer.21-23
However, the literature largely reports only outcomes that are short-term (1 to 3 years) or intermediate-term (4 to 5 years), which may not reflect the long-term experience of men undergoing treatment for prostate cancer. We have previously reported short- and intermediate-term functional outcomes after prostatectomy or radiotherapy for localized prostate cancer in the PCOS.7-9
This report of 15-year outcomes represents a mature portrait of patient-reported, disease-specific health-related quality-of-life outcomes in a population-based longitudinal cohort.
Assessment of 5-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 5 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 to 19.89). Despite these differences, we observed no significant differences in the adjusted odds of urinary incontinence or erectile dysfunction between the two study groups at 15 years.
Our study has a number of important findings. At 15 years, the prevalence of erectile dysfunction was nearly universal, affecting 87.0% of men in the prostatectomy group and 93.9% of those in the radiotherapy group. Nonetheless, only 43.5% of men in the prostatectomy group and 37.7% of those in the radiotherapy group reported being bothered with respect to sexual symptoms. The possible reasons for the second finding include declining sexual interest with age, acceptance of sexual dysfunction over time, or both. Despite some evidence of stabilization or improvement of urinary and sexual symptoms from 2 to 5 years, long-term follow-up reveals consistent functional declines after 5 years. It remains unknown whether this continued decline is due to prostate cancer and its treatment, the normal aging process, or a combination of factors.
Multiple reports have detailed significant functional declines after either prostatectomy or radiotherapy for prostate cancer. Sanda et al.24
found that 58% of men who had undergone prostatectomy and 60% of those who had undergone radiotherapy had poor-quality erections 2 years after treatment. Furthermore, 14% of men who had undergone prostatectomy and 7% of those who had undergone radiotherapy had urinary incontinence.24
Various investigators have reported similar short- and medium-term declines in diverse populations within different health care systems.25-29
The Scandinavian Prostate Cancer Group 4 (SPCG-4) trial,30
in which men were randomly assigned to undergo prostatectomy or monitoring only (“watchful waiting”), recently reported quality-of-life outcomes at a median follow-up of 12.2 years. Similar to long-term data from the PCOS, erectile dysfunction (84%) and sexual distress (48%) were common among men who had undergone prostatectomy. They were also more likely to have daily urinary incontinence than were those assigned to watchful waiting. Unlike the results from the PCOS, which revealed some recovery in erectile function up to 5 years, longitudinal outcomes from the SPCG-4 trial did not show the same trends with respect to the risk of erectile dysfunction, with rates of 80% at 2 to 3 years, 78% at 4 to 5 years, and 83% at 6 to 8 years.30
Certainly, differences in time-dependent rates of sexual dysfunction may be related to differences in clinical and disease characteristics between the two study populations.
Regardless of treatment, patients in the PCOS had significant declines in sexual and urinary function over the duration of the study. The causes of these declines probably include both advancing age and additional cancer treatments. Indeed, patients without prostate cancer have age-related urinary and sexual dysfunction. Litwin,31
who administered the University of California Los Angeles Prostate Cancer Index (UCLA-PCI) to a population of 598 men (median age, 73 years) without prostate cancer, found that 50% were unable to achieve an erection sufficient for intercourse and 32% were unable to achieve an erection sufficient for any sexual activity. Urinary incontinence was reported in 31% of men, with at least weekly urinary incontinence reported in 18%. In their report on 5-year functional outcomes in men with localized prostate cancer and matched controls, Hoffman et al.32
found a decline in sexual function among controls, although the magnitude of this change was far less than that of men treated for prostate cancer. Furthermore, although urinary and bowel function remained stable in the control group, men with prostate cancer had declines in both urinary and bowel function. A recent cross-sectional report from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial reported similar findings at 10 years.33
Despite these data, the longitudinal evolution of these changes from 5 years to 15 years in men without prostate cancer remains unknown.
Several limitations of this study must be considered when interpreting these results. At the time of the long-term survey, there were between-group differences in rates of questionnaire non-response that were largely the result of differential death rates according to treatment. Although data imputation minimizes bias associated with differential nonresponse, nonrandom loss to follow-up may introduce systematic bias. Furthermore, both death and loss to follow-up result in a sample-size reduction that may have limited our ability to detect small differences between the two study groups. This may explain the observed absolute differences in functional outcomes in the absence of significant relative differences. Although an analysis of propensity scoring addresses known confounding, it cannot control for confounding because of unmeasured characteristics. Like all other PCOS analyses, measures of baseline function were ascertained 6 months after diagnosis. Retrospective recall of baseline function may differ from prospective assessment, though data suggest that recall is likely to have a small effect on estimates of change over time.10
In addition, although this analysis evaluated urinary incontinence, only the 15-year survey included irritative voiding dysfunction, thereby limiting the longitudinal evaluation of this domain. Finally, although we evaluated the comparative harms of prostatectomy and radiotherapy, the precise contribution of prostate-cancer treatment to age-dependent changes in urinary, sexual, and bowel function remains unknown, given the absence of an untreated, age-matched control cohort.
In conclusion, men undergoing prostatectomy or radiotherapy for localized prostate cancer had declines in all functional outcomes throughout early, intermediate, and long-term follow-up. Whereas short- and intermediate-term data reveal differences in functional profiles among men undergoing prostatectomy and radiotherapy, at 15 years we observed no significant relative between-group differences. Considering the often long duration of survival after treatment for prostate cancer, these data may be used to counsel men considering treatment for localized disease.